TAO SHANSHAN (SG)
TAN KE TIAN (SG)
SHANSHAN TAO: "Confining H3PO4 network in covalent organic frameworks enables proton super flow", NATURE COMMUNICATIONS, NATURE PUBLISHING GROUP, UK, vol. 11, no. 1, UK, XP093155214, ISSN: 2041-1723, DOI: 10.1038/s41467-020-15918-1
| Claims 1. A proton-conducting membrane for a proton exchange membrane fuel cell comprising: a non-proton conducting covalent organic framework comprising a plurality of imine linkages and a plurality of pores each having an interior wall; and a plurality of phosphoric acid molecules disposed within the plurality of pores. 2. The proton-conducting membrane according to Claim 1, wherein a portion of the plurality of imine linkages comprise a nitrogen atom having a lone pair extending inwards from an interior wall of the plurality of pores. 3. The proton-conducting membrane according to Claim 1 or 2, wherein the non-proton conducting covalent organic framework has a conductivity of less than 10-11 S cm–1. 4. The proton-conducting membrane according to any one of the preceding claims, wherein the proton-conducting membrane is suitable for use at a temperature of from 100 to 180°C, optionally a temperature of from 120 to 180°C, more optionally a temperature of from 140 to 180°C, such as about 160°C. 5. The proton-conducting membrane according to any one of the preceding claims, wherein the proton-conducting membrane comprises less than 0.05 wt. % water. 6. The proton-conducting membrane according to any one of the preceding claims, wherein the weight ratio of covalent organic framework to phosphoric acid is from 10:1 to 1:3. 7. The proton-conducting membrane according to any one of the preceding claims, wherein the covalent organic framework has a geometry selected from the group consisting of hexagonal, tetragonal, trigonal and kagome. 8. The proton-conducting membrane according to any one of the preceding claims, wherein the interior walls of the plurality of pores comprise one or more functional groups selected from the group consisting of -OH, -OR, -R, -X and -(OCH2)zOCH3, wherein R represents a C1-3 alkyl group; X represents F, Cl or Br; and z represents an integer of from 1 to 10. 9. The proton-conducting membrane according to any one of the preceding claims, wherein the interior walls of the plurality of pores comprise one or more functional groups selected from the group consisting of -OH, -OMe, -Me, -F, -Br and -(OCH2)zOCH3. 10. The proton-conducting membrane according to any one of the preceding claims, wherein the proton-conducting membrane has a conductivity of at least 10-2 S cm-1, such as at least 10-1 S cm-1. 11. The proton-conducting membrane according to any one of the preceding claims, wherein the covalent organic framework comprises a substructure selected from the following a) to k): ; , where the dashed lines represent points of attachment to the rest of the covalent organic framework, and wherein in each of a) to k), R, R1, R2, R3, and R4 are each independently selected from the group consisting of H, -OH, -OR, -R, -X and -(OCH2)zOCH3, wherein R represents a C1-3 alkyl group; X represents F, Cl or Br; and z represents an integer of from 1 to 10. 12. The proton-conducting membrane according to Claim 11, wherein R, R1, R2, R3, and R4 are each independently selected from the group consisting of H, -OH, -OMe, -Me, -F, -Br and -(OCH2)zOCH3. 13. The proton-conducting membrane according to Claim 11 or 12, wherein option a) applies and either: (i) R1 and R2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1 represents H and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (iii) R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3 and R2 represents H. 14. The proton-conducting membrane according to Claim 11 or 12, wherein option b) applies and either: (i) R1-R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1-R3 represent H, and R4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iii) R1, R2 and R4 represent H, and R3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iv) R1, R3 and R4 represent H, and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (v) R2-R4 represent H; and R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vi) R3-R4 represent H, and R1-R2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vii) R1 and R2 represent H, and R3 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (viii) R1 and R3 represent H, and R2 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (ix) R1 and R4 represent H, and R2 and R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 15. The proton-conducting membrane according to Claim 11 or 12, wherein option c) applies and R represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 16. The proton-conducting membrane according to Claim 11 or 12, wherein option d) applies and either: (i) R1-R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1-R2 represent H, and R3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iii) R2-R3 represent H, and R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (iv) R1 and R3 represent H, and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; 17. The proton-conducting membrane according to Claim 11 or 12, wherein option e) applies and either: (i) R1-R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1-R2 represent H, and R3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iii) R2-R3 represent H, and R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (iv) R1 and R3 represent H, and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 18. The proton-conducting membrane according to Claim 11 or 12, wherein option f) applies and either: (i) R1-R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R2 and R3 represent H, and R1 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (iii) R1 and R4 represent H, and R2 and R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 19. The proton-conducting membrane according to Claim 11 or 12, wherein option g) applies and either: (i) R1-R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1-R3 represent H, and R4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iii) R1, R2 and R4 represent H, and R3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iv) R1, R3 and R4 represent H, and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (v) R2-R4 represent H; and R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vi) R3-R4 represent H, and R1-R2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vii) R1 and R2 represent H, and R3 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (viii) R1 and R3 represent H, and R2 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (ix) R1 and R4 represent H, and R2 and R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 20. The proton-conducting membrane according to Claim 11 or 12, wherein option h) applies and either: (i) R1-R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1-R3 represent H, and R4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iii) R1, R2 and R4 represent H, and R3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iv) R1, R3 and R4 represent H, and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (v) R2-R4 represent H; and R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vi) R3-R4 represent H, and R1-R2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vii) R1 and R2 represent H, and R3 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (viii) R1 and R3 represent H, and R2 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (ix) R1 and R4 represent H, and R2 and R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 21. The proton-conducting membrane according to Claim 11 or 12, wherein option i) applies and either: (i) R1-R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1-R3 represent H, and R4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iii) R1, R2 and R4 represent H, and R3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iv) R1, R3 and R4 represent H, and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (v) R2-R4 represent H; and R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vi) R3-R4 represent H, and R1-R2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vii) R1 and R2 represent H, and R3 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (viii) R1 and R3 represent H, and R2 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (ix) R1 and R4 represent H, and R2 and R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 22. The proton-conducting membrane according to Claim 11 or 12, wherein option j) applies and either: (i) R1-R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R1-R3 represent H, and R4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iii) R1, R2 and R4 represent H, and R3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (iv) R1, R3 and R4 represent H, and R2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (v) R2-R4 represent H, and R1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vi) R3-R4 represent H, and R1-R2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (vii) R1 and R2 represent H, and R3 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (viii) R1 and R3 represent H, and R2 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (ix) R1 and R4 represent H, and R2 and R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 23. The proton-conducting membrane according to Claim 11 or 12, wherein option k) applies and either: (i) R1-R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; (ii) R2 and R3 represent H, and R1 and R4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3; or (iii) R1 and R4 represent H, and R2 and R3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH2)zOCH3. 24. A covalent organic framework as defined in any one of Claims 11 to 23, provided that the covalent organic framework is not: where each of Ri to R4 represent H. 25. A proton exchange membrane fuel cell comprising a proton-conducting membrane as defined in any one of Claims 1 to 23. |
Therefore, to overcome least one of the aforementioned problems, there is a need for new COFs for use as solid proton-conducting membranes.
Summary of Invention
Aspects and embodiments of the invention are provided in the following numbered clauses.
1. A proton-conducting membrane for a proton exchange membrane fuel cell comprising: a non-proton conducting covalent organic framework comprising a plurality of imine linkages and a plurality of pores each having an interior wall; and a plurality of phosphoric acid molecules disposed within the plurality of pores.
2. The proton-conducting membrane according to Clause 1 , wherein a portion of the plurality of imine linkages comprise a nitrogen atom having a lone pair extending inwards from an interior wall of the plurality of pores.
3. The proton-conducting membrane according to Clause 1 or 2, wherein the non-proton conducting covalent organic framework has a conductivity of less than 10 -11 S cm -1 .
4. The proton-conducting membrane according to any one of the preceding clauses, wherein the proton-conducting membrane is suitable for use at a temperature of from 100 to 180°C, optionally a temperature of from 120 to 180°C, more optionally a temperature of from 140 to 180°C, such as about 160°C.
5. The proton-conducting membrane according to any one of the preceding clauses, wherein the proton-conducting membrane comprises less than 0.05 wt. % water.
6. The proton-conducting membrane according to any one of the preceding clauses, wherein the weight ratio of covalent organic framework to phosphoric acid is from 10:1 to 1 :3.
7. The proton-conducting membrane according to any one of the preceding clauses, wherein the covalent organic framework has a geometry selected from the group consisting of hexagonal, tetragonal, trigonal and kagome. 8. The proton-conducting membrane according to any one of the preceding clauses, wherein the interior walls of the plurality of pores comprise one or more functional groups selected from the group consisting of -OH, -OR, -R, -X and -(OCH 2 ) z OCH 3 , wherein R represents a C 1-3 alkyl group; X represents F, Cl or Br; and z represents an integer of from 1 to 10. 9. The proton-conducting membrane according to any one of the preceding clauses, wherein the interior walls of the plurality of pores comprise one or more functional groups selected from the group consisting of -OH, -OMe, -Me, -F, -Br and -(OCH 2 ) z OCH 3 10. The proton-conducting membrane according to any one of the preceding clauses, wherein the proton-conducting membrane has a conductivity of at least 10 -2 S cm -1 , such as at least 10 -1 S cm -1 . 11. The proton-conducting membrane according to any one of the preceding clauses, wherein the covalent organic framework comprises a substructure selected from the following a) to k): a)
, where the dashed lines represent points of attachment to the rest of the covalent organic framework, and wherein in each of a) to k), R, R 1 , R 2 , R 3 , and R 4 are each independently selected from the group consisting of H, -OH, -OR, -R, -X and -(OCH 2 ) z OCH 3 , wherein R represents a C 1-3 alkyl group; X represents F, Cl or Br; and z represents an integer of from 1 to 10. 12. The proton-conducting membrane according to Clause 11, wherein R, R 1 , R 2 , R 3 , and R 4 are each independently selected from the group consisting of H, -OH, -OMe, -Me, -F, -Br and -(OCH 2 ) z OCH 3 . 13. The proton-conducting membrane according to Clause 11 or 12, wherein option a) applies and either: (i) R 1 and R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 represents H and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iii) R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 and R 2 represents H. 14. The proton-conducting membrane according to Clause 11 or 12, wherein option b) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 15. The proton-conducting membrane according to Clause 11 or 12, wherein option c) applies and R represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 16. The proton-conducting membrane according to Clause 11 or 12, wherein option d) applies and either: (i) R 1 -R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 2 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 2 -R 3 represent H, and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iv) R 1 and R 3 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; 17. The proton-conducting membrane according to Clause 11 or 12, wherein option e) applies and either: (i) R 1 -R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 2 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 2 -R 3 represent H, and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iv) R 1 and R 3 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 18. The proton-conducting membrane according to Clause 11 or 12, wherein option f) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 2 and R 3 represent H, and R 1 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iii) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 19. The proton-conducting membrane according to Clause 11 or 12, wherein option g) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 20. The proton-conducting membrane according to Clause 11 or 12, wherein option h) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 21. The proton-conducting membrane according to Clause 11 or 12, wherein option i) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 22. The proton-conducting membrane according to Clause 11 or 12, wherein option j) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 23. The proton-conducting membrane according to Clause 11 or 12, wherein option k) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 2 and R 3 represent H, and R 1 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iii) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . 24. A covalent organic framework as defined in any one of Clauses 11 to 23, provided that the covalent organic framework is not:
25. A proton exchange membrane fuel cell comprising a proton-conducting membrane as defined in any one of Clauses 1 to 23.
Drawings
FIG. 1 depicts PXRD patterns of COFs for solid-state proton-conducting membranes, (a) TPB- TRBPDA-COFs (TPB-TMBPDA-COF). (b) TPB-DRTP-COFs (TPB-DMeTP-COF). (c) TTRA- TTRB-COFs (TTA-TTB-COF). (d) TTA-TFRB-COFs (TTA-TFB-COF). (e) ACOFs (ACOF-1). (f) Py-TRQPDA-COFs (Py-TMQPDA-COFs). (g) Py-2,2’-BPyPhR-COFs (Py-2,2’-BPyPh- COF). (h) Py-DRTP-COFs (Py-DMTP-COF). (i) [9,9'-bicarbazole]-3,3',6,6'-tetracarbaldehyde (TFBCz)-RPDA-COFs (TFBCz-PDA-COFs). (j) 4, 4', 4", 4"', 4"", 4 -(triphenylene-2,3,6,7,10,11- hexayl)hexabenzaldehyde (HFPTP)-RPDA-COFs (HFPTP-PDA-COF). (k) HFPTP-R- benzidine (RBPDA)-COFs (HFPTP-BPDA-COF). FIG. 2 depicts nitrogen adsorption isotherms of COFs for solid-state proton-conducting membranes. (a) TPB-TRBPDA-COFs (TPB-TMBPDA-COF). (b) TPB-DRTP-COFs (TPB- DMeTP-COF). (c) TTRA-TTRB-COFs (TTA-TTB-COF). (d) TTA-TFRB-COFs (TTA-TFB- COF). (e) ACOFs (ACOF-1). (f) Py-TRQPDA-COFs (Py-TMQPDA-COFs). (g) Py-2,2’- BPyPhR-COFs (Py-2,2’-BPyPh-COF). (h) Py-DRTP-COFs (Py-DMTP-COF). (i) TFBCz- RPDA-COFs (TFBCz-PDA-COFs). (j) HFPTP-RPDA-COFs (HFPTP-PDA-COF). (k) HFPTP- RBPDA-COFs (HFPTP-BPDA-COF). FIG.3 depicts characterization. PXRD patterns of (a) TPB-DMeTP-COF and (b) phosphoric acid-TPB-DMeTP-COF hybrids. (c) Nitrogen adsorption isotherms of samples measured at 77 K, the filled circles are adsorption data points and open circles are desorption data points. Phosphoric acid-TPB-DMeTP-COF hydrids: 43.92 wt% (i), 87.84 wt% (ii), 146.4 wt% (iii), 175.68 wt% (iv), 204.96 wt% (v), 234.24 wt% (vi), 292.8 wt% (vii) and TPB-DMeTP-COF (viii). (d) Pore size distribution and pore volume profile of TPB-DMeTP-COF. (e) Fourier transform infrared (FTIR) spectra of phosphoric acid-TPB-DMeTP-COF hybrids: 3.92 wt% (i), 87.84 wt% (ii), 146.4 wt% (iii), 175.68 wt% (iv), 204.96 wt% (v), 234.24 wt% (vi), 292.8 wt% (vii) and TPB- DMeTP-COF (viii). FIG.4 depicts characterization. (a) PXRD patterns of TPB-DMTP-COF (i), phosphoric acid- TPB-DMTP-COF hybrids (ii), and half filled pores of phosphoric acid-TPB-DMTP-COF hybrids (iii). (b) Nitrogen adsorption isotherms of samples measured at 77 K, the filled circles are adsorption data points and open circles are desorption data points. TPB-DMTP-COF (i) and phosphoric acid-TPB-DMTP-COF hybrids (ii) and half filled pores of phosphoric acid-TPB- DMTP-COF hybrids (iii). (c, d) Pore size distribution and pore volume profile of TPB-DMTP- COF. (e) FTIR spectra of phosphoric acid-TPB-DMTP-COF hybrids (ii) and half filled pores of phosphoric acid-TPB-DMTP-COF hybrids (iii) and TPB-DMTP-COF (i). FIG.5 depicts characterization. (a) PXRD patterns of TTA-TTB-COF (i), phosphoric acid-TTA- TTB-COF hybrids (ii), and half filled pores of phosphoric acid-TTA-TTB-COF hybrids (iii). (b) Nitrogen adsorption isotherms of samples measured at 77 K, the filled circles are adsorption data points and open circles are desorption data points. TTA-TTB-COF (i), phosphoric acid- TTA-TTB-COF hybrids (ii) and half filled pores of phosphoric acid-TTA-TTB-COF hybrids (iii). (c, d) Pore size distribution and pore volume profile of TTA-TTB-COF. (e) FTIR spectra of TTA-TTB-COF (i), phosphoric acid-TTA-TTB-COF hybrids (iii) and half filled pore of phosphoric acid-TTA-TTB-COF hybrids (ii). FIG.6 depicts characterization. (a) PXRD patterns of TTA-TFB-COF (i) and phosphoric acid- TTA-TFB-COF hybrids (ii). (b) Nitrogen adsorption isotherms of samples measured at 77 K, the filled circles are adsorption data points and open circles are desorption data points. TTA- TFB-COF (i) and phosphoric acid-TTA-TFB-COF hybrids (ii). (c, d) Pore size distribution and pore volume profile of TTA-TFB-COF. (e) FTIR spectra of phosphoric acid-TTA-TFB hybrids (ii) and TTA-TFB-COF (i). FIG.7 depicts characterization. PXRD patterns of (a) ACOF-1 and (b) phosphoric acid-ACOF- 1 hybrids. (c) Nitrogen adsorption isotherms of samples measured at 77 K, the filled circles are adsorption data points and open circles are desorption data points. Phosphoric acid- ACOF-1 hybrids: 11.25 wt% (i), 22.51 wt% (ii), 37.52 wt% (iii), 45.02 wt% (iv), 52.52 wt% (v), 60.02 wt% (vi), 75.00 wt% (vii) and ACOF-1 (viii). (d) Pore size distribution and pore volume profile of ACOF-1. (e) FTIR spectra of phosphoric acid-ACOF-1 hybrids: 11.25 wt% (i), 22.51 wt% (ii), 37.52 wt% (iii), 45.02 wt% (iv), 52.52 wt% (v), 60.02 wt% (vi), 75.00 wt% (vii) and ACOF-1 (viii). FIG.8 depicts characterization. (a) PXRD patterns of TPB-TMBPDA-COF (i) and phosphoric acid-TPB-TMBPDA-COF hybrids (ii). (b) Nitrogen adsorption isotherms of samples measured at 77 K, the filled circles are adsorption data points and open circles are desorption data points. Phosphoric acid-TPB-TMBPDA-COF hybrids (ii) and TPB-TMBPDA-COF (i). (c) FTIR spectra of phosphoric acid-TPB-TMBPDA-COF hybrids (ii) and TPB-TMBPDA-COF (i). FIG. 9 depicts stability. (a) PXRD patterns of as-synthesized TPB-TMBPDA-COF (pristine) and TPB-TMBPDA-COF after treatments in Fenton test (Fenton), H 3 PO 4 , boiling water (water (100 °C)), aqueous HCl (12 M), and NaOH (14 M) solutions for 7 days. (b) Nitrogen sorption isotherms of TPB-TMBPDA-COF measured at 77 K of as-synthesized (i) and after treatments in Fenton test (ii), H 3 PO 4 (iii), boiling water (iv) or aqueous HCl (12 M; v), and NaOH (14 M; vi) solutions for 7 days (filled dots, adsorption; open dots, desorption). FIG.10 depicts stability. (a-f) Pore size distribution and pore volume profiles of TPB-TMBPDA- COF measured at 77 K as synthesized (a) and after 7-day treatment in boiling water (b), NaOH (14 M) (c), Fenton (d), H 3 PO 4 (e), and HCl (12 M) (f). FIG. 11 depicts the PXRD pattern of TPB-DMTP-COF after treatment under different conditions.
FIG. 12 depicts energy-dispersive X-ray spectroscopy (EDS), (a) Field emission scanning electron microscopy (FESEM) image of phosphoric acid-TPB-TMBPDA-COF hybrids, (b-e) Elemental distributions of (b) carbon, (c) nitrogen, (d) oxygen, and (e) phosphorus.
FIG. 13 depicts EDS. (a) FESEM image of phosphoric acid-TPB-DMeTP-COF hybrids, (b-e) Elemental distributions of (b) carbon, (c) nitrogen, (d) oxygen, and (e) phosphorus.
FIG. 14 depicts EDS. (a) FESEM image of phosphoric acid-TPB-DMTP-COF hybrids, (b-e) Elemental distributions of (b) carbon, (c) nitrogen, (d) oxygen, and (e) phosphorus.
FIG. 15 depicts EDS. (a) FESEM image of phosphoric acid-TTA-TTB-COF hybrids, (b-e) Elemental distributions of (b) carbon, (c) nitrogen, (d) oxygen, and (e) phosphorus.
FIG. 16 depicts EDS. (a) FESEM image of phosphoric acid-TTA-TFB-COF hybrids, (b-e) Elemental distributions of (b) carbon, (c) nitrogen, (d) oxygen, and (e) phosphorus.
FIG. 17 depicts EDS. (a) FESEM image of phosphoric acid-ACOF-1 hybrids, (b-e) Elemental distributions of (b) carbon, (c) nitrogen, (d) oxygen, and (e) phosphorus.
FIG. 18 depicts hexagonal pore size and Ea. (a, b) The relationship between activation energy and hexagonal pore size.
FIG. 19 depicts impedance spectroscopy, (a-f) Nyquist plots of different ratios of full filled phosphoric acid-TPB-DMeTP-COF hybrids: 15% (43.9 wt%), 30% (87.8 wt%), 50% (146.4 wt%), 60% (175.7 wt%), 70% (204.9 wt%), and 80% (234.2 wt%) measured at different temperatures. The curves for 100, 110, 120, 130, 140, 150 and 160 °C are (i), (ii), (iii), (iv), (v), (vi) and (vii), respectively.
FIG. 20 depicts impedance spectroscopy of different ratios of phosphoric acid-Py-2,2’-BPyPh- COF hybrids, (a-f) Nyquist plots of different ratios of full filled phosphoric acid-Py-2,2’-BPyPh- COF hybrids: 15% (21.4 wt%), 30% (42.8 wt%), 50% (71.4 wt%), 60% (85.6 wt%), 70% (99.9 wt%), and 80% (114.2 wt%) measured at different temperatures. The curves for 100, 110, 120, 130,140, 150 and 160 °C are (i), (ii), (iii), (iv), (v), (vi) and (vii), respectively. FIG. 21 depicts impedance spectroscopy of different ratios of phosphoric acid-HFPTP-BPDA- COF hybrids, (a-f) Nyquist plots of different ratios of full filled phosphoric acid-HFPTP-BPDA- COF hybrids: 15% (13.2 wt%), 30% (26.4 wt%), 50% (43.9 wt%), 60% (52.7 wt%), 70% (61 .5 wt%), and 80% (70.3 wt%) measured at different temperatures. The curves for 100, 110, 120, 130,140, 150 and 160 °C are (i), (ii), (iii), (iv), (v), (vii) and (viii), respectively.
FIG. 22 depicts impedance spectroscopy of different ratios of phosphoric acid-ACOF-1 hybrids (a-f) Nyquist plots of different ratios of full filled phosphoric acid-ACOF-1 hybrids: 15% (11.3 wt%), 30% (22.5 wt%), 50% (37.5 wt%), 60% (45.0 wt%), 70% (52.5 wt%), and 80% (60.0 wt%) measured at different temperatures. The curves for 100, 110, 120, 130,140, 150 and 160 °C are (i), (ii), (iii), (iv), (v), (vi) and (vii), respectively.
FIG. 23 depicts conductivity of different ratios of full filled phosphoric acid in phosphoric acid- TPB-DMeTP-COF, phosphoric acid-Py-BPyPh-COF, phosphoric acid-ACOF-1 and phosphoric acid-HFPTP-BPDA-COF hybrids.
FIG. 24 depicts impedance spectroscopy of half of full loading in phosphoric acid-COF hybrids, (a-c) Nyquist plots of half of full filled phosphoric acid in phosphoric acid-TPB-DMTP-COF hybrids (a), phosphoric acid-TTA-TTB-COF (b), and phosphoric acid-Py-TMQPDA-COF (c) measured at different temperatures. The curves for 100, 110, 120, 130,140, 150 and 160 °C are (i), (ii), (iii), (iv), (v), (vi) and (vii), respectively, (d) Temperature dependence of proton conductivities of half of full filled phosphoric acid in phosphoric acid-TPB-DMTP-COF hybrids (i), phosphoric acid-TTA-TTB-COF (iii) and phosphoric acid-Py-TMQPDA-COF (ii). Black lines are curve-fitting results.
FIG. 25 depicts the proton conductivity of fully loaded phosphoric acid-COFs measured from 100-160 °C.
FIG. 26 depicts the proton conductivity of phosphoric acid-TPB-DMeTP-COF hybrid membranes with different loading amounts of phosphoric acid, (a-g) 15%, 30%, 50%, 60%, 70%, 80% and 100% of the fully loaded pore ((i), (ii), (iii), (iv), (v), (vi), (vii) lines are 100, 110, 120, 130, 140, 150 and 160 °, respectively, (h) Temperature profiles of proton conductivities of phosphoric acid-COFs hybrids. Dots are experimental data and lines are curve fitting.
FIG. 27 depicts the proton conductivity of phosphoric acid-COF hybrid membranes of different COF topologies under full loading of phosphoric acid, (a) Hexagon (PA-TPB-DMeTP-COF). (b) Kagome (PA-Py-TMQPDA-COF). (c) Tetragon (PA-Py-BPyPh-COF). (d) Trigon (PA- HFPTP-BPDA-COF). (i), (ii), (iii), (iv), (v), (vi) and (vii) lines are 100, 110, 120, 130, 140, 150 and 160 °C, respectively.
FIG. 28 depicts the proton conductivity of phosphoric acid-COF hybrid membranes with different loading amounts of phosphoric acid, (a-g) 15%, 30%, 50%, 60%, 70%, 80% and 100% of the fully loaded pore in PA-TPB-DMeTP-COF. (h-n) 15%, 30%, 50%, 60%, 70%, 80% and 100% of the fully loaded pore in PA-Py-BPyPh-COF. (o-u) 15%, 30%, 50%, 60%, 70%, 80% and 100% of the fully loaded pore in PA-HFPTP-BPDA-COF. (i), (ii), (iii), (iv), (v), (vi) and (vii) lines are 100, 110, 120, 130, 140, 150 and 160 °C, respectively.
FIG. 29 depicts solid 31 P and 1 H NMR of different ratios of phosphoric acid in phosphoric acid- TPB-DMeTP-COF and TPB-DMeTP-COF.
FIG. 30 depicts 1 H variable temperature relaxation measurements.
FIG. 31 depicts COFs for solid proton-conducting membranes.
FIG. 32 depicts (a) PXRD patterns of phosphoric acid-HFPTP-BPDA-COF hybrids, (b) Nitrogen adsorption isotherms of samples measured at 77 K; the filled circles are adsorption data points and open circles are desorption data points. Phosphoric acid-HFPTP-BPDA-COF hybrids: 13.17 wt% (i), 26.35 wt% (ii), 43.92 wt% (iii), 52.70 wt% (iv), 61.49 wt% (v), 70.27 wt% (vi) and 87.8 wt% (vii). (c) FTIR spectra of phosphoric acid-HFPTPBPDA-COF hybrids: 13.17 wt% (i), 26.35 wt% (ii), 43.92 wt% (iii), 52.70 wt% (iv), 61 .49 wt% (v), 70.27 wt% (vi) and 87.8 wt% (vii) and HFPTP-BPDA-COF (viii).
FIG. 33 depicts (a) PXRD patterns of phosphoric acid-Py-BPyPh-COF hybrids, (b) Nitrogen adsorption isotherms of samples measured at 77 K; the filled circles are adsorption data points and open circles are desorption data points. Phosphoric acid-Py-BPyPh-COF hybrids: 21.41 wt% (i), 42.82 wt% (ii), 71.37 wt% (iii), 85.64 wt% (iv), 99.92 wt% (v), 114.19 wt% (vi) and 142.74 wt% (vii). (c) FTIR spectra of phosphoric acid-Py-BPyPh-COF hybrids: 21.41 wt% (i), 42.82 wt% (ii), 71.37 wt% (iii), 85.64 wt% (iv), 99.92 wt% (v), 114.19 wt% (vi) and 142.74 wt% (vii) and Py-BPyPh-COF (viii).
Description It has been surprisingly found that proton-conducting membranes formed from COFs are chemically and thermally stable, and exhibit proton conductivity of up to 10' 1 S cm' 1 at 160 °C, which may be a level for industrial application.
Thus, in a first aspect of the invention, there is provided a proton-conducting membrane for a proton exchange membrane fuel cell comprising: a non-proton conducting covalent organic framework comprising a plurality of imine linkages and a plurality of pores each having an interior wall; and a plurality of phosphoric acid molecules disposed within the plurality of pores.
In embodiments herein, the word “comprising” may be interpreted as requiring the features mentioned, but not limiting the presence of other features. Alternatively, the word “comprising” may also relate to the situation where only the components/features listed are intended to be present (e.g. the word “comprising” may be replaced by the phrases “consists of” or “consists essentially of”). It is explicitly contemplated that both the broader and narrower interpretations can be applied to all aspects and embodiments of the present invention. In other words, the word “comprising” and synonyms thereof may be replaced by the phrase “consisting of” or the phrase “consists essentially of’ or synonyms thereof and vice versa.
The phrase, “consists essentially of” and its pseudonyms may be interpreted herein to refer to a material where minor impurities may be present. For example, the material may be greater than or equal to 90% pure, such as greater than 95% pure, such as greater than 97% pure, such as greater than 99% pure, such as greater than 99.9% pure, such as greater than 99.99% pure, such as greater than 99.999% pure, such as 100% pure.
As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a copolymer” includes mixtures of two or more such copolymers, reference to “an interface” includes two or more such interfaces, reference to “the catalyst” includes mixtures of two or more such catalysts, and the like.
Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. As used herein, a “proton-conducting membrane” is a membrane suitable for use as a proton- exchange membrane (PEM) in a PEM fuel cell. As used herein, a “covalent organic framework” (COF) refers to a porous two- or three- dimensional structure formed from organic building blocks. Covalent organic frameworks comprise pores, and the size and shape of the pores will depend on the organic blocks the COF is formed from. Thus, the pore size and shape may be tailored for a specific application, such as improving the amount of conductive material (e.g. phosphoric acid) that may be loaded into the pores. The pores of a covalent organic framework define an interior wall, which interior wall may have chemical functionality that serves to anchor molecules within the pores. For example, the interior wall of the pores may comprise hydrogen bond donor or hydrogen bond acceptor groups that can form hydrogen bonds with molecules located inside the pores. For example, a COF may comprise a plurality of imine linkages on the interior wall of a pore, and the imine nitrogen atoms may have a conformation that enables the nitrogen lone pair to act as a hydrogen bond donor into the pore. As such, the nitrogen atoms having a lone pair may extend inwards from the interior wall of the plurality of pores. This may allow the proton-conducting membranes of the invention to have a higher loading of conductive material within the pores, leading to improved and advantageously high conductivity as compared to other membranes. In some embodiments of the invention that may be mentioned herein, the interior walls of the plurality of pores may comprise one or more functional groups selected from the group consisting of -OH, -OR, -R, -X and -(OCH 2 ) z OCH 3 , wherein R may represent a C 1-3 alkyl group; X may represent F, Cl or Br; and z may represent an integer of from 1 to 10. In some embodiments of the invention that may be mentioned herein, the interior walls of the plurality of pores may comprise one or more functional groups selected from the group consisting of -OH, -OMe, -Me, -F, -Br and -(OCH 2 ) z OCH 3 . Typically, the proton conducting membranes of the invention are suitable for use in PEM fuel cells under anhydrous conditions. The proton conducting membranes of the invention may be advantageously more stable under anhydrous conditions and high temperatures (e.g. from 100 to 180°C, from 120 to 180°C, from 140 to 180°C, such as about 160°C) than existing proton conducting membranes. In some embodiments of the invention that may be mentioned herein, the proton-conducting membrane may be suitable for use at a temperature of from 100 to 180°C. For example, the proton-conducting membrane may be suitable for use at a temperature of from 100 to 180°C, such as from 100 to 160°C, such as from 100 to 140°C, such as from 100 to 120°C, such as from 120 to 180°C, such as from 120 to 160°C, such as from 120 to 140°C, such as from 140 to 180°C, such as from 140 to 160°C, such as from 160 to 180°C, such as about 160°C. Without being bound by theory, it is believed that existing proton conducting membranes have less stable framework materials. While PEM fuel cells may produce water (e.g. the cathodic reaction in a hydrogen fuel cell), the proton conducting membranes of the invention are suitable for use under conditions in which any such water produced will be rapidly expelled from the cell, and therefore the proton conducting membranes of the invention may typically operate under anhydrous conditions. In some embodiments of the invention that may be mentioned herein, the proton-conducting membrane may comprise less than 0.05 wt. % water. Without being bound by theory, if all other factors are equal then a higher amount of phosphoric acid present within the pores of the COF is believed to result in improved conductivity. However, the amount of phosphoric acid loaded into a covalent organic framework may be varied depending on the conductivity requirement of the membrane. A skilled person will appreciate that phosphoric acid loading is not the only factor that will affect conductivity of a membrane according to the invention and other factors, such as topology, may also be relevant. In some embodiments of the invention that may be mentioned herein, the non-proton conducting covalent organic framework may have a conductivity of less than 10 -11 S cm –1 . The maximum possible loading of phosphoric acid is determined by the pore volume. In some embodiments of the invention that may be mentioned herein, the weight ratio of covalent organic framework to phosphoric acid may be from 10:1 to 1:3. In some embodiments of the invention that may be mentioned herein, the COFs may have a geometry selected from the group consisting of hexagonal, tetragonal, trigonal and kagome. Without being bound by theory, the different geometries allow modification of the COFs to provide desired properties. In some embodiments of the invention that may be mentioned herein, the proton-conducting membrane may have a conductivity of at least 10 -2 S cm -1 , such as at least 10 -1 S cm -1 . In embodiments of the invention that may be mentioned herein, the covalent organic framework may comprise a substructure selected from the following a) to k): ;
, where the dashed lines may represent points of attachment to the rest of the covalent organic framework, and wherein in each of a) to k), R, R 1 , R 2 , R 3 , and R 4 may be each independently selected from the group consisting of H, -OH, -OR, -R, -X and -(OCH 2 ) z OCH 3 , wherein R may represent a C 1-3 alkyl group; X may represent F, Cl or Br; and z may represent an integer of from 1 to 10. Unless otherwise stated, the term “alkyl” refers to an unbranched or branched, cyclic, saturated or unsaturated (so forming, for example, an alkenyl or alkynyl) hydrocarbyl radical, which may be substituted or unsubstituted (with, for example, one or more halo atoms). In some embodiments of the invention that may be mentioned herein, R, R 1 , R 2 , R 3 , and R 4 may be each independently selected from the group consisting of H, -OH, -OMe, -Me, -F, -Br and -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option a) applies and either: (i) R 1 and R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 represents H and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iii) R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 and R 2 represents H. In further embodiments of the invention that may be mentioned herein, wherein option b) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option c) applies and R represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option d) applies and either: (i) R 1 -R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 2 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 2 -R 3 represent H, and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iv) R 1 and R 3 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option e) applies and either: (i) R 1 -R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 2 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 2 -R 3 represent H, and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iv) R 1 and R 3 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option f) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 2 and R 3 represent H, and R 1 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iii) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option g) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option h) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option i) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option j) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 1 -R 3 represent H, and R 4 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iii) R 1 , R 2 and R 4 represent H, and R 3 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (iv) R 1 , R 3 and R 4 represent H, and R 2 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (v) R 2 -R 4 represent H; and R 1 represents H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vi) R 3 -R 4 represent H, and R 1 -R 2 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (vii) R 1 and R 2 represent H, and R 3 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (viii) R 1 and R 3 represent H, and R 2 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (ix) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In further embodiments of the invention that may be mentioned herein, wherein option k) applies and either: (i) R 1 -R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; (ii) R 2 and R 3 represent H, and R 1 and R 4 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 ; or (iii) R 1 and R 4 represent H, and R 2 and R 3 represent H, -OH, -OMe, -Me, -F, -Br or -(OCH 2 ) z OCH 3 . In a second aspect of the invention, there is provided a covalent organic framework as defined in any one of options a) to k) above, provided that the covalent organic framework is not
where each of Ri to R4 represent H.
In a third aspect of the invention, there is provided a proton exchange membrane fuel cell comprising a proton-conducting membrane as defined above.
As will be appreciated, the present disclosure provides the following advantages.
1. Easy preparation of COFs at large scale: COFs can be synthesized by solvothermal conditions, with simple reaction systems of common organic solvents, acetic acid and monomers, as described in the following examples. The COF products can be purified by simple washing with organic solvents to give a high yield.
2. Easy process for manufacturing of phosphoric acid-COF hybrids: a physical mixture of COFs with phosphoric acid enables the preparation of hybrids quantitatively; no further purification is required for application. 3. Easy to fabricate phosphoric acid-COFs hybrids membrane: the membrane can be prepared by pressing the hybrid powder, and the size and thickness of membrane can be user-designed. The resulting membranes may be kept under dry inert atmosphere.
As also will be appreciated, the present disclosure overcomes existing catalyst stability and activity problems such as avoiding anode/cathode poisoning effects and enabling high-rate proton conduction over a wide range of temperatures. Further, the present disclosure provides a series of COFs with tunable geometries, porosity, and thermal and chemical stability. These COFs offer large enough space for proton carrier immobilization. The proton carrier can form stable hydrogen-bonding network to enable fast proton transport.
Further aspects and embodiments of the invention will now be discussed by reference to the following non-limiting examples.
Examples
Materials
Starting materials were sourced from commercial suppliers, such as Sigma Aldrich and the like.
Analytical techniques
FTIR spectroscopy
FTIR spectra were recorded on a Bruker ALPHA FT-IR model OPUS Spectroscopy Software infrared spectrometer using KBr pellets.
X-ray diffraction (XRD)
XRD data were recorded on a Bruker D8 ADVANCE diffractometer with a Cu/Ka anode (A = 1.5406 A) by depositing powder on PMMA powder specimen holder, from 20 = 0.5° up to 30° with 0.02° increment.
Nitrogen-sorption isotherm measurements
Nitrogen sorption isotherms were measured at 77 K with a Micromeritics Instrument Corporation model 3Flex surface characterization analyzer. The Brunauer-Emmett-Teller (BET) method was utilized to calculate the specific surface areas. By using the density functional theory model, the pore volume was derived from the sorption curve. SEM and EDS SEM and EDS images were recorded on a JEOL-JSM6701F Field Emission Scanning Electron Microscope with an accelerating voltage of 5 kV at a working distance of 8.0 mm. EDS was carried out with an accelerating voltage of 15 kV. Samples were dispersed in tetrahydrofuran (THF) and sonicated for 60 seconds before being drop-casted onto a silicon wafer and coated with Pt with a sputter coater at ambient temperature (298 K) under vacuum prior to SEM analysis. TGA TGA data was collected using a TA Instruments Q500 by heating the samples from 30 °C to 800 °C at a rate of 10 °C/min under nitrogen flow (10 mL/min). Solid-state nuclear magnetic resonance (NMR) spectroscopy Solid-state NMR experiments were completed on a 14.1 T Bruker Advance III HD 600 MHz spectrometer, using a 1.9 mm Bruker HXY probe at an MAS frequency of 24 kHz (20 kHz for variable temperature measurements). All spectra were processed using the Topspin software package and referenced to the unified scale using IUPAC recommended frequency ratios relative to the 13 C adamantane (s) methylene resonance (δ = 37.77 ppm) (B. Febriansyah et al., Mater. Horiz.2023, 10, 536-546). Spectral deconvolution was performed with dmfit (D. Massiot et al., Magn. Reson. Chem.2002, 40, 70-76). Example 1. General method for preparation of COFs A mixture of solvents with suitable component and ratio, such as dioxane, mesitylene, o- dichlorobenzene (o-DCB), n-butanol (n-BuOH), cyclohexane, benzenitrile, nitrobenzene, methylcyclohexane, chlorocyslohexane, p-xylene, o-xylene, m-xylene, propanol, isopropanol, benzyl alcohol, methanol, ethanol, pentanol, 1-hexanol, anisole, hexane, tetrahydrofuran (THF), chloroform, toluene, dichloroethylene, dimethylformamide, diethylformamide, dimethylacetamide, chlorobenzene, N-methylpyrrolidone, dimethyl sulfoxide, m-cresol, and 1,2-dichloroethane, was used as the solvent in polymerization. An acid, such as acetic acid, trifluoracetic acid, p-tolunensulfonyl acid, and Lewis catalyst (BF 3 ^OEt 2 , Sc(OTf) 3 , metal nitrate, and metal oxides), of different concentrations was used as a catalyst. The mixture of monomers with catalyst in solvent was kept at different temperatures to enable polymerization. After certain periods of 1-15 days, the precipitate was collected by filtration and washed with solvents such as THF, dichloromethane, chloroform, dimethylformamide, and acetone. The resulting products were dried under vacuum and kept under inert atomosphere. Example 2. Synthesis of 5'-(4-aminophenyl)-[1,1':3',1''-terphenyl]-4,4''-diamine (TPB)- 2,2',5,5'-tetramethoxy-[1,1'-biphenyl]-4,4'-dicarbaldehyde (TMBPDA)-COF TPB (knot, 15 mg) and TMBPDA (21.1 mg) were dissolved in p-xylene and n-BuOH (1 mL, volume ratio from 1:1 to 3:1) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed, and heated at 90 °C for 7 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and Soxhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give TPB-TMBPDA-COF as a yellow solid in 81% yield. TPB-TMBPDA-COF was kept under dry inert atmosphere. Example 3. Synthesis of TPB-TRBPDA-COFs Monomer 1: TPB (knot name) Monomer 2: TRBPDA (linker name), R = –H, –OMe, –Me, –OH, –F, –Br, or –(OCH 2 ) X OCH 3 (X = 1-20) The protocol in Example 2 is applicable for the preparation of TPB-TMeBPDA-COFs,TPB- BPDA-COFs, TPB-THyBPDA-COFs, TPBTFBPDA-COFs, TPB-TBrBPDA-COFs, TPB- TEoBPDA-COFs, TPB-2,2’-DMeBPDA-COFs,TPB-2,2’-DPDA-COFs, TPB-2,2’-DHyBPDA- COFs, TPB-2,2’-DFBPDA-COFs, TPB-2,2’-DBrBPDA-COFs, TPB-2,2’-DEoBPDA-COFs, TPB-3,3’-DMeBPDA-COFs,TPB-3,3’-DPDA-COFs, TPB-3,3’-DHyBPDA-COFs, TPB-3,3’- DFBPDA-COFs, TPB-3,3’-DBrBPDACOFs, and TPB-3,3’-DEoBPDA-COFs. The synthesis of TPB-TRBPDA-COFs is similar to TPB-TMBPDA-COF by replacing –OMe substituted linker with the one substituted with –Me, –H, –OH, –F, –Br, and –(OCH 2 ) X OCH 3 . Example 4. Synthesis of TPB-DMTP-COF Monomers of TPB (28.1 mg) and DMTP (23.3 mg) were added into a 10-mL Pyrex tube which contained 1 mL o-DCB/n-BuOH (1:1 by volume (vol.)) mixture, followed by introducing acetic acid (0.1 mL, 6 M). The Pyrex tube was degassed via three freeze-pump-thaw cycles, sealed under vacuum, and kept at 120 °C for 72 h. The precipitate was collected by centrifugation and washed with THF (5 × 10 mL) before Soxhlet extraction with THF for 24 h at 100 °C. The powder was collected and dried at 120 °C under vacuum overnight to give TPB-DMTP-COF in 83% isolated yield. TPB-DMTP-COF was kept under dry inert atmosphere. Example 5. Synthesis of TPB-DRTP-COFs Monomer 1: TPB (knot name) Monomer 2: DMTP (linker name), R = –H, –OMe, –Me, –OH, –F, –Br, or –(OCH 2 ) X OCH 3 (X = 1-20) The protocol in Example 4 is applicable for the preparation of TPB-TP-COFs, TPB-DMeTP- COFs, TPB-DHyTP-COFs, TPB-DFTP-COFs, TPB-DBrTP-COFs, TPB-DEoTP-COFs, TPB- TMeTP-COFs, TPB-THyTP-COFs, TPB-TFTP-COFs, TPB-TBrTP-COFs, TPB-TEoTP-COFs, TPB-MeTP-COFs, TPB-HyTP-COFs, TPB-FTP-COFs, TPB-BrTP-COFs, and TPB-EoTP- COFs. The synthesis of TPB-DRTP-COFs is similar to TPB-DMTP-COF by replacing –OMe substituted linker with the one substituted with –Me, –H, –OH, –F, –Br, and –(OCH 2 ) X OCH 3 . Example 6. Synthesis of TPB-2,2''',5,5'''-tetramethoxy-[1,1':4',1'':4'',1'''-quaterp henyl]- 4,4'''-dicarbaldehyde (TMQPDA)-COF TPB-TMQPDA-COF was synthesized by analogy to the other materials made herein. Example 7. Synthesis of TPB-2,5-dimethylterephthalaldehyde (DMeTP)-COF Monomers of TPB (32.7 mg) and DMeTP (22.8 mg) were added into a 10-mL Pyrex tube which contained 1 mL o-DCB/n-BuOH (1:1 by vol.) mixture, followed by introducing acetic acid (0.1 mL, 6 M). The Pyrex tube was degassed via three freeze-pump-thaw cycles, sealed under vacuum, and kept at 120 °C for 72 h. The precipitate was collected by centrifugation and washed with THF (5 × 10 mL) before Soxhlet extraction with THF for 24 h. The powder was collected and dried at 120 °C under vacuum overnight to give TPB-DMeTP COF in 89% isolated yield. Example 8. Synthesis of 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (TTA)-4,4',4''-(1,3,5- triazine-2,4,6-triyl)tribenzaldehyde (TTB)-COF TTA (15 mg) and TTB (16.6 mg) were dissolved in a mixture of mesitylene and 1,4-dioxane (1:1 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 120 °C for 3 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and Soxhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give TTA-TTB-COF as a yellow solid in 78% yield. TTA-TTB -COF was kept under dry inert atmosphere. Example 9. Synthesis of TTRA-TTRB-COFs Monomer 1: TTRA (knot name) Monomer 2: TTRB (linker name), R = –H, –OMe, –Me, –OH, –F, –Br, or –(OCH 2 ) X OCH 3 (X = 1-20) The protocol in Example 8 is applicable for the preparation of TTAOMe-TTBOMe-COF, TTAMe-TTBMe-COF, TTAH-TTBH-COF, TTAFTTBF-COF, TTABr-TTBBr-COF, TTADOMe- TTBDOMe-COF, TTADMe-TTBDMe-COF, TTADH-TTBDH-COF, TTADFTTBDF-COF, TTADBr-TTBDBr-COF, TTATOMe-TTBTOMe-COF, TTATMe-TTBTMe-COF, TTATH- TTBTH-COF, TTATFTTBTF-COF, TTATBr-TTBTBr-COF, TTAQOMe-TTBQOMe-COF, TTAQMe-TTBQMe-COF, TTAQH-TTBQH-COF, TTAQF-TTBQF-COF, TTAQBr-TTBQBr- COF, TTAOMe-TTBDOMe-COF, TTAMe-TTBDMe-COF, TTAH-TTBDH-COF, TTAF-TTBDF- COF, TTABr-TTBDBr-COF, TTAOMe-TTBTOMe-COF, TTAMe-TTBTMe-COF, TTAH- TTBTH-COF, TTAFTTBTF-COF, TTABr-TTBTBr-COF, TTAOMe-TTBQOMe-COF, TTAMe- TTBQMe-COF, TTAH-TTBQH-COF, TTAFTTBQF-COF, TTABr-TTBQBr-COF, TTAMe- TTBDOMe-COF, TTAMe-TTBDMe-COF, TTAMe-TTBDH-COF, TTAMe-TTBDF-COF, TTAMe-TTBDBr-COF, TTAH-TTBTOMe-COF, TTAH-TTBTMe-COF, TTAH-TTBTH-COF, TTAH-TTBTFCOF, TTAH-TTBTBr-COF, TTAF-TTBQOMe-COF, TTAF-TTBQMe-COF, TTAF-TTBQH-COF, TTAF-TTBQF-COF, TTAFTTBQBr-COF, TTABr-TTBQOMe-COF, TTABr-TTBQMe-COF, TTABr-TTBQH-COF, TTABr-TTBQF-COF, and TTABr-TTBQBr-COF. The synthesis of TTRA-TTRB-COFs is similar to TTA-TTB-COF by replacing the –H substituted linker with the one substituted with –OMe, –Me, –OH, –F, and –Br. Example 10. Synthesis of TTA-benzene-1,3,5-tricarbaldehyde (TFB)-COF TTA (35.4 mg) and TFB (16.2 mg) were dissolved in a mixture of o-DCB and BuOH (1:1 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 120 °C for 3 days. The precipitate was collected by filtration, washed with THF (THF, 5 × 10 mL) and Soxhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give TPB-TFB-COF as a yellow solid in 78% yield. TTA-TFB-COF was kept under dry inert atmosphere. Example 11. Synthesis of TTA-TFRB-COFs Monomer 1: TTA (knot name) Monomer 2: TFRB (linker name), R = –H, –OMe, –Me, –OH, –F, –Br The protocol in Example 10 is applicable for the preparation of TTA-TFBOMe-COFs, TTA- TFBMe-COFs, TTA-TFBH-COFs, TTA-TFBFCOFs, TTA-TFBBr-COFs, TTA-TFBDOMe- COFs, TTA-TFBDMe-COFs, TTA-TFBDH-COFs, TTA-TFBDF-COFs, TTATFBDBr-COFs, TTA-TFBTOMe-COFs, TTA-TFBTMe-COFs, TTA-TFBTH-COFs, TTA-TFBTF-COFs, and TTA-TFBTBr-COFs. The synthesis of TTA-TFRB-COFs is similar to TTA-TFRB-COFs by replacing –H substituted linker with the one substituted with –OMe, –Me, –OH, –F, and –Br. Example 12. Synthesis of ACOF-1 Hydrazine hydrate (38 μL) and TFB (60 mg) were dissolved in a mixture of 1,4-dioxane (2 mL) and acetic acid (0.2 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze- pump-thaw, sealed and heated at 120 °C for 3 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and Soxhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give ACOF-1 as a pale yellow solid in 86% yield. ACOF-1 was kept under dry inert atmosphere. Example 13. Synthesis of ACOFs-R Monomer 1: TFB-R (knot name), R = = –H, –OMe, –Me, –OH, –F, –Br Monomer 2: Hydrazine (linker name) The protocol in Example 12 is applicable for the preparation of ACOF-OMe, ACOF-Me, ACOF- OH, ACOF-F, ACOF-Br, ACOF-DOMe, ACOF-DMe, ACOF-DOH, ACOF-DF, ACOF-DBr, ACOF-TOMe, ACOF-TMe, ACOF-TOH, ACOF-TF, and ACOF-TBr. The synthesis of ACOFs- R is similar to ACOF-1 by replacing H–substituted linker with the one substituted with –OMe, –Me, –OH, –F,and –Br. Example 14. Synthesis of Py-TMQPDA-COF 4,4',4'',4'''-(3a1,5-dihydropyrene-1,3,6,8-tetrayl)tetraanil ine (PyTTA, 15 mg) and TMQPDA (25.5 mg) were dissolved in 1 mL mixture of o-DCB and n-BuOH (2:3 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 90 °C for 3 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and Soxhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give Py-TMQPDA-COF as a yellow solid in 85% yield. Py-TMQPDA-COF was kept under dry inert atmosphere. Characterization Table 1. Atomistic coordinates of Py-TMQPDA-COF optimized by using the DFTB+ method. Space group: P6; a = 73.7023 Å, b = 73.7023 Å, c = 3.8227 Å; α = β =90˚, γ =120˚. Table 2. Atomistic coordinates for the refined unit cell parameters for Py-TMQPDA-COF via Pawley refinement. Space group: P6; a = 73.7021 Å, b = 73.7021 Å, c = 3.8327 Å; α = β =90˚, γ =120˚. Rwp = 3.43%, Rp = 2.88%.
Example 15. Synthesis of Py-TRQPDA-COFs
Monomer 1: PyTTA (knot name) Monomer 2: TRQPDA-COF (linker name), R = –H, –OMe, –Me, –OH, –F, –Br and – (OCH 2 ) X OCH 3 (X = 1-20) The protocol in Example 14 is applicable for the preparation of Py-TQPDA-COF(R 1 = R 4 = R 2 = R 3 = H), Py-TMeQPDA-COF(R 1 = R 4 = Me, R 2 = R 3 = H), Py-THQPDA-COF(R 1 = R 4 = OH, R 2 = R 3 = H), Py-TFQPDA-COF(R 1 = R 4 = F, R 2 = R 3 = H), Py-TBrQPDACOF(R 1 = R 4 = Br, R 2 = R 3 = H), Py-TEoQPDA-COF(R 1 = R 4 = Eo, R 2 = R 3 = H), Py-TMeQPDA-COF(R 1 = R 4 = H, R 2 = R 3 = Me), Py-THQPDA-COF(R 1 = R 4 = H or OH, R 2 = R 3 = OH), Py-TFQPDA-COF(R 1 = R 4 = H, R 2 = R 3 = F), Py-TBrQPDACOF(R 1 = R 4 = H, R 2 = R 3 = Br), Py-TEoQPDA-COF(R 1 = R 4 = H, R 2 = R 3 = Eo), Py-OQPDA-COF(R 1 = R 4 = R 2 = R 3 = H), Py-OMeQPDA-COF(R 1 = R 4 = R 2 = R 3 = Me), Py-OHQPDA-COF(R 1 = R 4 = R 2 = R 3 = OH), Py-OFQPDA-COF(R 1 = R 4 = R 2 = R 3 = F), Py-OBrQPDA-COF(R 1 = R 4 = R 2 = R 3 = Br), and Py-TEoQPDA-COF(R 1 = R 4 = R 2 = R 3 = Eo). The synthesis of Py-TRQPDA-COFs is similar to Py-TMQPDA-COF by replacing –H substituted linker with the one substituted with –OMe, –Me, –OH, –F, –Br and – (OCH 2 ) X OCH 3 . Example 16. Synthesis of Py-2,2’-BPyPh-COFs PyTTA (11.3 mg) and 2,2’-BPyPh (8.5 mg) were dissolved in 1 mL mixture of mesitylene and 1,4-dioxane (1:1 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 120 °C for 3 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and SoXhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give Py-2,2’-BPyPh-COFs as a pale red solid in 76% yield. Py-2,2’-BPyPh-COFs was kept under dry inert atmosphere. Example 17. Synthesis of Py-2,2’-BPyPhR-COFs Monomer 1: PyTTA (knot name) Monomer 2: 2,2-BPyPhR (linker name), R = –H, –OMe, –Me, –OH, –F, –Br and – (OCH 2 ) X OCH 3 (X = 1-20) The protocol in Example 16 is applicable for the preparation of Py-2,2’-BPyPhQOMe-COFs, Py-2,2’-BPyPhQMe-COFs, Py-2,2’-BPyPhQHCOFs, Py-2,2’-BPyPhQF-COFs, Py-2,2’- BPyPhQBr-COFs, Py-2,2’-BPyPhQEo-COFs, Py-2,2’-BPyPhDOMe-COFs, Py-2,2’- BPyPhDMe-COFs, Py-2,2’-BPyPhDH-COFs, Py-2,2’-BPyPhDF-COFs, Py-2,2’-BPyPhDBr- COFs, and Py-2,2’-BPyPhDEo-COFs. The synthesis of Py-2,2’-BPyPhR-COFs is similar to Py-2,2’-BPyPh-COFs by replacing H-substituted linker with the one substituted with –OMe, – Me, –OH, –F, –Br and –(OCH 2 ) X OCH 3 . Example 18. Synthesis of Py-DMTP-COFs PyTTA (15 mg) and DMTP (25.5 mg) were dissolved in 1 mL mixture of o-DCB and n-BuOH (2:3 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 90 °C for 3 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and SoXhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give Py-DMTP-COF as an orange solid in 85% yield. Py-DMTP-COF was kept under dry inert atomosphere. Example 19. Synthesis of Py-DRTP-COFs Monomer 1: PyTTA (knot name) Monomer 2: DRTP (linker name), R = H, OMe, Me, OH, F, Br The protocol in Example 18 is applicable for the preparation of Py-TP-COF ,Py-DMTP-COF, Py-DMeTP-COF, Py-DHTP-COF, Py-DFTPCOF, Py-DBrTP-COF, Py-QMTP-COF, Py- QMeTP-COF, Py-QHTP-COF, Py-QFTP-COF, Py-QBrTP-COF, Py-TMTPCOF, Py-TMeTP- COF, Py-THTP-COF, Py-TFTP-COF, and Py-TBrTP-COF. The synthesis of TPB-TRBPDA- COFs is similar to TPB-TRBPDA-COF by MeO–substituted linker with the one substituted with–Me, –OH, –F, –Br and –(OCH 2 ) X OCH 3 . Example 20. Synthesis of Py-2,2''',5,5'''-tetramethoxy-[1,1':4',1'':4'',1'''-quaterph enyl]- 4,4'''-dicarbaldehyde (TMQPDA)-COF PyTTA (knot, 15 mg) and TMQPDA (linker, R 1 = R 4 = OMe, R 2 = R 3 = H, 25.5 mg) were dissolved in a mixture of o-DCB and n-BuOH (volume ratio of 2 to 3) and acetic acid (0.1 mL) in a 10X-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 90 °C for 3 days. The precipitate was collected by filtration, washed with THF (5 ×10 mL) and Sohexlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give Py-TMQPDA-COF as a yellow solid in 85% yield. Py-TMQPDA-COF was kept under dry inert atomosphere. This protocol is applicable for the preparation of Py-TQPDA-COF(R 1 = R 4 = R 2 = R 3 = H), Py- TMeQPDA-COF(R 1 = R 4 = Me, R 2 = R 3 = H), Py-THQPDA-COF(R 1 = R 4 = OH, R 2 = R 3 = H), Py-TFQPDA-COF(R 1 = R 4 = F, R 2 = R 3 = H), Py-TBrQPDA-COF(R 1 = R 4 = Br, R 2 = R 3 = H), Py-TEoQPDA-COF(R 1 = R 4 = Eo, R 2 = R 3 = H), Py-TMeQPDA-COF(R 1 = R 4 = H, R 2 = R 3 = Me), Py-THQPDA-COF(R 1 = R 4 = H OH, R 2 = R 3 = OH), Py-TFQPDA-COF(R 1 = R 4 = H, R 2 = R 3 = F), Py-TBrQPDA-COF(R 1 = R 4 = H, R 2 = R 3 = Br), Py-TEoQPDA-COF(R 1 = R 4 = H, R 2 = R 3 = Eo), Py-OQPDA-COF(R 1 = R 4 = R 2 = R 3 = H), Py-OMeQPDA-COF(R 1 = R 4 = R 2 = R 3 = Me), Py-OHQPDA-COF(R 1 = R 4 = R 2 = R 3 = OH), Py-OFQPDA-COF(R 1 = R 4 = R 2 = R 3 = F), Py-OBrQPDA-COF(R 1 = R 4 = R 2 = R 3 = Br), and Py-TEoQPDA-COF(R 1 = R 4 = R 2 = R 3 = Eo) . The synthesis of Py-TRQPDA-COFs is similar to Py-TMQPDA-COF by replacing –H substituted linker with the one substituted with –OMe, –Me, –OH, –F, –Br and –(OCH 2 ) X OCH 3 . Example 21. Synthesis of TFBCz-PDA-COFs TFBCz (37 mg) and benzene-1,4-diamine (PDA, 18 mg) were dissolved in 1 mL mixture of mesitylene and 1,4-dioxane (1:1 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 120 °C for 3 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and SoXhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give TFBCz- PDA-COFs as a yellow solid in 76% yield. TFBCz-PDA-COFs was kept under dry inert atmosphere. Example 22. Synthesis of TFBCz-RPDA-COFs Monomer 1: TFBCz (knot name) Monomer 2: RPDA (linker name), R = –H, –OMe, –Me, –OH, –F, –Br The protocol in Example 21 is applicable for the preparation of TFBCz-MPDA-COFs, TFBCz- MePDA-COFs, TFBCz-HPDA-COFs, TFBCz-FPDA-COFs, TFBCz-BrPDA-COFs, TFBCz- DMPDA-COFs, TFBCz-DMePDA-COFs, TFBCz-DHPDA-COFs, TFBCz-DFPDA-COFs, TFBCz-DBrPDA-COFs, TFBCz-TMPDA-COFs, TFBCz-TMePDA-COFs, TFBCz-THPDA- COFs, TFBCz-TFPDA-COFs, TFBCz-TBrPDA-COFs, TFBCz-QMPDA-COFs, TFBCz- QMePDA-COFs, TFBCz-QHPDA-COFs, TFBCz-QFPDA-COFs, and TFBCz-QBrPDA-COFs. The synthesis of TFBCz-RPDA-COFs is similar to TFBCz-PDA-COFs by replacing H substituted linker with the one substituted with –OMe, –Me, –OH, –F, and –Br. Example 23. Synthesis of HFPTP-PDA-COF HFPTP (20 mg) and PDA (14 mg) were dissolved in 1 mL mixture of o-DCB and n-BuOH (1:1 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 120 °C for 5 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and Soxhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give HFPTP-PDA-COF as a yellow solid in 84% yield. HFPTP-PDA-COF was kept under dry inert atmosphere. Example 24. Synthesis of HFPTP-RPDA-COFs Monomer 1: HFPTP (knot name) Monomer 2: RPDA (linker name), R = –H, –OMe, –Me, –OH, –F, –Br The protocol in Example 23 is applicable for the preparation of HFPTP-MPDA-COFs, HFPTP- MePDA-COFs, HFPTP-HPDA-COFs, HFPTPFPDA-COFs, HFPTP-BrPDA-COFs, HFPTP- DMPDA-COFs, HFPTP-DMePDA-COFs, HFPTP-DHPDA-COFs, HFPTPDFPDA-COFs, HFPTP-DBrPDA-COFs, HFPTP-TMPDA-COFs, HFPTP-TMePDA-COFs, HFPTP-THPDA- COFs, HFPTPTFPDA-COFs, HFPTP-TBrPDA-COFs, HFPTP-QMPDA-COFs, HFPTP- QMePDA-COFs, HFPTP-QHPDA-COFs, HFPTP-QFPDA-COFs, and HFPTP-QBrPDA-COFs. The synthesis of HFPTP-RPDA-COF is similar to HFPTP-PDA-COF by replacing H substituted linker with the one substituted with –OMe, –Me, –OH, –F, and –Br. Example 25. Synthesis of HFPTP-BPDA-COF HFPTP (20 mg) and RBPDA (13 mg) were dissolved in 1 mL mixture of o-DCB and n-BuOH (1:1 by vol.) and acetic acid (0.1 mL, 6 M) in a 10-mL vial. The vial was degassed by three cycles of freeze-pump-thaw, sealed and heated at 120 °C for 5 days. The precipitate was collected by filtration, washed with THF (5 × 10 mL) and Soxhlet with THF at 100 °C for 24 h. The solid was collected and dried under vacuum to give HFPTP-BPDA-COF as a yellow solid in 84% yield. HFPTP-BPDA-COF was kept under dry inert atmosphere. Example 26. Synthesis of HFPTP-RBPDA-COFs Monomer 1: HFPTP (knot name) Monomer 2: RBPDA (linker name), R = –H, –OMe, –Me, –OH, –F, –Br The protocol in Example 25 is applicable for the preparation of HFPTP-MeBPDA-COF, HFPTP-OMeBPDA-COF, HFPTP-HBPDA-COF, HFPTP-FBPDA-COF, HFPTP-BrBPDA- COF, HFPTP-DMeBPDA-COF, HFPTP-DOMeBPDA-COF, HFPTP-DHBPDACOF, HFPTP- DFBPDA-COF, HFPTP-DBrBPDA-COF, HFPTP-TMeBPDA-COF, HFPTP-TOMeBPDA-COF, HFPTPTHBPDA-COF, HFPTP-TFBPDA-COF, HFPTP-TBrBPDA-COF, HFPTP-QMeBPDA- COF, HFPTP-QOMeBPDA-COF, HFPTP-QHBPDA-COF, HFPTP-QFBPDA-COF, and HFPTP-QBrBPDA-COF. The synthesis of TPB-TRBPDA-COFs is similar to TPB-TRBPDA- COF by replacing H–substituted linker with the one substituted with –OMe, –Me, –OH, –F, and –Br. Example 27. General method for preparation of phosphoric acid-COFs hybrids Neat H 3 PO 4 was impregnated into COF via vacuum assisted method as shown in examples below. Neat phosphoric acid of different amounts was dissolved in anhydrous THF to form a homogeneous solution. The solution was injected using a syringe into a vial containing COF solid and the resulting mixture was stirred at room temperature for 3 h. The mixture was heated at 70 °C and evaporated under vacuum to remove THF over a period of 6 h, and kept at 70 °C for 12 h. The resulting powder was collected to produce phosphoric acid-COF hybrids quantitatively, which were kept under dry inert atmosphere. Example 28. Synthesis of phosphoric acid-TPB-TMBPDA-COFs hybrids Neat phosphoric acid (239.8 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into TPB-TMBPDA-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6 h, and kept at 70^°C for 12 h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 239.7 wt% as a black-colored solid, which was kept under dry inert atmosphere. Different phosphoric acid-TPB-TRBPDA-COFs-COF hybrids with different contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 29. Preparation of phosphoric acid-TPB-DMTP-COFs hybrid Neat phosphoric acid (211.2 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into TPB-DMTP-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 211 wt% as a black-colored solid, which was kept under dry inert atmosphere. Half filled phosphoric acid in phosphoric acid-TPB-DMTP-COFs-COF hybrids (105.6 wt%) were prepared using the same protocol. Example 30. Preparation of phosphoric acid-TPB-DMeTP-COFs hybrid Neat phosphoric acid (293 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into TPB-DMeTP-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6 h, and kept at 70^°C for 12 h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 292.8 wt% as a black-colored solid, which was kept under dry inert atmosphere. The phosphoric acid loading contents in phosphoric acid-TPB-DMeTP-COFs-COF hybrids can change from 0 wt% to 43.92 wt%, 87.84 wt%, 146.4 wt%, 175.68 wt%, 204.96 wt%, 234.24 wt% and 292.8 wt%. Different phosphoric acid-TPB-DMeTP-COFs-COF hybrids with different contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 31. Preparation of phosphoric acid-TTA-TTB-COFs hybrid Neat phosphoric acid (170.2 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into TTA-TTB-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 170.1 wt% as a black-colored solid, which was kept under dry inert atmosphere. Different phosphoric acid-TTRA-TTRB-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 32. Preparation of phosphoric acid-TTA-TFB-COFs hybrid Neat phosphoric acid (111.7 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into TTA-TFB-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 111.6 wt% as a pale brown-colored solid, which was kept under dry inert atmosphere. Different phosphoric acid-TTA-TFRB-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 33. Preparation of phosphoric acid-ACOF-1 hybrid Neat phosphoric acid (75.1 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into ACOF-1 (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 75.03 wt% as a pale brown-colored solid, which was kept under dry inert atmosphere. The phosphoric acid loading contents in phosphoric acid-ACOF-1 hybrids can change from 0 wt% to 11.25 wt%, 22.51 wt%, 37.52 wt%, 45.02 wt%, 52.52 wt%, 60.02 wt% and 75.03 wt%. Different phosphoric acid-ACOF-1 hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 34. Preparation of phosphoric acid-Py-TMQPDA-COFs hybrid Neat phosphoric acid (223.3 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into Py-TMQPDA-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 223.2 wt% as a black-colored solid, which was kept under dry inert atmosphere. Different phosphoric acid-Py-TRQPDA-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 35. Preparation of phosphoric acid-Py-2,2’-BPyPhR-COFs hybrid Neat phosphoric acid (142.8 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into Py-2,2’-BPyPhR-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 142.74 wt% as a black-colored solid, which was kept under dry inert atmosphere. The phosphoric acid contents in phosphoric acid-Py-2,2’-BPyPhR-COF hybrids can change from 0 wt% to 21.41 wt%, 42.82 wt%, 71.37 wt%, 85.64 wt%, 99.92 wt%, 114.19 wt% and 142.74 wt%. Different phosphoric acid-Py-2,2’-BPyPhR-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 36. Preparation of phosphoric acid-Py-DMTP-COFs hybrid Neat phosphoric acid (226.4 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into Py-DMTP-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 226.3 wt% as a black-colored solid, which was kept under dry inert atmosphere. Different phosphoric acid-Py-DRTP-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 37. Preparation of phosphoric acid-TFBCz-PDA-COFs hybrid Neat phosphoric acid (124.5 mg) ws dissolved in anhydrous THF (4 mL). The solution was injected into TFBCz-PDA-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6 h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 124.4 wt% as a brown solid, which was kept under dry inert atmosphere. Different phosphoric acid-TFBCz-RPDA-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 38. Preparation of phosphoric acid-HFPTP-RPDA-COFs hybrid Neat phosphoric acid (58.6 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into HFPTP-PDA-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6 h, and kept at 70^°C for 12 h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 58.5 wt% as a pale brown-colored solid, which was kept under dry inert atmosphere. Different phosphoric acid-HFPTP-RPDA-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 39. Preparation of phosphoric acid-HFPTP-BPDA-COFs hybrid Neat phosphoric acid (87.9 mg) was dissolved in anhydrous THF (4 mL). The solution was injected into HFPTP-BPDA-COFs (100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12^h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 87.8 wt% as a black-colored solid, which was kept under dry inert atmosphere. The phosphoric acid loading contents in phosphoric acid-HFPTP-BPDA-COFs hybrids can change from 0 wt% to 13.17 wt%, 26.35 wt%, 43.92 wt%, 52.70 wt%, 61.49 wt%, 70.27 wt% and 87.8 wt%. Different phosphoric acid-HFPTP-RBPDA-COFs hybrids with different loading contents of phosphoric acid were prepared by using different amounts of neat phosphoric acid in the protocol. Example 40. Preparation of phosphoric acid-TPB-TMQPDA-COFs hybrid Neat phosphoric acid (157.6 mg) was dissolved in anhydrous THF (4 mL). The solution was injected to TPB-TMQPDA-COFs (R = –H, 100 mg) in a vial (10 mL) with a syringe and the mixture was stirred at room temperature for 3 h. The mixture was heated at 70^°C and evaporated under vacuum to remove THF over a period of 6^h, and kept at 70^°C for 12 h. The resulting powder was collected to yield quantitatively phosphoric acid-COF hybrid with phosphoric acid content of 157.1 wt% as a pale brown-colored solid, which was kept under dry inert atmosphere. Example 41. General method for preparation of membranes The ground hybrid sample was transferred to a mould with dies of different diameters, sandwiched between two steel plates, and pressed at 100 kN for 30 to 60 min under nitrogen to form membranes. Different weights of hybrid samples enable to prepare membranes of different thickness. The membranes were kept under dry inert atmosphere. Size and thickness of membranes and control The membrane size is determined by a mould with a standard die of different diameters. The thickness can be adjusted by the mass of material added into the mould. Usually, with increasing mass of COFs hybrids, the thickness of the membrane increases. Example 42. Synthesis of phosphoric acid-TPB-DRTP-COFs hybrid membranes Preparation of phosphoric acid-TPB-TRBPDA-COF (R = –OMe, phosphoric acid-TPB- TMBPDA-COFs) hybrid membranes The ground phosphoric acid-TPB-TMBPDA-COF hybrid sample (200 mg) was transferred to a mould with a die of diameter 1 cm (highly changeable), sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.80 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.8 to 2 mm. The resulting membranes can be kept under dry inert atmosphere. Example 43. Synthesis of phosphoric acid-TPB-DRTP-COFs hybrid membranes Preparation of phosphoric acid-TPB-DRTP-COFs (R = –Me, phosphoric acid-TPB-DMeTP- COFs) hybrid membranes The ground phosphoric acid-TPB-DMeTP-COFs hybrid sample (200 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.95 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.9 to 2 mm. The resulting membranes can be kept under dry inert atmosphere. Example 44. Synthesis of phosphoric acid-TTRA-TTRB-COFs hybrid membranes Preparation of phosphoric acid-TTRA-TTRB-COFs (R = –H, phosphoric acid-TTA-TTB-COFs) hybrid membranes The ground phosphoric acid-TTA-TTB-COFs hybrid sample (150 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.40 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.78 to 1.5 mm. The resulting membranes can be kept under dry inert atmosphere. Example 45. Synthesis of phosphoric acid-TTA-TFRB-COFs hybrid membranes Preparation of phosphoric acid-TTA-TFRB-COFs (R = –H, phosphoric acid-TTA-TFB-COFs) hybrid membranes The ground phosphoric acid-TTA-TFB-COFs hybrid sample (150 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.56 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0. 8 to 1.6 mm. The resulting membranes can be kept under dry inert atmosphere. Example 46. Synthesis of phosphoric acid-ACOFs hybrid membranes Preparation of phosphoric acid-ACOFs (R = –H, phosphoric acid-ACOF-1) hybrid membranes The ground phosphoric acid-ACOF-1 hybrid sample (200 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.75 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.88 to 1.8 mm. The resulting membranes can be kept under dry inert atmosphere. Example 47. Synthesis of phosphoric acid-Py-TRQPDA-COFs hybrid membranes Preparation of phosphoric acid-Py-TRQPDA-COFs (R = –OMe, phosphoric acid-Py- TMQPDA-COFs) hybrid membranes The ground phosphoric acid-Py-TMQPDA-COFs hybrid sample (200 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.80 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.98 to 1.9 mm. The resulting membranes can be kept under dry inert atmosphere. Example 48. Synthesis of phosphoric acid-Py-2,2’-BPyPhR-COFs hybrid membranes Preparation of phosphoric acid-Py-Py-2,2’-BPyPhR-COFs (R = –H, phosphoric acid-Py-Py- 2,2’-BPyPh-COFs) hybrid membranes The ground phosphoric acid-Py-2,2’-BPyPh-COFs hybrid sample (150 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.35 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.78 to 1.5 mm. The resulting membranes can be kept under dry inert atmosphere. Example 49. Synthesis of phosphoric acid-Py-DRTP-COFs hybrid membranes Preparation of phosphoric acid- Py-DRTP-COF (R = –OMe, phosphoric acid-Py-DMTP-COF) hybrid membranes The ground phosphoric acid-Py-DMTP-COF hybrid sample (140 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.34 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.88 to 1.5 mm. The resulting membranes can be kept under dry inert atmosphere. Example 50. Synthesis of phosphoric acid-TFBCz-RPDA-COFs hybrid membranes Preparation of phosphoric acid-TFBCz-RPDA-COFs (R = –H, phosphoric acid-TFBCz-PDA- COFs) hybrid membranes The ground phosphoric acid-TFBCz-PDA-COFs hybrid sample (170 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.56 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.98 to 1.6 mm. The resulting membranes can be kept under dry inert atmosphere. Example 51. Synthesis of phosphoric acid-HFPTP-RPDA-COFs hybrid membranes Preparation of phosphoric acid-HFPTP-RPDA-COFs (R = –H, phosphoric acid-HFPTP-PDA- COFs) hybrid membranes The ground phosphoric acid-HFPTP-PDA-COFs hybrid sample (130 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.18 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.89 to 1.3 mm. The resulting membranes can be kept under dry inert atmosphere. Example 52. Synthesis of phosphoric acid-HFPTP-RBPDA-COFs hybrid membranes Preparation of phosphoric acid-HFPTP-RBPDA-COFs (R = –H, phosphoric acid-HFPTP- BPDA-COFs) hybrid membranes The ground phosphoric acid-HFPTP-BPDA-COFs hybrid sample (150 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.33 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.78 to 1.4 mm. The resulting membranes can be kept under dry inert atmosphere. Example 53. Synthesis of phosphoric acid-TPB-TMQPDA-COFs hybrid membranes Preparation of phosphoric acid-TPB-TMQPDA-COFs (R = –H, phosphoric acid- TMQPDA- COFs) hybrid membranes The ground phosphoric acid-TPB-TMQPDA-COFs hybrid sample (150 mg) was transferred to a mould with a die of diameter 1 cm, sandwiched between two steel plates, and pressed at 100 kN for 60 min under nitrogen to form a membrane of a thickness of 1.31 mm. Different weights of hybrid samples enable the preparation of membranes of different thickness ranging from 0.76 to 1.5 mm. The resulting membranes can be kept under dry inert atmosphere. Example 54. Characterization, design and crystal structures of COFs In the above examples, we synthesized 7 covalent organic frameworks (COFs) used as solid membrane. The targeted COFs were constructed to hold predesigned 1D channels with hexagonal shape, pore size and environment. PXRD pattern of newly-synthesized TPB-TMBPDA-COF revealed peaks at 2.28°, 4.02°, 4.60°, 6.12°, 8.08° and 23.08°, which were assigned to the (100), (110), (200), (210), (220) and (001) facets, respectively. We used density-functional based tight-binding (DFTB+) calculations to optimize the formation and configuration of stacking modes. The AA-stacking mode reproduces the PXRD peak position and intensity. The TPB-TMBPDA-COF adopts P 6 space group with unit-cell parameters of a = 44.7208 Å, b = 44.7208 Å, c = 3.8280 Å, α = β = 90° and γ = 120° (for atomistic coordinates, see Table 3). Table 3. Atomistic coordinates for the AA-stacking mode of TPB-TMBPDA-COF optimized by using the DFTB+ method. Space group: P6; a = 44.7208 Å, b = 44.7208 Å, c = 3.8280 Å. We conducted Pawley refinements and confirmed the correctness of the PXRD peak assignments, as indicated by a negligible difference with R WP = 4.64% and R P = 2.97%. Rietveld refinement also yields a P 6 space group (Table 4). The results show the unit cell and the stacking structure. The presence of (001) facet at 23.08° suggests an extended structural ordering with an interlayer interval of 3.83 Å along the z direction. By contrast, the AB stacking mode resulted in a PXRD pattern that largely deviates from that of the experimentally observed profile (Table 5). Therefore, TPB-TMBPDA-COF consists of an extended hexagonal lattice with dense mesoporous 1D channels. A steep N 2 uptake was observed in the low relative pressure region (P/P 0 < 0.01), followed by a sharp increase of the uptake, ranging from P/P 0 = 0.1 to 0.35, which indicate that the TPB-TMBPDA-COF exhibited a typical type IV isotherm sorption curve and is highly porous to achieve a BET surface area of 1657 m 2 g –1 , a pore size of 3.82 nm and an exceptional pore volume of 1.31 cm 3 g –1 (Table 6). The TPB-TMQPDA- COF revealed peaks at 2.06°, 3.50°, 3.76°, 4.96° and 6.38°, which were assigned to the (110), (020), (220), (330) and (001) facets, respectively. The AA-stacking mode reproduces the PXRD peak position and intensity. The TPB-TMQPDA-COF adopts P 3 space group with unit- cell parameters of a = 36.2764 Å, b = 33.0338 Å, c = 3.8296 Å, ^ = ^ = ^ = 90˚ (for atomistic coordinates, see Table 7). The Pawley refinements confirmed the correctness of the PXRD peak assignments, as indicated by a negligible difference with R WP = 5.82% and R P = 4.66% (Table 8). The results show the unit cell and the stacking structure. Therefore, Py-DMTP-COF consists of an extended 1D tetragonal lattice. The Py-DMTP-COF exhibited a reversible nitrogen sorption isotherm and is highly porous to achieve a BET surface area of 1442 m 2 g – 1 , a pore size of 1.80 nm and an pore volume of 1.23 cm 3 g –1 (Table 6). The TPB-DMeTP- COF, TPB-DMTP-COF, TTA-TTB-COF, TTA-TFB-COF and ACOF-1 displayed the same PXRD patterns as reported, adopting AA stacking structures (FIGS.3-7), and their porosities are listed in Table 6. Table 4. Atomistic coordinates for the refined unit cell parameters for TPB-TMBPDA-COF via Pawley refinement. Space group: P6; a = 44.4556 Å, b = 44.4556 Å, c = 3.9215 Å. Table 5. Atomistic coordinates for the AB-stacking mode of TPB-TMBPDA-COF optimized by using the DFTB+ method. Space group: P63; a = 44.6006 Å, b = 44.6006 Å, c = 8.1072 Å. Table 6. Porosity of COFs. Table 7. Atomistic coordinates of Py-DMTP-COF optimized by using the DFTB+ method. Space group: PMMN; a = 36.2764 Å, b = 33.0338 Å, c = 3.8296 Å; α = β = γ = 90˚. Table 8. Atomistic coordinates for the refined unit cell parameters for Py-DMTP-COF via Pawley refinement. Space group: PMMN; a = 37.7060 Å, b = 31.4016 Å, c = 3.8327 Å; α = β = γ = 90˚. Rwp = 5.82%, Rp = 4.66% All the COF samples exhibited distinct PXRD peaks to show long-range order of the resulting materials (FIG.1). Taking TPB-TMBPDA-COF as an example (FIG. 1a), the XRD peaks are located at 2.28°, 4.02°, 4.60°, 6.12°, 8.08° and 23.08°, which can be assigned to the (100), (110), (200), (210), (220) and (001) facts. This result indicates that TPB-TMBPDA-COF form layered frameworks with a pore size of 3.82 nm. Taking TPB-DMeTP-COF as an example (FIG.1b), the XRD peaks are located at 2.82°, 4.94°, 5.62°, 7.54°, 10.04° and 25.42°, which can be assigned to the (100), (110), (200), (210), (220) and (001) facts. This result indicates that TPB-DMeTP-COF form layered frameworks with a pore size of 3.36 nm. For TTA-TTB-COF as an example (FIG.1c), the XRD peaks are located at 3.96°, 6.93°, 8.02°, 10.57°, 25.27°, which can be assigned to the (100), (110), (200), (210) and (001) facts. This result indicates that TTATTB-COF form layered frameworks with a pore size of 2.2 nm. Taking TTA-TFB-COF as an example (FIG.1d), the XRD peaks are located at 5.62°, 9.65°, 11.27°, 14.87°, 25.39°, which can be assigned to the (100), (110), (200), (210) and (001) facts. This result indicates that TTATFB-COFs form layered frameworks with a pore size of 1.6 nm. Taking ACOF-1 as an example (FIG.1e), the XRD peaks are located at 6.81°, 11.76°, 13.647°, 18.33°, 26.29°, which can be assigned to the (100), (110), (200), (120) and (001) facts. This result indicates that ACOF-1 form layered frameworks with a pore size of 0.9 nm. Taking Py-TMQPDA-COFs as an example (FIG.1f), the XRD peaks are located at 1.42°, 2.88°, 4.24°, 5.68°, 23.46°, which can be assigned to the (100), (200), (300), (400) and (001) facts. This result indicates that Py-TMQPDA-COFs form layered frameworks with a pore size of 6.0 nm. Taking Py-2,2’-BPyPh-COF as an example (FIG. 1g), the XRD peaks are located at 3.17°, 4.70°, 6.40°, 9.61°, 12.85°, 23.75°,which can be assigned to the (110), (020), (220), (330), (440) and (001) facts. This result indicates that Py-2,2’-BPyPh-COF form layered frameworks with a pore size of 2.58 nm. Taking Py-DMTP-COF as an example (FIG.1h), the XRD peaks are located at 3.71°, 5.64°, 7.50°, 11.30°, 23.34°, which can be assigned to the (110), (020), (220), (330) and (001) facts. This result indicates that Py-DMTP-COF form layered frameworks with a pore size of 1.80 nm. Taking TFBCz-PDA-COFs as an example (FIG.1i), the XRD peaks are located at 4.93°, 6.95°, 9.86°, 14.87°, 22.02°, which can be assigned to the (110), (200), (220), (420) and (001) facts. This result indicates that TFBCz-PDA-COF form layered frameworks with a pore size of 1.50 nm. Taking HFPTP-PDA-COF as an example (FIG.1j), the XRD peaks are located at 4.05°, 6.97°, 8.08°, 24.24°, which can be assigned to the (100), (110), (200) and (001) facts. This result indicates that HFPTP-PDA-COF form layered frameworks with a pore size of 1.1 nm. Taking HFPTP-BPDA-COF as an example (FIG. 1k), the XRD peaks are located at 3.43°, 5.99°, 6.93°, 9.16°, 10.35°, 24.80°, which can be assigned to the (100), (110), (200), (210),(300) and (001) facts. This result indicates that HFPTP-BPDA-COF form layered frameworks with a pore size of 1.55 nm. Taking TPB-TMBPDA-COF as an example, the IR exhibited vibration bands at 1621.84, 1680.66 and 2926.45 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that TPB-TMBPDA-COF was formed by imine linkage between the monomer TPB and TMBPDA. Taking TPB-DMeTP-COF as an example, the IR exhibited vibration bands at 1620.88, 1693.19 and 2915.84 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that TPBDMeTP-COF was formed by imine linkage between the monomer TPB and DMeTP. Taking TTA-TTB-COF as an example, the IR exhibited vibration bands at 1618.75, 1678.35, and 3208.19 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that TTA-TTBCOF was formed by imine linkage between the monomer TTA and TTB. Taking TTA-TFB-COF as an example, the IR exhibited vibration bands at 1630.31, 1703.97 and 3382.44 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that TTA-TFB-COF was formed by imine linkage between the monomer TTA and TFB. Taking ACOF-1 as an example, the IR exhibited vibration bands at 1633.14, 1701.14 and 3424.35 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that ACOF-1 was formed by imine linkage between the monomer hydrazine and TFB. Taking Py-TMQPDA-COF as an example, the IR exhibited vibration bands at 1604.82, 1677.06 and 3373.94 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that Py-TMQPDA-COF was formed by imine linkage between the monomer PyTTA and TMQPDA. Taking Py-2,2’-BPyPh-COF as an example, the IR exhibited vibration bands at 1621.82, 1701.14 and 3451.85 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that Py-2,2’-BPyPh-COF was formed by imine linkage between the monomer PyTTA and 2,2’-BPyPh. Taking Py-DMTP-COF as an example, the IR exhibited vibration bands at 1598.70, 1677.77 and 3363.25 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that Py-DMTPCOF was formed by imine linkage between the monomer PyTTA and DMTP. Taking TFBCz-PDA -COF as an example, the IR exhibited vibration bands at 1618.98, 1694.05 and 3369.69 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that TFBCz-PDA -COF was formed by imine linkage between the monomer TFBCz and PDA. Taking HFPTP-PDA-COF as an example, the IR exhibited vibration bands at 1623.23, 1701.14 and 3366.86 cm -1 , which were assigned to the C=N, C=N, C=O and N-H bonds, respectively. This result indicates that HFPTP-PDA-COF was formed by imine linkage between the monomer HFPTP and PDA. Taking HFPTP-BPDA-COF as an example, the IR exhibited vibration bands at 1621.82, 1698.30 and 3441.93 cm -1 , which were assigned to the C=N, C=O and N-H bonds, respectively. This result indicates that HFPTP-BPDA -COF was formed by imine linkage between the monomer HFPTP and BPDA. All COFs are porous materials and exhibited distinct nitrogen sorption isotherm curves (FIG. 2). Taking TPB-TMBPDA-COF as an example (FIG.2a), the TPB-TMBPDA-COF (BET) surface area ranged from 1500 to 1800 m 2 g -1 , the pore volume ranged from 1.28 to 1.31 cm 3 g -1 , and the pore size was 3.82 nm. Taking TPB-DMeTP-COF as an example (FIG.2b), the TPB-DMeTP-COF (BET) surface area ranged from 2800 to 3000 m 2 g -1 , the pore volume ranged from 1.55 to 1.62 cm 3 g -1 , and the pore size was 3.36 nm. Taking TTA-TTB-COF as an example (FIG.2c), the TTA-TTB-COF (BET) surface area ranged from 1700 to 1800 m 2 g -1 , the pore volume ranged from 0.90 to 1.10 cm 3 g -1 , and the pore size was 2.2 nm. Taking TTA-TFB-COF as an example (FIG.2d), the TTA-TFB-COF (BET) surface area ranged from 1300 to 1500 m 2 g -1 , the pore volume ranged from 0.60 to 0.80 cm 3 g -1 , and the pore size was 1.6 nm. Taking ACOF-1 as an example (FIG.2e), the ACOF-1 (BET) surface area ranged from 900 to 1100 m 2 g -1 , the pore volume ranged from 0.40 to 0.50 cm 3 g -1 , and the pore size was 0.9 nm. Taking Py-TMQPDA-COF as an example (FIG.2f), the Py-TMQPDA-COF (BET) surface area ranged from 1480 to 1560 m 2 g -1 , the pore volume ranged from 1.20 to 1.22 cm 3 g -1 , and the pore sizes were 6.0 and 2.5 nm. Taking Py-2,2’-BPyPh-COF as an example (FIG.2g), the Py-2,2’-BPyPh-COF (BET) surface area ranged from 1600 to 1750 m 2 g -1 , the pore volume ranged from 0.70 to 0.80 cm 3 g -1 , and the pore size was 2.6 nm. Taking Py-DMTP-COF as an example (FIG. 2h), the Py-DMTP-COF (BET) surface area ranged from 1600 to 1700 m 2 g -1 , the pore volume ranged from 1.20 to 1.25 cm 3 g -1 , and the pore size was 1.8 nm. Taking TFBCz-PDA-COF as an example (FIG.2i), the TFBCz-PDA-COF (BET) surface area ranged from 1500 to 1650 m 2 g -1 , the pore volume ranged from 0.60 to 0.80 cm 3 g -1 , and the pore size was 1.5 nm. Taking HFPTP-PDA-COF as an example (FIG. 2j), the HFPTP-PDA (BET) surface area ranged from 510 to 600 m 2 g -1 , the pore volume ranged from 0.32 to 0.40 cm 3 g -1 , and the pore sizes were 1.1 and 1.9 nm. Taking HFPTP-BPDA-COFs-COF as an example (FIG. 2k), the HFPTP-BPDA-COFs (BET) surface area ranged from 900 to 1000 m 2 g -1 , the pore volume ranged from 0.40 to 0.50 cm 3 g -1 , and the pore sizes were 1.2 and 1.5 nm. We unambiguously characterized the chemical structure of these COFs by various analytic methods (FIGS.3-7). FTIR exhibited typical stretching vibration bands at 1622 cm -1 and 1590 cm -1 , which were assigned to the C=N bond of TPB-TMBPDA-COF and TPB-TMQPDA-COF (FIG.8). TGA indicates that these COFs are stable up to 300-500 °C under N 2 atmosphere. Solid-state 13 C CP/MAS NMR shows signals at 153.5 and 150.8 parts per million (ppm), which can be assigned to the carbon atom of C=N unit of TPB-TMBPDA-COF and TPB-TMQPDA- COF, respectively. Example 55. Stability of COFs Stability test The COF samples (100 mg, prepared in the above examples) were dispersed in different solvents, including in 2 ml of boiling water (100 °C), HCl (12 M), NaOH (14 M), and H 3 PO 4 (0.7 M, a THF solution (4 mL) of H 3 PO 4 (270 mg)) solution, and stirred for one week. The COF samples in water were collected and dried at 120 °C under vacuum for 12 h. The COF samples in THF solution of H 3 PO 4 and aqueous HCl solution were washed with a large amount of water, neutralized with triethylamine, rinsed with water and ethanol, and dried under vacuum at 120 °C for 12 h. The COF sample in the aqueous NaOH solution was washed with a large amount of water and THF and dried under vacuum at 120 °C for 12 h. These samples were then subjected to PXRD, infrared spectroscopy and nitrogen-sorption isotherm measurements. Fenton test The COF sample (100 mg) was kept in Fenton’s reagent (40 mL, 3% H 2 O 2 , 3 ppm Fe(II)) for 24 h. The resulting sample was washed with THF, dried under vacuum at 120 °C for 12 h and subjected to PXRD and nitrogen sorption isotherm measurements. Results and discussion To examine chemical stability, we dispersed the TPB-TMBPDA-COF and TPB-TMQPDA-COF samples in THF, water (100 °C), aqueous H 3 PO 4 (0.7 M in THF), aqueous HCl (12 M), and NaOH (14 M) solutions, for one week and observed that all the three new COF are stable enough to retain their crystallinity and porosity (FIG.9). We further investigated the anti-oxidation stability by Fenton test and confirmed that the crystallinity and porosity of TPB-TMBPDA-COF and TPB-TMQPDA-COF did not have a big change (FIG. 9, (ii) curves and (ii) dots). Further, the porosity of TPB-TMBPDA-COF, TPB- TMQPDA-COF treated in different conditions did not have a big change (FIG.10). Taking TPB-DMeTP-COF as an example, TPB-DMeTP-COF retained its crystallinity after treatments with different organic solvents, strong acid (12 M HCl), strong base (14 M NaOH) and boiling water for 7 days (FIG.11). Taking TPB-TMBPDA-COF as an example, TPB-TMBPDA-COF was stable up to 400 °C under nitrogen. Taking TPB-DMeTP-COF as an example, TPB-DMeTP-COF was stable up to 440 °C under nitrogen. Taking TTA-TTB-COF as an example, TTA-TTB-COF was stable up to 500 °C under nitrogen. Taking TTA-TFB-COF as an example, TTA-TFB-COF was stable up to 500 °C under nitrogen. Taking ACOF-1 as an example, ACOF-1 was stable up to 300 °C under nitrogen. Taking Py-TMQPDA-COF as an example, Py-TMQPDA-COF was stable up to 400 °C under nitrogen. Taking Py-2,2’-BPyPh-COF as an example, Py-2,2’-BPyPh-COF was stable up to 400 °C under nitrogen. Taking Py-DMTP-COF as an example, Py-DMTP-COF was stable up to 250 °C under nitrogen. Taking TFBCz-PDA-COF as an example, TFBCz-PDA-COF was stable up to 400 °C under nitrogen. Taking HFPTP-PDA-COFs as an example, HFPTP-PDA-COFs was stable up to 500 °C under nitrogen. Taking HFPTP-BPDA-COFs as an example, HFPTP-BPDA-COFs was stable up to 500 °C under nitrogen. Example 56. Proton transport Proton conductivity measurement Proton conductivity was measured by impedance method on a HIOKI model IM3570 impedance analyser, with a two-probe electrochemical cell with the frequency range 4 Hz to 500 MHz and an input voltage 100 mV. The membranes were connected to electrodes and kept at different temperatures ranging from 80 to 180 °C under dried nitrogen atmosphere. Results and discussion COFs can be loaded with different contents of phosphoric acid to prepare different hybrids and membranes. We filled the channels of these COFs with neat H 3 PO 4 crystal via a vacuum impregnation method (see Examples 27-40) to prepare phosphoric acid-COFs hybrids according to the pore volume of COFs and the density of H 3 PO 4 (1.83 g cm –3 ) and the amount of full loading content of H 3 PO 4 listed in Table 9. The resulting phosphoric acid-COFs hybrids have almost no crystallinity and are nonporous as the channels are fully filled by amorphous H 3 PO 4 (FIGS.3-8). Energy-dispersive X-ray analysis displayed a homogenous distribution of P atoms across the phosphoric acid-COFs hybrids (FIGS.12-17). FTIR spectra demonstrated the hydrogen-bonding interactions between the channel walls and H 3 PO 4 , as evident by the red shift for the vibrational band of C=N bonds (FIGS.3-8). Previous study revealed that the binding energy of hydrogen-bonding interaction between the N and H 3 PO 4 is very high and can form 3D multichain multipoint interactions across the whole channels, which are strong enough to confine and stabilize the H 3 PO 4 network. Table 9. Porosity of COFs and full loading content of phosphoric acid. In the impedance spectra, we observed that with increasing temperature, the resistance decreases. Phosphoric acid-TPB-DMeTP-COFs hybrids at 160 °C yields a curve with an intersection at the x-axis to give a resistance of 0.79 Ω, from which the anhydrous proton conductivity (σ) was calculated to be as high as 3.06 × 10 –1 S cm –1 . This is the highest value reported up to now and is about threefold compared to molten H 3 PO 4 (~1 × 10 –1 S cm –1 ). Further, the proton conductivity is significantly increased by 2–8 orders of magnitude higher than those of other analogues under similar conditions (Table 10). Compared to other typical systems, our COF hybrids exhibited superior proton conductivity (Table 10). The amount of H 3 PO 4 in full filled phosphoric acid-TPB-DMTP-COFs, phosphoric acid-TPB-TMBPDA-COFs, phosphoric acid-TPB-TMQPDA-COFs, phosphoric acid-TTA-TTB-COFs, phosphoric acid- TTA-TFB-COFs and phosphoric acid-ACOF-1 hybrid are listed in Table 9 and the proton conductivity at 160 °C is 5.02 × 10 –2 , 4.29 × 10 –2 , 3.39 × 10 –2 , 2.52 × 10 –2 , 1.12 × 10 –2 , 1.09 × 10 –2 , 1.39 × 10 –3 , 1.97 × 10 –3 , 1.04 × 10 –4 , 6.82 × 10 –5 , 1.67 × 10 –5 S cm –1 , respectively (Table 11). Table 10. Proton conductivity of reported systems.
Table 11. Anhydrous proton conductivities of full loading H3PO4 in different kinds of COFs at different temperatures. The proton conductivity is dependent on temperature and is 9.34 × 10 –2 , 1.08 × 10 –1 , 1.29 × 10 –1 , 1.47 × 10 –1 , 1.88 × 10 –1 , 2.28 × 10 –1 S cm –1 at 100, 110, 120, 130, 140 and 150 °C, respectively, for phosphoric acid-TPB-DMeTP-COFs hybrids (Table 11). These data confirm that the higher pore volume of TPB-DMeTP-COFs enables phosphoric acid-TPB-DMeTP- COFs hybrids to possess larger amount of proton carrier, and large pores enable super proton transport over a wide range of temperatures. Further, the smaller amount of filled H 3 PO 4 in the channels according to the pore volume demonstrated a larger resistance of phosphoric acid- COFs hybrids in the impedance. The proton conductivity for phosphoric acid-TPB-DMTP- COFs is 1.32 × 10 –2 , 1.72 × 10 –2 , 2.12 × 10 –2 , 2.62 × 10 –2 , 3.21 × 10 –2 , 3.97 × 10 –2 S cm –1 at 100, 110, 120, 130, 140 and 150 °C, respectively (Table 11). For phosphoric acid-TPB- TMBPDA-COFs, the value is 1.71 × 10 –2 , 2.05 × 10 –2 , 2.41 × 10 –2 , 2.77 × 10 –2 , 3.17 × 10 –2 , 3.61 × 10 –2 S cm –1 at 100, 110, 120, 130, 140 and 150 °C, respectively (Table 11). The conductivity of phosphoric acid-TTA-TTB-COFs is 1.43 × 10 –3 , 2.15 × 10 –3 , 3.06 × 10 –3 , 4.05 × 10 –3 , 5.38 × 10 –3 , 7.40 × 10 –3 S cm –1 at 100, 110, 120, 130, 140 and 150 °C, respectively (Table 11). For phosphoric acid-TPB-TMQPDA-COFs, the proton conductivity is 2.58 × 10 –4 , 3.48 × 10 –4 , 4.50 × 10 –4 , 5.80 × 10 –4 , 7.48 × 10 –4 , 1.03 × 10 –3 S cm –1 at 100, 110, 120, 130, 140 and 150 °C, respectively (Table 11). The proton conductivity for phosphoric acid-TTA- TFB-COFs is 1.61 × 10 –4 , 2.47 × 10 –4 , 3.76 × 10 –4 , 5.44 × 10 –4 , 8.18 × 10 –4 , 1.27 × 10 –3 S cm – 1 at 100, 110, 120, 130, 140 and 150 °C, respectively (Table 11). For phosphoric acid-ACOF- 1 hybrid, the conductivity is 3.06 × 10 –6 , 5.47 × 10 –6 , 8.62 × 10 –6 , 1.48 × 10 –5 , 2.41 × 10 –5 , 4.32 × 10 –5 S cm –1 at 100, 110, 120, 130, 140 and 150 °C, respectively (Table 11). We also plotted the proton conductivity of each system from 100-160 °C and data measured at 160 °C in order to observe clearly. Py-DMTP-COF (1.23 cm 3 g –1 ) and Py-TMQPDA-COF (1.22 cm 3 g –1 ) have similar pore volume but the proton conductivities of phosphoric acid-Py-DMTP-COF are higher than those of phosphoric acid-Py-TMQPDA-COFs when measured at 140, 150, 160 °C; however, when measured at lower temperatures (100, 110, 120, 130 °C), the proton conductivities of phosphoric acid-Py-TMQPDA-COFs are larger than those of phosphoric acid-Py-DMTP-COF. This result indicates that the larger pores promote the transport of proton carrier at lower temperatures. The pore volume for TTA-TTB-COFs (0.93 cm 3 g –1 ) is higher than that of Py-2,2’-BPyPh-COFs (0.78 cm 3 g –1 ). The conductivity for phosphoric acid-TTA-TTB-COFs (1.12 × 10 –2 S cm –1 ) at 160 °C is similar to that of Py-2,2’-BPyPh-COFs (1.09 × 10 –2 S cm –1 ), and when measured at lower temperatures, the proton conductivity of phosphoric acid-Py-2,2’-BPyPh-COFs is higher than that of phosphoric acid-TTA-TTB-COFs measured under the same temperature. This phenomenon indicates the significant role of the “N” in the framework except the C=N bonds. The “N” in the framework further strengthens the interaction between the 3D H 3 PO 4 network and frameworks within channels. TFBCz-PDA-COFs and TTA-TFB-COFs have the same pore size (1.5 nm) and the pore volume of TFBCz-PDA-COFs (0.68 cm 3 g –1 ) is bigger than that of TTA-TFB-COFs (0.61 cm 3 g –1 ). At 150 and 160 °C, the proton conductivity for phosphoric acid-TFBCz-PDA-COFs is smaller than that of phosphoric acid-TTA-TFB-COFs and below 150 °C, the conductivity became normal and higher pore volume displayed better conductivity for phosphoric acid- TFBCz-PDA-COFs. This result indicates that at a higher temperature (> 150 °C), the hexagonal structural TTA-TFB-COFs are beneficial for proton transport compared to hexagonal TFBCz-PDA-COFs. Proton conduction is a thermal activation process and the conductivity (s) can be described by the Arrhenius equation of s(T) = s 0 e –Ea/RT , where s 0 is the pre-exponential factor, Ea is the activation energy (eV), R is the universal gas constant (= 8.3144 J mol K –1 ) and T is absolute temperature (K). Plotting Logs versus temperature (T –1 ) yield linear curves; from the slopes, the Ea can be calculated. The activation energy for phosphoric acid-TPB-DMeTP-COFs, phosphoric acid-TPB-DMTP- COFs, phosphoric acid-TPB-TMBPDA-COFs, phosphoric acid-Py-DMTP-COFs, phosphoric acid-Py-TMQPDA-COFs, phosphoric acid-TTA-TTB-COFs, phosphoric acid-Py-2,2’-BPyPh- COFs, phosphoric acid-TFBCz-PDA-COFs, phosphoric acid-TTA-TFB-COFs, phosphoric acid-HFPTP-BPDA-COFs, phosphoric acid-ACOF-1 hybrid, phosphoric acid-HFPTP-PDA- COFs hybrids are 0.27, 0.30, 0.20, 0.45, 0.24, 0.46, 0.45, 0.38, 0.57, 0.67, 0.72 and 0.78 eV, respectively. The activation energy for phosphoric acid-TPB-TMBPDA-COFs and phosphoric acid-Py-TMQPDA-COFs are smaller compared to other systems, which indicates a lower- energy hopping over the proton network confined in the nanochannels of large hexagonal mesopores. We further plotted activation energies and normalized the conductivity of these COFs, and we set the conductivity of phosphoric acid-HFPTP-PDA-COFs hybrids as base (set value as one), and found that with increase in pore volume, the conductivity increases dramatically in an exponential mode. The conductivity of phosphoric acid-TPB-DMTP-COFs and phosphoric acid-TPB-DMeTP-COFs are about 716 and 3660 times larger than that of phosphoric acid-HFPTP-PDA-COFs hybrids. When we selected the Ea of the six hexagonal COFs, we surprisingly found that the Ea of the six hexagonal COFs exhibited a linear relationship with pore size (FIG.18). We further investigated different filled ratio of H 3 PO 4 in four different COFs (TPB-DMeTP-COF, Py-2,2’-BPyPh-COF, HFPTP-BPDA-COF and ACOF-1) to disclose the impact on proton conductivity. The loading contents with respect to full loading are 15%, 30%, 50%, 60%, 70%, and 80%. The amount of the four kinds of hybrids with different ratios of full filled is listed in Table 12. The resulting different ratios of phosphoric acid-TPB-DMeTP-COF hybrids, phosphoric acid-Py-2,2’-BPyPh-COF hybrids, phosphoric acid-HFPTP-BPDA-COFs hybrids and phosphoric acid-ACOF-1 hybrids have almost no crystallinity and are nonporous as the pore are occupied by H 3 PO 4 , and FTIR spectra revealed the hydrogen-bonding interaction between the channel walls and H 3 PO 4 , as evident by red shift for the vibrational band of C=N bonds (FIGS. 3, 7 and 8). Phosphoric acid-TPB-DMeTP-COF with 15% loading (43.9 wt%) exhibited proton conductivities of 7.82 × 10 –6 , 1.38 × 10 –5 , 2.29 × 10 –5 , 3.78 × 10 –5 , 6.16 × 10 – 5 , 1.03 × 10 –4 , 1.65 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG. 19a, Table 13). Phosphoric acid-TPB-DMeTP-COF with 30% loading (87.8 wt%) exhibited proton conductivities of 5.30 × 10 –5 , 7.74 × 10 –5 , 1.29 × 10 –4 , 2.05 × 10 –4 , 3.01 × 10 – 4 , 4.46 × 10 –4 , 6.76 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG. 19b, Table 13). Phosphoric acid-TPB-DMeTP-COF with 50% loading (146.4 wt%) exhibited proton conductivities of 1.48 × 10 –4 , 2.22 × 10 –4 , 3.20 × 10 –4 , 4.47 × 10 –4 , 6.29 × 10 – 4 , 8.18 × 10 –4 , 1.19 × 10 –3 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG. 19c, Table 13). Phosphoric acid-TPB-DMeTP-COF with 60% loading (175.7 wt%) exhibited proton conductivities of 1.67 × 10 –3 , 2.39 × 10 –3 , 3.36 × 10 –3 , 4.12 × 10 –3 , 5.39 × 10 – 3 , 6.91 × 10 –3 , 9.08 × 10 –3 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG. 19d, Table 13). Phosphoric acid-TPB-DMeTP-COF with 70% loading (204.9 wt%) exhibited proton conductivities of 2.57 × 10 –3 , 3.78 × 10 –3 , 4.95 × 10 –3 , 7.24 × 10 –3 , 9.71 × 10 – 3 , 1.29 × 10 –2 , 1.31 × 10 –2 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG. 19e, Table 13). Phosphoric acid-TPB-DMeTP-COF with 80% loading (234.2 wt%) exhibited proton conductivities of 7.92 × 10 –2 , 9.49 × 10 –2 , 1.07 × 10 –1 , 1.20 × 10 –1 , 1.35 × 10 – 1 , 1.54 × 10 –1 , 1.75 × 10 –1 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.19f, Table 13). Temperature-dependent proton conductivities revealed that the Ea value is 0.70, 0.60, 0.48, 0.38, 0.40 and 0.18 eV for 15% (43.9 wt%), 30% (87.8 wt%), 50% (146.4 wt%), 60% (175.7 wt%), 70% (204.9 wt%), and 80% (234.2 wt%), respectively. Table 12. COFs with different loading contents with respect to the full loading (100%). Table 13. Anhydrous proton conductivities of H 3 PO 4 loaded into TPB-DMeTP-COF with different ratios at different temperatures. Phosphoric acid-Py-2,2’-BPyPh-COF with 15% loading (21.4 wt%) exhibited proton conductivities of 2.16 × 10 –8 , 3.25 × 10 –8 , 4.78 × 10 –8 , 7.51 × 10 –8 , 1.21 × 10 –7 , 2.04 × 10 –7 , 3.38 × 10 –7 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.20a, Table 14). Phosphoric acid-Py-2,2’-BPyPh-COF with 30% loading (42.8 wt%) exhibited proton conductivities of 7.92 × 10 –7 , 1.44 × 10 –6 , 2.67 × 10 –6 , 4.38 × 10 –6 , 7.97 × 10 –6 , 1.31 × 10 –5 , 2.08 × 10 –5 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.20b, Table 14). Phosphoric acid-Py-2,2’-BPyPh-COF with 50% loading (71.4 wt%) exhibited proton conductivities of 9.07 × 10 –6 , 1.59 × 10 –5 , 2.52 × 10 –5 , 3.97 × 10 –5 , 6.24 × 10 –5 , 1.00 × 10 –4 , 1.63 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.20c, Table 14). Phosphoric acid-Py-2,2’-BPyPh-COF with 60% loading (85.6 wt%) exhibited proton conductivities of 1.64 × 10 –5 , 2.69 × 10 –5 , 4.21 × 10 –5 , 6.73 × 10 –5 , 1.06 × 10 –4 , 1.55 × 10 –4 , 2.03 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.20d, Table 14). Phosphoric acid-Py-2,2’-BPyPh-COF with 70% loading (99.9 wt%) exhibited proton conductivities of 5.60 × 10 –5 , 8.88 × 10 –5 , 1.37 × 10 –4 , 2.06 × 10 –4 , 3.06 × 10 –4 , 4.34 × 10 –4 , 6.10 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.20e, Table 14). Phosphoric acid-Py-2,2’-BPyPh-COF with 80% loading (114.2 wt%) exhibited proton conductivities of 7.20 × 10 –5 , 1.09 × 10 –4 , 1.58 × 10 –4 , 2.29 × 10 –4 , 3.28 × 10 –4 , 4.46 × 10 –4 , 6.79 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.20f, Table 14). Temperature-dependent proton conductivities revealed that the Ea value is 0.64, 0.76, 0.66, 0.60, 0.56 and 0.47 eV for 15% (21.4 wt%), 30% (42.8 wt%), 50% (71.4 wt%), 60% (85.6 wt%), 70% (99.9 wt%), and 80% (114.2 wt%), respectively. Phosphoric acid-HFPTP-BPDA-COFs with 15% loading (13.2 wt%) exhibited proton conductivities of 2.03 × 10 –9 , 4.30 × 10 –9 , 6.99 × 10 –9 , 1.09 × 10 –8 , 1.66 × 10 –8 , 2.68 × 10 –8 , 4.76 × 10 –8 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.21a, Table 15). Phosphoric acid-HFPTP-BPDA-COFs with 30% loading (26.4 wt%) exhibited proton conductivities of 2.10 × 10 –8 , 2.79 × 10 –8 , 3.52 × 10 –8 , 4.38 × 10 –8 , 5.83 × 10 –8 , 7.34 × 10 –8 , 9.80 × 10 –8 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.21b, Table 15). Phosphoric acid-HFPTP-BPDA-COFs with 50% loading (43.9 wt%) exhibited proton conductivities of 3.49 × 10 –8 , 3.60 × 10 –8 , 4.17 × 10 –8 , 5.51 × 10 –8 , 8.55 × 10 –8 , 1.39 × 10 –7 , 2.36 × 10 –7 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.21c, Table 15). Phosphoric acid-HFPTP-BPDA-COFs with 60% loading (52.7 wt%) exhibited proton conductivities of 4.61 × 10 –8 , 6.81 × 10 –8 , 1.22 × 10 –7 , 2.10 × 10 –7 , 3.74 × 10 –7 , 6.39 × 10 –7 , 1.08 × 10 –6 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.21d, Table 15). Phosphoric acid-HFPTP-BPDA-COFs with 70% loading (61.5 wt%) exhibited proton conductivities of 5.47 × 10 –8 , 8.51 × 10 –8 , 1.34 × 10 –7 , 2.21 × 10 –7 , 3.69 × 10 –7 , 6.66 × 10 –7 , 1.28 × 10 –6 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.21e, Table 15). Phosphoric acid-HFPTP-BPDA-COFs with 80% loading (70.3 wt%) exhibited proton conductivities of 7.02 × 10 –8 , 1.13 × 10 –7 , 2.04 × 10 –7 , 3.48 × 10 –7 , 6.01 × 10 –7 , 1.07 × 10 –6 , 1.92 × 10 –6 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.21f, Table 15). Temperature-dependent proton conductivities revealed that the Ea value is 0.70, 0.35, 0.45, 0.75, 0.72 and 0.77 eV for 15% (13.2 wt%), 30% (26.4 wt%), 50% (43.9 wt%), 60% (52.7 wt%), 70% (61.5 wt%), and 80% (70.3 wt%), respectively. Table 14. Anhydrous proton conductivities of H 3 PO 4 loaded into Py-2,2’-BPyPh-COF with different ratios at different temperatures. Table 15. Anhydrous proton conductivities of H 3 PO 4 loaded into HFPTP-BPDA-COF with different ratios at different temperatures. Phosphoric acid-ACOF-1 with 15% loading (11.3 wt%) exhibited proton conductivities of 1.43 × 10 –9 , 1.92 × 10 –9 , 2.65 × 10 –9 , 3.43 × 10 –9 , 4.42 × 10 –9 , 5.64 × 10 –9 , 7.18 × 10 –9 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.22a, Table 16). Phosphoric acid- ACOF-1 with 30% loading (22.5 wt%) exhibited proton conductivities of 1.20 × 10 –8 , 1.54 × 10 –8 , 2.04 × 10 –8 , 2.84 × 10 –8 , 4.08 × 10 –8 , 6.65 × 10 –8 , 9.55 × 10 –8 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.22b, Table 16). Phosphoric acid-ACOF-1 with 50% loading (37.5 wt%) exhibits proton conductivities of 1.46 × 10 –7 , 2.22 × 10 –7 , 3.35 × 10 –7 , 5.24 × 10 –7 , 7.93 × 10 –7 , 1.22 × 10 –6 , 1.85 × 10 –6 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG. 22c, Table 16). Phosphoric acid-ACOF-1 with 60% loading (45.0 wt%) exhibited proton conductivities of 1.85 × 10 –7 , 2.94 × 10 –7 , 4.66 × 10 –7 , 7.21 × 10 –7 , 1.14 × 10 –6 , 1.76 × 10 –6 , 2.65 × 10 –6 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.22d, Table 16). Phosphoric acid-ACOF-1 with 70% loading (52.5 wt%) exhibited proton conductivities of 2.21 × 10 –7 , 3.70 × 10 –7 , 6.20 × 10 –7 , 9.76 × 10 –7 , 1.51 × 10 –6 , 2.29 × 10 –6 , 3.41 × 10 –6 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.22e, Table 16). Phosphoric acid-ACOF-1 with 80% loading (60.0 wt%) exhibited proton conductivities of 2.77 × 10 –6 , 4.07 × 10 –6 , 6.16 × 10 –6 , 8.90 × 10 –6 , 1.29 × 10 –5 , 1.84 × 10 –5 , 2.54 × 10 –5 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.22f, Table 16). Temperature- dependent proton conductivities revealed that the Ea value is 0.37, 0.49, 0.59, 0.62, 0.66 and 0.52 eV for 15% (11.3 wt%), 30% (22.5 wt%), 50% (37.5 wt%), 60% (45.0 wt%), 70% (52.5 wt%), and 80% (60.0 wt%) respectively. Table 16. Anhydrous proton conductivities of H 3 PO 4 loaded into ACOF-1 with different ratios at different temperatures. In order to clearly observe the trend of conductivity in four COFs with different ratios, we plotted the proton conductivity data in FIG.23. After normalizing the conductivity of different ratios of the four COFs, we observed that conductivities from 15% to 70% of full filled proton carriers did not have a great change. For phosphoric acid-TPB-DMeTP-COF hybrids, the conductivity of full filled is 1856 times larger than 15% full filled, and the Ea exhibited a decreasing tendency with increase in the ratio of full filled amount. For phosphoric acid-Py-2,2’-BPyPh-COF hybrids, phosphoric acid-HFPTP-BPDA-COFs hybrids, phosphoric acid-ACOF-1 hybrids, the conductivity of full filled are 32340, 2180, and 9498 times larger than 15% full filled, respectively. The dramatic difference in conductivity originates from the fact that the C=N sites on the channel walls are dense along the z direction so that a continuous H 3 PO 4 network can still form proximate to the C=N chains even at a low loading content, which offers the pathways for proton transport and the significance role of the functional N group in the frameworks. The activation energies are also different from the phosphoric acid-TPB-DMeTP-COF system. The Ea of phosphoric acid-Py-2,2’-BPyPh-COF hybrids showed a slight increase from 15% to 30% and a decrease trend from 30% to 100% fill, while the activation energies of phosphoric acid- HFPTP-BPDA-COFs hybrids and phosphoric acid-ACOF-1 hybrids displayed a wide fluctuation and increasing drift. We also investigated half of full filled H 3 PO 4 in three different COFs (TPB-DMTP-COF, TTA- TTB-COF and Py-TMQPDA-COF) to disclose the impact of on proton conductivity. The resulting half of full filled phosphoric acid-TPB-DMTP-COF hybrids, phosphoric acid-TTA- TTB-COF hybrids and phosphoric acid- Py-TMQPDA-COF hybrids have almost no crystallinity and are nonporous as the pore are occupied by H 3 PO 4 , and FTIR spectra revealed the hydrogen-bonding interaction between the channel walls and H 3 PO 4 , as evident by red shift for the vibrational band of C=N bonds (FIGS.4, 5 and 10). Phosphoric acid-TPB-DMTP-COF with 50% loading (122.6 wt%) exhibited proton conductivities of 1.25 × 10 –4 , 1.85 × 10 –4 , 2.67 × 10 –4 , 3.77 × 10 –4 , 5.27 × 10 –4 , 7.20 × 10 –4 , 9.99 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.24a, Table 17). Phosphoric acid-TTA-TTB-COF with 50% loading (85.1 wt%) exhibited proton conductivities of 9.72 × 10 –6 , 1.57 × 10 –5 , 2.66 × 10 –5 , 3.94 × 10 –5 , 6.44 × 10 –5 , 1.11 × 10 –4 , 2.00 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG. 24b, Table 17). Phosphoric acid-Py-TMQPDA-COF with 50% loading (111.7 wt%) exhibited proton conductivities of 9.96 × 10 –5 , 1.46 × 10 –4 , 1.98 × 10 –4 , 2.75 × 10 – 4 , 3.97 × 10 –5 , 5.07 × 10 –4 , 7.12 × 10 –4 S cm –1 at 100, 110, 120, 130, 140, 150 and 160 °C, respectively (FIG.24c, Table 17). The conductivity of half ratio of full loading in three hybrids is two order of magnitudes compared with full filling. The activation energy of half of full filling of phosphoric acid-TPB-DMTP-COF, phosphoric acid-TTA-TTB-COF and phosphoric acid-Py- TMQPDA-COF are 0.48, 0.68 and 0.45 eV, respectively (FIG.24d, Table 17). Table 17. Anhydrous proton conductivities of half of full loading H 3 PO 4 in 3 COFs at different temperatures. The conductivity of phosphoric acid-HFPTP-PDA-COFs hybrid membranes is depicted in FIG. 25. a) Conductivity of phosphoric acid-HFPTP-PDA-COFs hybrid membranes In FIG.25 No.1, the conductivity is 4.01 ×10 –7 , 7.88 ×10 –7 , 1.46 ×10 –6 , 2.68 ×10 –6 , 5.01 ×10 – 6 , 8.87 ×10 –6 , 1.67 ×10 –5 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. b) Conductivity of phosphoric acid-ACOF-1 hybrid membranes In FIG.25 No.2, the conductivity is 3.06 ×10 –6 , 5.47 ×10 –6 , 8.62 ×10 –6 , 1.48 ×10 –5 , 2.41 ×10 – 5 , 4.32 ×10 –5 , 6.82 ×10 –5 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. c) Conductivity of phosphoric acid-HFPTP-BPDA-COFs hybrid membranes In FIG.25 No.3, the conductivity is 5.76 ×10 –6 , 9.70 ×10 –6 , 1.66 ×10 –5 , 2.76 ×10 –5 , 4.37 ×10 – 5 , 6.81 ×10 –5 , 1.04 ×10 –4 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. d) Conductivity of phosphoric acid-TTA-TFB-COFs hybrid membranes In FIG.25 No.4, the conductivity is 1.61 ×10 –4 , 2.47 ×10 –4 , 3.76 ×10 –4 , 5.44 ×10 –4 , 8.18 ×10 – 4 , 1.27 ×10 –3 , 1.97 ×10 –3 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. e) Conductivity of phosphoric acid-TFBCz-PDA-COFs hybrid membranes In FIG.25 No.5, the conductivity is 2.58 ×10 –4 , 3.48 ×10 –4 , 4.50 ×10 –4 , 5.80 ×10 –4 , 7.48 ×10 – 4 , 1.03 ×10 –3 , 1.39 ×10 –3 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. f) Conductivity of phosphoric acid-Py-2,2’-BPyPh-COFs hybrid membranes In FIG.25 No.6, the conductivity is 1.55 ×10 –3 , 2.21 ×10 –3 , 3.20 ×10 –3 , 4.41 ×10 –3 , 5.94 ×10 – 3 , 8.03 ×10 –3 , 1.09 ×10 –2 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. g) Conductivity of phosphoric acid-TTA-TTB-COFs hybrid membranes In FIG.25 No.7, the conductivity is 1.43 ×10 –3 , 2.15 ×10 –3 , 3.06 ×10 –3 , 4.05 ×10 –3 , 5.38 ×10 – 3 , 7.40 ×10 –3 , 1.12 ×10 –2 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. h) Conductivity of phosphoric acid-Py-TMQPDA-COFs hybrid membranes In FIG.25 No.8, the conductivity is 9.01 ×10 –3 , 1.07 ×10 –2 , 1.28 ×10 –2 , 1.50 ×10 –2 , 1.78 ×10 – 2 , 2.10 ×10 –2 , 2.52 ×10 –2 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. i) Conductivity of phosphoric acid-Py-DMTP-COFs hybrid membranes In FIG.25 No.9, the conductivity is 4.47 ×10 –3 , 6.89 ×10 –3 , 8.84 ×10 –3 , 1.29 ×10 –2 , 1.69 ×10 – 2 , 2.26 ×10 –2 , 3.39 ×10 –2 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. j) Conductivity of phosphoric acid-TPB-TMBPDA-COFs hybrid membranes In FIG.25 No.10, the conductivity is 1.71 ×10 –2 , 2.05 ×10 –2 , 2.41 ×10 –2 , 2.77 ×10 –2 , 3.17 ×10 – 2 , 3.61 ×10 –2 , 4.29 ×10 –2 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. k) Conductivity of phosphoric acid-TPB-DMTP-COFs hybrid membranes In FIG.25 No.11, the conductivity is 1.32 ×10 –2 , 1.72 ×10 –2 , 2.12 ×10 –2 , 2.62 ×10 –2 , 3.21 ×10 – 2 , 3.96 ×10 –2 , 5.02 ×10 –2 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. l) Conductivity of phosphoric acid-TPB-DMeTP-COFs hybrid membranes In FIG.25 No.12, the conductivity is 9.34 ×10 –2 , 1.08 ×10 –1 , 1.30 ×10 –1 , 1.47 ×10 –1 , 1.88 ×10 – 1 , 2.28 ×10 –1 , 3.06 ×10 –1 S cm –1 at 100, 110, 120, 130, 140, 150, 160 °C. The proton conductivity of phosphoric acid-TPB-DMeTP-COF hybrid membranes with different loading amounts of phosphoric acid is depicted in FIG.26. The proton conductivity of phosphoric acid-COF hybrid membranes of different COF topologies under full loading of phosphoric acid is depicted in FIG.27. The proton conductivity of phosphoric acid-COF hybrid membranes of different COF topology and different phosphoric acid content is depicted in FIG. 28. Here, we report the effect of different pore size (micropores to mesopores) in imine-bonded (C=N) COFs on proton conduction. Dense and aligned nitrogen sites on pore walls in the channels confined and stabilized the H 3 PO 4 network via hydrogen-bonding interactions. The results demonstrate that a higher pore volume attributed to higher conductivity due to the complete 3D hydrogen-bonding network. The relationship between the conductivities and pore volume is not simply increasing of pore volume but provides an unprecedented non-linear increasing diagram after normalization. For hexagon COFs, pore size and activation energy have a linear relationship; larger pore size is beneficial for proton transport. Example 57. 1 H and 31 P NMR analysis We carried out 1 H and 31 P NMR analysis of different ratios (from 15% to 100%) of phosphoric acid-TPB-DMeTP-COF hybrids to investigate the proton conductivity. 1 H NMR one-pulse experiments The 1 H (ν 0 [ 1 H] = 600.18 MHz) NMR one-pulse experiments were acquired with a π/2 pulse of 2.75 μs (determined on adamantane (s) ) and a recycle delay of 10 s. The 31 P (ν 0 [ 31 P] = 242.96 MHz) NMR decoupled one-pulse experiments were acquired with a π/2 pulse of 2.8 μs (determined on (NH 4 )H 2 PO 4(s) ), high power proton decoupling and a recycle delay of 2.5 s. The 31 P and 1 H spin-lattice relaxation times were determined via saturation recovery experiments utilizing 200 and 300 pulse saturation pulse trains, respectively. Results and discussion 31 P NMR of the H 3 PO 4 -loaded COF samples all presented two resonances: the dominant resonance at ~ 0 and ~ -10 ppm can be assigned to H 3 PO 4 . (FIG.29, Table 18). The relative integral of the smaller resonance varies from 2–9 % (which is proportional to the ratio of the 31 P nuclei present in each environment), with the highest percentage given by the 100% H 3 PO 4 sample. The H 3 PO 4 resonance changes in width, where narrower resonances could imply a more solution-like environment (i.e. more mobile), although no trend was observed. 1 H NMR of untreated COF presented 3 resonances: the benzyl hydrogens centred at 6.7 ppm, the methyl hydrogens centered at ~ 3.5 ppm, and water at 4.8 ppm. The water is presumably located within the COF channels. Upon treatment with phosphoric acid, the water in the channels is removed and replaced with H 3 PO 4 , giving the dominant resonance at ~9.4 ppm. The relative integral of the H 3 PO 4 resonance increases with increasing initial H 3 PO 4 content as expected, except for the 15% sample which has an unexpectedly high H 3 PO 4 site occupancy (FIG. 29, Table 18). The varying position of the H 3 PO 4 resonance could imply differences in hydrogen bonding, with higher frequencies representing shorter hydrogen bond lengths; however, no trend was observed. Higher bond lengths could also be explained by the more acidic environments; however, there does not appear to be any correlation with H 3 PO 4 concentration. 1 H variable temperature relaxation measurements was also investigated (FIG. 30). Table 18. 1 H NMR spectra deconvolution parameters and assignments. Therefore, we have developed herein 12 imine-bonded (C=N) COFs with different geometries (hexagon, tetragon, trigon and kagome) and tunable pore size (micropores to mesopores) for designing proton-conducting materials based on stable COFs by exploring their well-defined 1D channels to confine proton network. The structures in FIG.31 illustrate different COFs of various geometries (hexagonal, tetragonal, trigonal and kagome structures), pore size and functional groups. The pore size ranges from microporous (< 2 nm) to mesoporous (> 2 nm). The functional groups on pore walls can be varied with –OH, –OMe, –Me,–F, –Br, – (OCH 2 ) x OCH 3 , etc. The functional groups can be designed to be interactive with a proton carrier (e.g. phosphoric acid) and to stabilize and immobilize the proton carrier network in the nano channels of COFs. Further, the amount of the proton carrier in the membrane can be exactly controlled. We unexpectedly found that the pore volume and filled ratio of proton carriers have a significant influence on proton conductivity. The pore volume plays a vital role in determining the final conductivity of hybrids ascribe to the integrity 3D hydrogen-bonding network. The relationship between the conductivities and pore volume is not simply increasing of pore volume but provides an unprecedented non-linear increasing diagram after normalization; with increasing pore volume, the proton conductivity enhances in an exponential mode. The conductivity of phosphoric acid-TPB-DMeTP-COFs (highest pore volume COFs) is 3660 times larger than the phosphoric acid-HFPTP-BPDA-COFs (smallest pore volume COFs). For hexagonal COFs, pore size and activation energy have a linear relationship, which means in larger pores, the proton carriers undergo a lower energy gap to transport, and so larger pore size is beneficial for proton transport. After normalization of the different ratios of full filled COFs, we found that at lower percentage ratios (15%-70%), the conductivity did not have a big change. However, from 80% to 100% of full filled, the conductivity increased dramatically in an exponential mode and are 1856, 32340, 2180 and 9498 times larger than 15% of full filled of phosphoric acid-TPB-DMeTP-COFs, phosphoric acid- Py-2,2’-BPyPh-COF, phosphoric acid-HFPTP-BPDA-COFs and phosphoric acid- ACOF-1, respectively. Our results suggest that proton transport is correlated with the integrity of the H 3 PO 4 network in the nanochannels; the full filling fabricated a continuous proton network. Table 19. Advantages of the present disclosure. Example 58. Regeneration of COFs Removing phosphoric acid from the phosphoric acid-COFs hybrids regenerates COF materials. The phosphoric acid-COFs hybrid was dispersed in water and stirred for 30 min, and triethylamine was added to the system and the reaction mixture was kept to stir for 30 min. Repeating this process 3-4 times to completely remove phosphoric acid regenerates COF materials for direct use. Example 59. Regeneration of phosphoric acid-COF hybrids Neat H 3 PO 4 was impregnated into regenerated COFs via vacuum assisted method as shown in the above examples. Neat phosphoric acid of different amounts was dissolved in anhydrous THF to form a homogeneous solution. The solution was added to the regenerated COFs solid and the resulting mixture was stirred at room temperature for 3 h. The mixture was heated at 70 °C and evaporated under vacuum to remove THF over a period of 6 h, and kept at 70 °C for 12 h. The resulting powder was collected to yield regenerated phosphoric acid-COF hybrids quantitatively, which were kept under dry inert atmosphere. Example 60. Recycled use The prepared phosphoric acid-COF hybrid membranes with good mechanical properties can be recycled for many times. Example 61. Integration into fuel cells The high proton conductivity of phosphoric acid-COF hybrids can be comparable to the commercial available Naifon materials, making it a promising candidate as solid-state electrolytes in proton exchange membrane fuel cells (PEMFCs). The high proton conductivity of phosphoric acid-COF hybrids can be mounted directly to PEMFCs. The as-prepared self- standing membrane was used as solid-state electrolytes for the construction of PEM fuel cells under H 2 /O 2 operated conditions. The anode and cathode layers were fabricated using a commercial 40% Pt/C catalyst, and on the each electrode, Pt loading was kept as 1 mg cm –1 . Comparative Example 1 The present disclosure demonstrates the highest proton conductivity among four reference patents (CN110982085A, CN113912845A, WO2021041788A1 and CN109593201B) (see Table 20). All the COFs in CN110982085A, CN113912845A, and CN109593201B possess high density of functional groups (azo, SO 3 H- and polyibenzimidazole) except the linkages; all the groups can have strong interaction with the proton carriers, which greatly enhances the proton conduction performance. In contrast, the present disclosure only contain imine groups, which can stabilize the phosphoric acid network. The present disclosure mainly targets the imine bond linkage of COFs. WO2021041788A1 utilises atomic layer of graphene and h-BN as the 2D conducting material, which is quite different from our bulk COF systems.
Table 20. Comparison of the present disclosure with CN110982085A, CN113912845A, WO2021041788A1 and CN109593201 B.
Comparative Example 2 Typical membranes are based on polybenzimidazoles. The difference between typical membranes and the present disclosure is the use of polybenzimidazole as the polymer membrane and the use of an aqueous solution of phosphoric acid as the proton carrier. The present disclosure uses COFs to load pure phosphoric acid in the pores, thus the presently diclosed COFs have a high content of proton carrier and high conductivity. Further, the presently disclosed COF systems work at 100-180 °C, while polybenzimidazole systems work at a temperature lower than 100 °C. Therefore, the COFs disclosed herein exhibited crystallinity, porosity, and excellent thermal stability. These COFs not only retained crystallinity and porosity after treatment in different organic solvents and under harsh conditions (HCl, NaOH, H 3 PO 4 , and boiling water) but also kept stable at 300 to 500°C under nitrogen atmosphere. The prepared phosphoric acid-COF hybrid membranes exhibited good mechanical strength. The membranes exhibited excellent conductivity and kept their conductivity after cycle use. After removing the phosphoric acid from the cycled COFs hybrids, the COFs retained their crystallinity, porosity and thermal stability, and the COFs can be reused and exhibited stable performance in proton conduction. In addition, the present disclosure has high scalability as the monomers are commercially available and the synthesis of COFs is quick and can be scaled to gram and kilogram scales. Finally, the present disclosure has high applicability in fuel cells.