CATALYST AND METHOD FOR PRODUCING ETHYLENE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application claims the benefit of U.S. Provisional Application No. 62/810,007 filed February 25, 2019, which is incorporated herein by reference in its entirety.

FEDERALLY SPONSORED RESEARCH

[0002] This invention was made with government support under DOE-NETL DE FE0029570 awarded by U.S. Department of Energy. The government has certain rights in the invention.

FIELD OF THE INVENTIONS

[0003] The catalysts, compositions, articles, and methods disclosed herein relates to the production of ethylene.

BACKGROUND

[0004] Ethylene, due to its wide range usage in the manufacture of a number of different types of products (e.g., plastics, polymer, fibers, packaging materials, etc.), is the most commercially produced organic chemical in the world with a present global capacity of 334 billion pounds and the expectation to rise between 400 and 450 billion pounds within the next number of years.

[0005] Historically, alkenes or olefins such as ethylene have been produced from petroleum feedstock through naphtha cracking. However, the naphtha cracking process requires a significant amount of energy and capital cost to yield the desired olefins. Due to the increased availability of natural gas (and thus ethane) in the United States, ethane has been increasingly used as feedstock for ethylene production. Conventional steam cracking plants accept ethane or naphtha as feed which are preheated and mixed with steam at very high temperatures (e.g., about 750-900 °C.) in tubular reactors. Thus they are converted to low relative molecular mass alkenes. With ethane as feedstock in steam cracking ethylene is produced.

[0006] Accordingly, it would be desirable to provide a catalyst and production process for ethylene that utilizes ethane and is further more energy efficient in relation to conventional olefin production processes. Described herein are catalysts and methods that converts ethane and CO2 to ethylene. SUMMARY OF THE INVENTION

[0007] Disclosed herein is a catalyst composition comprising the formula:

M1M2M3M4Q - X

wherein Ml is chromium oxide,

wherein M2 is iron oxide,

wherein M3 is cerium oxide,

wherein M4 is zirconia,

wherein Q is tin oxide or nickel oxide, or a combination thereof, and wherein X is sulfate or phosphate.

[0008] Also disclosed herein is a method of producing ethylene comprising the step of: a) reacting ethane with a gas comprising CO2 in the presence of a catalyst composition disclosed herein, thereby producing ethylene.

[0009] Additional advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the aspects described below. The advantages described below will be realized and attained by means of the chemical compositions, methods, and combinations thereof particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.

DESCRIPTION OF THE FIGURES

[0010] The accompanying figures, which are incorporated in and constitute a part of this specification, illustrate several aspects and together with the description serve to explain the principles of the invention.

[0011] FIG. 1 shows long term stability test data under direct flue gas testing of an exemplary non-limiting catalyst composition disclosed herein.

[0012] FIG. 2 shows long term stability test data under captured CO2 testing of an exemplary non-limiting catalyst composition disclosed herein.

[0013] FIG. 3 shows the effect of H2O in reactant feed under direct flue gas testing of an exemplary non-limiting catalyst composition disclosed herein. [0014] FIG. 4A and 4B shows normalized (4A) CO2 conversion and (4B) ethylene yield with respect to O2.CO2 ratio in direct flue gas feed reactant of an exemplary non-limiting catalyst composition disclosed herein.

DETAILED DESCRIPTION

[0015] The disclosed methods and articles can be understood more readily by reference to the following detailed description.

[0016] Before the present compounds, compositions, articles, systems, devices, and/or methods are disclosed and described, it is to be understood that they are not limited to specific articles or methods unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, example methods and materials are now described.

[0017] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.

1. Definitions

[0018] As used herein, nomenclature for compounds, including organic compounds, can be given using common names, IUPAC, IUBMB, or CAS recommendations for nomenclature. When one or more stereochemical features are present, Cahn-Ingold-Prelog rules for stereochemistry can be employed to designate stereochemical priority, E/Z specification, and the like. One of skill in the art can readily ascertain the structure of a compound if given a name, either by systemic reduction of the compound structure using naming conventions, or by commercially available software, such as CHEMDRAWTM (Cambridgesoft Corporation, U.S.A.).

[0019] In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings: [0020] It must be noted that, as used in the specification and the appended claims, the singular forms“a,”“an” and“the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to“a therapeutic agent” includes mixtures of therapeutic agents, reference to“a pharmaceutical carrier” includes mixtures of two or more such carriers, and the like]

[0021]“Optional” or“optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not. For example, the phrase“optionally comprising an adhesive material” means that the adhesive material can or cannot be present and that the description includes both situations.

[0022] Ranges can be expressed herein as from“about” one particular value, and/or to“about” another particular value. When such a range is expressed, a further aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms a further aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as“about” that particular value in addition to the value itself. For example, if the value“10” is disclosed, then“about 10” is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0023] A weight percent (wt. %) of a component, unless specifically stated to the contrary, is based on the total weight of the therapeutic composition or composition or material, in which the component is included.

[0024] References in the specification and concluding claims to parts by weight, of a particular element or component in a composition or article, denote the weight relationship between the element or component and any other elements or components in the composition or article for which a part by weight is expressed. Thus, in a composition containing 2 parts by weight of component X and 5 parts by weight component Y, X and Y are present at a weight ratio of 2:5, and are present in such ratio regardless of whether additional components are contained in the composition.

[0025] Disclosed are the components to be used to prepare the compositions of the invention as well as the compositions themselves to be used within the methods disclosed herein. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds cannot be explicitly disclosed, each is specifically contemplated and described herein. For example, if a particular compound is disclosed and discussed and a number of modifications that can be made to a number of molecules including the compounds are discussed, specifically contemplated is each and every combination and permutation of the compound and the modifications that are possible unless specifically indicated to the contrary. Thus, if a class of molecules A, B, and C are disclosed as well as a class of molecules D, E, and F and an example of a combination molecule, A-D is disclosed, then even if each is not individually recited each is individually and collectively contemplated meaning combinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considered disclosed. Likewise, any subset or combination of these is also disclosed. Thus, for example, the sub-group of A-E, B-F, and C-E would be considered disclosed. This concept applies to all aspects of this application including, but not limited to, steps in methods of making and using the compositions of the invention. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the methods of the invention.

[0026] It is understood that the compositions disclosed herein have certain functions.

Disclosed herein are certain structural requirements for performing the disclosed functions, and it is understood that there are a variety of structures that can perform the same function that are related to the disclosed structures, and that these structures will typically achieve the same result.

2. Catalyst Composition for Producing Ethylene

[0027] Disclosed herein is a catalyst for producing ethylene from ethane and CO2. The CO2 can come a variety of sources, including high purity CO2 sources or lower purity CO2 sources, for example flue gas, such as coal fired flue gas. The catalyst composition disclosed herein drives an ethane oxidative dehydrogenation (ODH) reaction that yields ethylene by using CO2 as a soft oxidant. The overall reaction for producing ethylene is as follows:

C2H6 + CO2 C2H4 + CO + H2O (Eq. 1)

[0028] The desired product (ethylene) of this reaction constitute all the components shown in equation 1. In addition to equation 1, smaller amounts of methane (see equation 2) and hydrogen (see equation 3) are also produced. C H ₆ + 2CO2 CH ₄ + 3CO + H ₂ 0 (Eq. 2)

C ₂ H ₆ + 2C0 ₂ 4 CO + 3 H ₂ (Eq. 3)

[0029] The catalyst disclosed herein have a desired yield of ethylene production. The ethylene yield is determined by multiplying the ethane conversion rate with the selectivity for the production of only ethylene.

[0030] The catalyst disclosed herein is more stable as compared to conventional catalysts used in ODH reactions. Accordingly, the catalyst is more stable when subjected to a flue gas, which contains impurities, such as S0 ₂ , H ₂ 0, and NO, aside from C0 ₂ , as compared to conventional catalysts used in ODH reactions. Thus, an advantage of the ODH reaction process is that carbon dioxide for use as the soft oxidant can be obtained from the flue gas resulting from the burning of a fossil fuel. In particular, the flue gas derived from a fossil fuel power station that bums coal, natural gas or petroleum to generate electricity can be used as a source of C0 ₂ . For example, the flue gas can be derived from a coal fired power plant and be used as the C0 ₂ source. The C0 ₂ that is generated from the coal or other fossil fuel burning processes and that is typically released as flue gas emissions can be instead used in the ODH reaction process (after optional removal of SOx, NOx, etc. from the flue gas), thus reducing the greenhouse gas (GHG) emissions from the fossil fuel burning process.

[0031] Accordingly, disclosed herein is a catalyst composition comprising the formula:

M1M2M3M4Q - X

wherein Ml is chromium oxide,

wherein M2 is iron oxide,

wherein M3 is cerium oxide,

wherein M4 is zirconia,

wherein Q is tin oxide or nickel oxide, or a combination thereof, and wherein X is sulfate or phosphate.

[0032] It is understood that Ml can include all forms of oxides of chromium (Cr), such as Cr (III) and Cr (VI). For example, Ml can comprise Cr ₂ 03. In another example, Ml can comprise CrCh. In yet another example, Ml can comprise Cr ₂ C>3 and CrCh.

[0033] In one aspect, Ml is present in an amount from about 0.1 weight % to about 30 weight % based on the total weight of the catalyst composition. For example, Ml can be present in an amount from about 3 weight % to about 30 weight % based on the total weight of the catalyst composition. In another example, Ml can be present in an amount from about 5 weight % to about 30 weight % based on the total weight of the catalyst composition. In yet another example, Ml can be present in an amount from about 10 weight % to about 30 weight % based on the total weight of the catalyst composition. In yet another example, Ml can be present in an amount from about 0.1 weight % to about 25 weight % based on the total weight of the catalyst composition. In yet another example, Ml can be present in an amount from about 0.1 weight % to about 20 weight % based on the total weight of the catalyst composition. In yet another example, Ml can be present in an amount from about 0.1 weight % to about 15 weight % based on the total weight of the catalyst composition. In yet another example, Ml can be present in an amount from about 5 weight % to about 15 weight % based on the total weight of the catalyst composition.

[0034] It is understood that M2 can include all forms of oxides of iron (Fe), such as Fe (II) and Fe (III). For example, M2 can comprise Fe ₂ C> ₃ . In another example, M2 can comprise Fe ₃ C> ₄ .

In yet another example, M2 can comprise Fe ₂ C> ₃ and Fe ₃ C> ₄ .

[0035] In one aspect, M2 is present in an amount from about 0.1 weight % to about 30 weight % based on the total weight of the catalyst composition. For example, M2 can be present in an amount from about 0.3 weight % to about 20 weight % based on the total weight of the catalyst composition. In another example, M2 can be present in an amount from about 0.5 weight % to about 20 weight % based on the total weight of the catalyst composition. In yet another example, M2 can be present in an amount from about 0.1 weight % to about 20 weight % based on the total weight of the catalyst composition. In yet another example, M2 can be present in an amount from about 0.1 weight % to about 15 weight % based on the total weight of the catalyst composition. In yet another example, M2 can be present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition. In yet another example, M2 can be present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition. In yet another example, M2 can be present in an amount from about 0.5 weight % to about 5 weight % based on the total weight of the catalyst composition.

[0036] It is understood that M3 can include all forms of oxides of cerium (Ce), such as Ce (III) and Ce (IV). For example, M3 can comprise CeCh. In another example, M3 can comprise Ce ₂ C> ₃ . In yet another example, M3 can comprise CeC and Ce ₂ C> ₃ . [0037] In one aspect, M3 is present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition. For example, M3 can be present in an amount from about 0.3 weight % to about 10 weight % based on the total weight of the catalyst composition. In another example, M3 can be present in an amount from about 0.5 weight % to about 10 weight % based on the total weight of the catalyst composition. In yet another example, M3 can be present in an amount from about 2 weight % to about 10 weight % based on the total weight of the catalyst composition. In yet another example, M3 can be present in an amount from about 0.1 weight % to about 8 weight % based on the total weight of the catalyst composition. In yet another example, M3 can be present in an amount from about 0.1 weight % to about 6 weight % based on the total weight of the catalyst composition. In yet another example, M3 can be present in an amount from about 0.5 weight % to about 8 weight % based on the total weight of the catalyst composition. In yet another example, M3 can be present in an amount from about 3 weight % to about 7 weight % based on the total weight of the catalyst composition.

[0038] It is understood that the zirconia representing M4 is used as a support in the catalyst composition. It is commonly known that zirconia has the chemical structure ZrC .

[0039] In one aspect, the amount of M4 is the balance weight % of the catalyst composition based on the amounts of Ml, M2, M3, Q, and X.

[0040] In one aspect, the catalyst composition comprises tin oxide. Thus, in one aspect, Q is tin oxide. It is understood that Q can include all forms of oxides of tin (Sn), such as Sn (II) and Sn (IV). For example, Q can comprise SnO. In another example, Q can comprise SnC . In yet another example, Q can comprise SnO and Sn0 ₂ . In this aspect, tin oxide can be present in an amount from about 0.2 weight % to about 20 weight % based on the total weight of the catalyst composition. For example, tin oxide can be present in an amount from about 0.2 weight % to about 10 weight % based on the total weight of the catalyst composition. In another example, tin oxide can be present in an amount from about 0.2 weight % to about 5 weight % based on the total weight of the catalyst composition. In another example, tin oxide can be present in an amount from about 0.2 weight % to about 3 weight % based on the total weight of the catalyst composition.

[0041] In one aspect, the catalyst composition comprises nickel oxide. Thus, in one aspect, Q is nickel oxide. It is understood that Q can include all forms of oxides of nickel (Ni), such as Ni (II) and Ni (III). For example, Q can comprise NiO. In this aspect, nickel oxide can be present in an amount from about 0.2 weight % to about 20 weight % based on the total weight of the catalyst composition. For example, nickel oxide can be present in an amount from about 0.2 weight % to about 10 weight % based on the total weight of the catalyst composition. In another example, nickel oxide can be present in an amount from about 0.2 weight % to about 5 weight % based on the total weight of the catalyst composition. In another example, nickel oxide can be present in an amount from about 0.2 weight % to about 3 weight % based on the total weight of the catalyst composition.

[0042] In one aspect, the catalyst composition comprises tin oxide and nickel oxide. Thus, in one aspect, Q is tin oxide and nickel oxide. It is understood that Q can include all forms of oxides of tin (Sn) and nickel, as described herein. In this aspect, Q can be present in an amount from about 0.2 weight % to about 20 weight % based on the total weight of the catalyst composition, wherein tin oxide is present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition, and wherein nickel oxide is present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition. For example, Q can be present in an amount from about 0.2 weight % to about 10 weight % based on the total weight of the catalyst composition, wherein tin oxide is present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition, and wherein nickel oxide is present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition. In another example, Q can be present in an amount from about 0.2 weight % to about 5 weight % based on the total weight of the catalyst composition, wherein tin oxide is present in an amount from about 0.1 weight % to about 2.5 weight % based on the total weight of the catalyst composition, and wherein nickel oxide is present in an amount from about 0.1 weight % to about 2.5 weight % based on the total weight of the catalyst composition.

[0043] In one aspect, X can be present in an amount from about 0.05 weight % to about 10 weight % based on the total weight of the catalyst composition. For example, X can be present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition. In another example, X can be present in an amount from about 0.1 weight % to about 3 weight % based on the total weight of the catalyst composition. In yet another example, X can be present in an amount from about 0.1 weight % to about 1 weight % based on the total weight of the catalyst composition.

[0044] In one aspect, the catalyst composition comprises sulfate. Thus, in one aspect, X is sulfate. In one aspect, sulfate can be present in an amount from about 0.05 weight % to about 10 weight % based on the total weight of the catalyst composition. For example, sulfate can be present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition. In another example, sulfate can be present in an amount from about 0.1 weight % to about 3 weight % based on the total weight of the catalyst composition. In yet another example, sulfate can be present in an amount from about 0.1 weight % to about 1 weight % based on the total weight of the catalyst composition. In some of the methods disclosed herein, the catalyst composition disclosed herein is subjected to flue gas, such as coal fired flue gas, which contains sulfur compound. Such sulfur compounds, including sulfates, can under some circumstances be added to the catalyst during use. However, such additional amounts of sulfur or sulfate added during use are not included in the above values of sulfate present in the catalyst composition.

[0045] In one aspect, the catalyst composition comprises phosphate. Thus, in one aspect, X is phosphate. In one aspect, phosphate can be present in an amount from about 0.05 weight % to about 10 weight % based on the total weight of the catalyst composition. For example, phosphate can be present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition. In another example, phosphate can be present in an amount from about 0.1 weight % to about 3 weight % based on the total weight of the catalyst composition. In yet another example, phosphate can be present in an amount from about 0.1 weight % to about 1 weight % based on the total weight of the catalyst composition.

[0046] In one aspect, Q is tin oxide and X is sulfate. In another aspect, Q is tin oxide and X is phosphate.

[0047] In one aspect, Q is nickel oxide and X is sulfate. In another aspect, Q is nickel oxide and X is phosphate.

[0048] In one aspect, Q is tin oxide and nickel oxide and X is sulfate. In another aspect, Q is tin oxide and nickel oxide and X is phosphate.

[0049] In one aspect, Ml can be present in an amount from about 2.5 weight % to about 15 weight % based on the total weight of the catalyst composition, M2 can be present in an amount from about 0.5 weight % to about 10 weight % based on the total weight of the catalyst composition, M3 can be present in an amount from about 0.5 weight % to about 8 weight % based on the total weight of the catalyst composition, M4 can be the balance weight % of the catalyst composition based on the amounts of Ml, M2, M3, Q, and X, Q can be present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition, wherein tin oxide can be present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition, and wherein nickel oxide can be present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition, and X can be present in an amount from about 0.1 weight % to about 8 weight % based on the total weight of the catalyst composition.

[0050] In one aspect, Ml can be present in an amount from about 5 weight % to about 10 weight % based on the total weight of the catalyst composition, M2 can be present in an amount from about 0.5 weight % to about 2 weight % based on the total weight of the catalyst composition, M3 can be present in an amount from about 0.5 weight % to about 5 weight % based on the total weight of the catalyst composition, M4 can be the balance weight % of the catalyst composition based on the amounts of Ml, M2, M3, Q, and X, Q can be present in an amount from about 0.1 weight % to about 2.5 weight % based on the total weight of the catalyst composition, wherein tin oxide can be present in an amount from about 0.1 weight % to about 0.5 weight % based on the total weight of the catalyst composition, and wherein nickel oxide can be present in an amount from about 0.1 weight % to about 2 weight % based on the total weight of the catalyst composition, and X can be present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition.

[0051] In one aspect, the catalyst composition can be amorphous. In another aspect, the catalyst composition can be crystalline.

3. Method for Producing Ethylene

[0052] Disclosed herein is a method of producing ethylene. The disclosed method can be a cost-effective method for the production of ethylene. The disclosed method herein is performed with the catalyst composition disclosed herein. The method disclosed herein can also assist in remove CO2 from a flue gas, such as a coal fired flue gas. CO2 is a GHG and can be harmful to the environment. The method disclosed herein can utilize the CO2 from a flue gas, such as a coal fired flue gas, as a reactant for producing ethylene from ethane. Thus, ethane (gas) is added in the method disclosed herein. Coal fired flue gas contains -12.88 vol% CO2 with majority of the remaining component being N2. The method disclosed herein can also be performed with high purity CO2. The high purity CO2, excess of 90 vol% purity, can also be used in the method disclosed herein. The source for the high purity CO2 can vary, and includes CO2 captured from coal fired flue gas, which can have a purity of 95%.

[0053] The method disclosed herein utilizes favorable conditions for ethylene purity and yield. Disclosed herein is a method of producing ethylene comprising the step of: a) reacting ethane with a gas comprising CO2 in the presence of a catalyst composition disclosed herein, thereby producing ethylene. [0054] Ethane is present as a gas in the disclosed method. Thus, a reaction gas comprising ethane and CO ₂ is disclosed herein. A reaction gas is to be distinguished from a gas comprising CO2, which can include a high purity CO2 gas or a flue gas, such as a coal fired flue gas.

[0055] The gas comprising CO ₂ can contain a variety of volume % of CO ₂ . In one aspect, the gas comprising CO2 can have a high volume % of CO2, such as, for example, at least 90 volume % of CO2 _, at least 92 volume % of CO2 _, at least 95 volume % of CO2 _, at least 97 volume % of CO _2, or at least 99 volume % of CO ₂ . As discussed herein, the gas comprising a high volume % of CO ₂ can come from a variety of sources, including CO ₂ captured from coal fired flue gas.

[0056] In another aspect, the gas comprising CO ₂ can have a low volume % of CO ₂ , such as, for example, less than 90 volume % of CO _2, less than 80 volume % of CO _2, less than 70 volume % of CO2 _, less than 60 volume % of CO2 _, less than 50 volume % of CO2, less than 40 volume % of CO2, less than 30 volume % of CO2, less than 20 volume % of CO2, or less than 15 volume % of CO ₂ . For example, the gas comprising a low volume % of CO ₂ can be flue gas, such as coal fired flue gas.

[0057] The molar ratio between the CO ₂ and the ethane in the method can influence the selectivity of ethylene production, the conversion rate of CO ₂ , and the overall yield of the ethylene production. The molar ratio between the CO ₂ and the ethane can be altered depending on the volume % of CO ₂ in the gas comprising CO ₂ . In one aspect, the molar ratio between the CO ₂ and the ethane can be from about 1 : 1 to about 30: 1. For example, the molar ratio between the CO ₂ and the ethane can be from about 1 : 1 to about 20: 1. In another example, the molar ratio between the CO ₂ and the ethane can be from about 1 : 1 to about 15: 1. In yet another example, the molar ratio between the CO ₂ and the ethane can be from about 1 : 1 to about 10: 1.

In yet another example, the molar ratio between the CO2 and the ethane can be from about 1 : 1 to about 5: 1. In yet another example, the molar ratio between the CO2 and the ethane can be from about 1.5 : 1 to about 5: 1. In yet another example, the molar ratio between the CO2 and the ethane can be from about 5 : 1 to about 30: 1. In yet another example, the molar ratio between the CO2 and the ethane can be from about 10: 1 to about 30: 1. In yet another example, the molar ratio between the CO2 and the ethane can be from about 15: 1 to about 30: 1.

[0058] The performance of the method disclosed herein is better as compared to conventional catalysts. For example, wherein the method can have an ethylene selectivity of at least 80% and a CO ₂ conversion of at least 13% at a CCh to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas. In another example, wherein the method can have an ethylene selectivity of at least 85% and a CO ₂ conversion of at least 13% at a CO ₂ to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas. In yet another example, the method can have an ethylene selectivity of at least 85% and a CO2 conversion of at least 10% at a CChto ethane molar ratio of 3: 1 when the gas comprises 90 volume % of CO2. In yet another example, the method can have an ethylene selectivity of at least 90% and a CO2 conversion of at least 10% at a CC to ethane molar ratio of 3: 1 when the gas comprises 90 volume % of CO2.

[0059] The method disclosed herein can also have a higher ethylene yield for longer time, as compared to conventional catalysts. The stability of the catalyst disclosed herein provides for this desired performance of the disclosed method. In one aspect, the yield of ethylene can be at least 20% after at least 4 hrs of performing the method at a CC to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas. For example, the yield of ethylene can be at least 30% after at least 4 hrs of performing the method at a CO2 to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas.

[0060] In one aspect, the yield of ethylene can be at least 40% after at least 50 hrs of performing the method at a CO2 to ethane molar ratio of 1.5 : 1 when the gas is a coal fired flue gas. In another example, the yield of ethylene can be at least 40% after at least 100 hrs of performing the method at a CO2 to ethane molar ratio of 1.5 : 1 when the gas is a coal fired flue gas. In another example, the yield of ethylene can be at least 40% after at least 200 hrs of performing the method at a CO2 to ethane molar ratio of 1.5 : 1 when the gas is a coal fired flue gas. In yet another example, the yield of ethylene can be at least 40% after at least 300 hrs of performing the method at a CO2 to ethane molar ratio of 1.5 : 1 when the gas is a coal fired flue gas. In another example, the yield of ethylene can be sustained at at least 40% after performing the method for between 50 hrs to 400 hrs at a CO2 to ethane molar ratio of 1.5 : 1 when the gas is a coal fired flue gas. In another example, the yield of ethylene can be sustained at at least 40% after performing the method for between 100 hrs to 400 hrs at a CC to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas. In yet another example, the yield of ethylene can be sustained at at least 40% after performing the method for between 200 hrs to 400 hrs at a CC to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas.

[0061] In one aspect, the yield of ethylene can be at least 20% after at least 50 hrs of performing the method at a CO2 to ethane molar ratio of 1.5 : 1. In another example, the yield of ethylene can be at least 20% after at least 100 hrs of performing the method at a CO2 to ethane molar ratio of 1.5: 1. In another example, the yield of ethylene can be at least 20% after at least 200 hrs of performing the method at a CChto ethane molar ratio of 1.5: 1. In yet another example, the yield of ethylene can be at least 20% after at least 300 hrs of performing the method at a CO2 to ethane molar ratio of 1.5 : 1. In another example, the yield of ethylene can be sustained at at least 20% after performing the method for between 50 hrs to 300 hrs at a CO2 to ethane molar ratio of 1.5: 1. In another example, the yield of ethylene can be sustained at at least 20% after performing the method for between 100 hrs to 300 hrs at a CO2 to ethane molar ratio of 1.5: 1. In yet another example, the yield of ethylene can be sustained at at least 20% after performing the method for between 200 hrs to 300 hrs at a CC to ethane molar ratio of 1.5: 1.

[0062] In another aspect, the yield of ethylene can be at least 15% after at least 2 hrs of performing the method at a CO2 to ethane ratio of 3: 1 when the gas comprises 90 volume % of CO2. For example, the yield of ethylene can be at least 20% after at least 2 hrs of performing the method at a CO2 to ethane ratio of 3: 1 when the gas comprises 90 volume % of CO2. In another example, the yield of ethylene can be at least 20% after at least 2 hrs of performing the method at a CC to ethane ratio of 3: 1 when the gas comprises 90 volume % of CO2.

[0063] The reaction conditions of the method disclosed herein can be varied. In one aspect, the methods can be performed at a temperature from about 500 °C to about 750 °C. For example, the method can be performed at a temperature from about 500 °C to about 700 °C. In another example, the method can be performed at a temperature from about 600 °C to about 700 °C. In yet another example, the method can be performed at a temperature from about 650 °C to about 700 °C.

[0064] In another aspect, the method disclosed herein can be performed at a space velocity from about 3,000 to about 15,000 scc/gcat.hr. For example, the method disclosed herein can be performed at a space velocity from about 3,000 to about 12,000 scc/gcat.hr. In another example, the method disclosed herein can be performed at a space velocity from about 3,000 to about 9,000 scc/gcat.hr. In yet another example, the method disclosed herein can be performed at a space velocity from about 5,000 to about 15,000 scc/gcat.hr. In yet another example, the method disclosed herein can be performed at a space velocity from about 5,000 to about 12,000 scc/gcat.hr. In yet another example, the method disclosed herein can be performed at a space velocity from about 6,000 to about 10,000 scc/gcat.hr.

[0065] In one aspect, the method can be performed on an industrial scale.

4. Aspects

[0066] In view of the disclosure herein below are described certain more particularly described aspects of the inventions. These particularly recited aspects should not however be interpreted to have any limiting effect on any different claims containing different or more general teachings described herein, or that the“particular” aspects are somehow limited in some way other than the inherent meanings of the language and formulas literally used therein.

[0067] Aspect 1 : A catalyst composition comprising the formula:

M1M2M3M4Q - X wherein Ml is chromium oxide, wherein M2 is iron oxide, wherein M3 is cerium oxide, wherein M4 is zirconia, wherein Q is tin oxide or nickel oxide, or a combination thereof, and wherein X is sulfate or phosphate.

[0068] Aspect 2: The catalyst composition of aspect 1, wherein Ml is present in an amount from about 0.1 weight % to about 30 weight % based on the total weight of the catalyst composition.

[0069] Aspect 3: The catalyst composition of aspect 1, wherein Ml is present in an amount from about 5 weight % to about 15 weight % based on the total weight of the catalyst composition.

[0070] Aspect 4: The catalyst composition of any one of aspects 1-3, wherein M2 is present in an amount from about 0.1 weight % to about 30 weight % based on the total weight of the catalyst composition.

[0071] Aspect 5: The catalyst composition of any one of aspects 1-3, wherein M2 is present in an amount from about 0.5 weight % to about 5 weight % based on the total weight of the catalyst composition.

[0072] Aspect 6: The catalyst composition of any one of aspects 1-5, wherein M3 is present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition. [0073] Aspect 7: The catalyst composition of any one of aspects 1-5, wherein M3 is present in an amount from about 0.5 weight % to about 8 weight % based on the total weight of the catalyst composition.

[0074] Aspect 8: The catalyst composition of any one of aspects 1-7, wherein the amount of M4 is the balance weight % of the catalyst composition based on the amounts of Ml, M2, M3, Q, and X.

[0075] Aspect 9: The catalyst composition of any one of aspects 1-8, wherein Q is present in an amount from about 0.2 weight % to about 20 weight % based on the total weight of the catalyst composition, wherein tin oxide is present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition, and wherein nickel oxide is present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition.

[0076] Aspect 10: The catalyst composition of any one of aspects 1-8, wherein Q is present in an amount from about 0.2 weight % to about 10 weight % based on the total weight of the catalyst composition, wherein tin oxide is present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition, and wherein nickel oxide is present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition.

[0077] Aspect 11: The catalyst composition of any one of aspects 1-10, wherein X is present in an amount from about 0.05 weight % to about 10 weight % based on the total weight of the catalyst composition.

[0078] Aspect 12: The catalyst composition of any one of aspects 1-10, wherein X is present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition.

[0079] Aspect 13: The catalyst composition of any one of aspects 1-12, wherein X is sulfate.

[0080] Aspect 14: The catalyst composition of any one of aspects 1-12, wherein X is phosphate.

[0081] Aspect 15: The catalyst composition of any one of aspects 1-14, wherein Q is tin oxide.

[0082] Aspect 16: The catalyst composition of aspect 15, wherein tin oxide is present in an amount from about 0.2 weight % to about 20 weight % based on the total weight of the catalyst composition. [0083] Aspect 17: The catalyst composition of any one of aspects 1-14, wherein Q is nickel oxide.

[0084] Aspect 18: The catalyst composition of aspect 17, wherein nickel oxide is present in an amount from about 0.2 weight % to about 20 weight % based on the total weight of the catalyst composition.

[0085] Aspect 19: The catalyst composition of any one of aspects 1-14, wherein Q is tin oxide and nickel oxide.

[0086] Aspect 20: The catalyst composition of any one of aspects 1-19, wherein the catalyst composition has a surface area from about 10 m ² /g to about 200 m ² /g.

[0087] Aspect 21: The catalyst composition of any one of aspects 1-19, wherein the catalyst composition has a surface area from about 90 m ² /g to about 160 m ² /g.

[0088] Aspect 22: The catalyst composition of any one of aspects 1-21, wherein the catalyst composition has a pore size from about 3 nm to about 40 nm.

[0089] Aspect 23: The catalyst composition of any one of aspects 1-21, wherein the catalyst composition has a pore size from about 7 nm to about 15 nm.

[0090] Aspect 24: The catalyst composition of any one of aspects 1-23, wherein:

a) Ml is present in an amount from about 2.5 weight % to about 15 weight % based on the total weight of the catalyst composition, b) M2 is present in an amount from about 0.5 weight % to about 10 weight %

based on the total weight of the catalyst composition, c) M3 is present in an amount from about 0.5 weight % to about 8 weight % based on the total weight of the catalyst composition, d) M4 is the balance weight % of the catalyst composition based on the amounts of Ml, M2, M3, Q, and X, e) Q is present in an amount from about 0.1 weight % to about 10 weight % based on the total weight of the catalyst composition, wherein tin oxide is present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition, and wherein nickel oxide is present in an amount from about 0.1 weight % to about 5 weight % based on the total weight of the catalyst composition, and

1) X is present in an amount from about 0.1 weight % to about 8 weight % based on the total weight of the catalyst composition.

[0091] Aspect 25: The catalyst composition of any one of aspects 1-24, wherein the chromium oxide comprises (¾0 _3, iron oxide comprises Fe ₂ C> ₃ , nickel oxide comprises NiO, tin oxide comprises SnO, and cerium oxide comprises CeC .

[0092] Aspect 26: A method of producing ethylene comprising the step of:

a) reacting ethane with a gas comprising CO2 in the presence of the catalyst

composition of any one of aspects 1-23, thereby producing ethylene.

[0093] Aspect 27: The method of aspect 26, wherein the gas is a flue gas comprising less than 90 volume % of CO2.

[0094] Aspect 28: The method of aspect 26, wherein the gas a flue gas comprising less than 30 volume % of CO2.

[0095] Aspect 29: The method of any one of aspects 26-28, wherein the gas is coal fired flue gas.

[0096] Aspect 30: The method of aspect 26, wherein the gas comprises at least 90 volume % of CO2.

[0097] Aspect 31 : The method of aspect 26, wherein the gas comprises at least 95 volume % of C0 ₂ .

[0098] Aspect 32: The method of any one of aspects 26-31, wherein molar ratio between the CO2 and the ethane is from about 1 : 1 to about 30: 1.

[0099] Aspect 33: The method of any one of aspects 26-31, wherein molar ratio between the CO2 and the ethane is from about 1.5: 1 to about 5: 1.

[00100] Aspect 34: The method of any one of aspects 26-33, wherein the method has an ethylene selectivity of at least 80% and a CO2 conversion of at least 13% at a CC to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas. [00101] Aspect 35: The method of any one of aspects 26-33, wherein the method has an ethylene selectivity of at least 85% and a CO2 conversion of at least 10% at a CC to ethane molar ratio of 3: 1 when the gas comprises 90 volume % of CO2.

[00102] Aspect 36: The method of any one of aspects 26-35, wherein the yield of ethylene is at least 20% after at least 4 hrs of performing the method at a CO2 to ethane molar ratio of 1.5: 1 when the gas is a coal fired flue gas.

[00103] Aspect 37: The method of any one of aspects 26-35, wherein the yield of ethylene is at least 15% after at least 2 hrs of performing the method at a CO2 to ethane ratio of 3: 1 when the gas comprises 90 volume % of CO2.

5. Examples

[00104] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. The Examples are provided herein to illustrate the invention, and should not be construed as limiting the invention in any way.

1. EXPERIMENTAL PARAMETERS AND TESTING OF CATALYSTS

[00105] Various modifications and variations can be made to the compounds, composites, kits, articles, devices, compositions, and methods described herein. Other aspects of the compounds, composites, kits, articles, devices, compositions, and methods described herein will be apparent from consideration of the specification and practice of the compounds, composites, kits, articles, devices, compositions, and methods disclosed herein. It is intended that the specification and examples be considered as exemplary.

[00106] Catalyst 8Cr-5Ce-2Fe-Zr (0.5% S04, 0.7% SnO, 2% NiO) presented in the tables below was prepared using“Recipe 1” below. The other catalysts presented in the tables below and disclosed herein can be prepared using a procedure following“Recipe 1,” but adjusted for the specific metals oxides. “Recipe 2” below can also be used to prepare 8Cr-5Ce- 2Fe-Zr (0.5% S04, 0.7% SnO, 2% NiO) and the other disclosed catalysts herein and the catalysts presented in the tables below. [00107] (Recipe 1) A solution of 11.36g Zr0Ch.9H ₂ 0 was prepared in 330ml De ionized water under continuous stirring and at 50 °C (solution 1). The additional catalytic components, Cr, Fe and Ce were introduced by dissolving the required amounts of

CrCh.6H ₂ O(0.7g), FeCbAFhO (0.17g) and Ce(N0 ₃ ) ₃ .6Fh0 (0.33g) in solution 1, respectively.

[00108] In this process the amounts of ZrOCh.OFhO, CrCbAFhO, FeCbAFbO, and Ce(N03)3.6H20 can be varied to make catalysts with different amounts of the corresponding metal oxides.

[00109] In another beaker, a 5N 330ml NFbOH solution was prepared and maintained at 50 °C (solution 2). Solution 1 is added dropwise to solution 2 under vigorous stirring. The mixing of solution 1 and solution 2 triggers co-precipitation of metal hydroxides from solution 1 thereby forming a suspension at pH = 7-11. This suspension was allowed to settle for lhr at 50 °C. After that, the suspension was filtered in vacuum, washed 3 times with de-ionized water. The resulting filter cake was then dried in a rotary evaporator at 80°C in presence of n-butanol at 200mm Hg vacuum.

[00110] Ni and Sn were introduced as Ni(N0 ₃ ) ₂ .6H ₂ 0 (0.39g) and SnCh (0.06g) dissolved in 25 ml of absolute ethanol (solution 3). Solution 3 was then impregnated to the rotary evaporator dried sample. Excess ethanol is then dried at 80°C afterwards.

[00111] In this process the amounts of Ni(N03)2.6H20 and SnCh can be varied to make catalysts with different amounts of the corresponding metal oxides.

[00112] H ₂ SO ₄ (0.025g) was added to solution 3 to yield Sulfate (SO ₄ ) in the final catalyst composition.

[00113] In this process the amount of H ₂ SO ₄ can be varied to yield different amounts of sulfate in the final catalyst composition. In this process, H3PO4 (0.025g) can be used instead of H ₂ SO ₄ to yield phosphate in final catalyst composition.

[00114] The final dried sample was then calcined in static air at 650 °C for 2.5 hrs at 1 °C/min ramp rate. Following calcination the catalyst was pelletized and sieved to 600-800 micron size. The resulting catalysts had moderate surface areas (80-160 m ² /g).

[00115] Recipe 2 is an alternative process to Recipe 1. In Recipe 2, a solution of 11.36g Zr0Cb.9H ₂ 0 was precipitated using 5N NH4OH solution. The suspension is mainly composed of zirconium hydroxide, which was then filtered in vacuum, and washed 3 times using deionized water. The filter cake is then dried directly at 80 °C (recipe 2a) or placed in a NaOH (pH 14) or NH3 (pH 9) solution, boiled under reflux at 100 °C for 48-96 hrs and then dried at 80 °C (recipe 2b). The metal salts (Cr, Fe, Ce, Ni, and/or Sn, PO4 or SO4), which yields the corresponding metal oxides in the final product, in desired amounts, were then mixed in an aqueous solution which was then impregnated on the dried sample. This was followed by drying at 80 °C to evaporate excess water and calcination in static air at 650 °C for 2.5 hrs at 1 °C/min ramp rate. This resulted in final catalyst with low (10-80 m ² /g) and high (160-200 m ² /g) surface area catalysts from recipe 2a and 2b, respectively. Following calcination the catalyst is pelletized and sieved to 600-800 micron size.

[00116] The performance of the catalyst were tested under the following conditions: The catalytic performance testing was conducted at 650 °C, 1 atm, and 9,000 scc/gcat.hr. The molar ratio of CO2 to ethane is show in the tables below. Three different molar ratio of CO2 to ethane were used: 5: 1 (5), 3: 1 (3); and 1.5: 1 (1.5).

[00117] For the data represented as“captured” below a feed comprising 95% (ethane + CO2) and 5% N2 was used.

[00118] For the data represented as“direct flue gas” below the reactant feed comprised of pure ethane mixed with a -12.88 vol% CO2 in N2 gas stream. Ethane and CO2/N2 flow rates were determined from a pre-assigned molar ratio of CO2 to ethane, which resulted in a final feed composition ranging between 70-85% N2 and remaining ethane + CO2. Reaction runs using feed with such composition range (>70 % N2) are classified as“direct flue gas.”

[00119] In the Tables below the following terms are used:

“conversion” represents the conversion of mol% of ethane:

selectivity” represents selectivity to ethylene only (the only other unselective product is methane (CFE) (see equation 2 above));

“yield” represents maximum ethylene yield which is determined by multiplying“conversion” with“selectivity”;

“productivity” represents ethylene productivity in mmole ethylene/gram catalyst.hr in the product”;

“impurities” - Common feed components in ODH experiments are N2, CO2 and ethane. If any other flue gas impurities (e.g., Water, SO2, NO, O2) is used in feed they are listed in the impurity column. Maximum levels of impurities tested for catalytic study were 82 ppm SO2, 82 ppm NO, 3.25 mole % O2, 14.5 mole % H2O. These values were determined from coal fired flue gas composition widely reported in literature; “SO2 testing:” Effect of sulfur on catalyst performance was tested in three ways: Sulfating the catalyst - Catalyst composition lists SO4 or H2SO4 as components. Spiking gas feed with SO2 - Impurities lists Sox. Both sulfating catalyst and spiking gas feed with SO2 - SO4 appears in catalyst composition and SOx in the impurities column.

“H2O testing:” Effect of H2O on catalyst performance was tested by injecting H2O as a liquid through a syringe pump or by bubbling the feed gas through liquid water. The tested concentration in H2O in feed gas was between 0 - 15 vol%.

“O2 testing:” Effect of O2 on catalyst performance was tested by spiking feed gas with air containing desired levels of O2. The tested concentration in O2 in feed gas was between 0 - 5 vol%.

The numbers in the catalyst composition formulas represents the weight % of the oxide form, wherein the balance is Zr (zirconia). For example 8Cr-5Ce-2Fe-Zr (0.5% S04, 0.7% SnO, 2% NiO) denotes 8 wt % chromium oxide, 5 wt% cerium oxide, 2 wt% iron oxide, 0.5 wt% sulfate, 0.7 wt% tin oxide, 2 wt% nickel oxide, and the balance being zirconia. a. Direct Flue Gas

[00120] Table 1 shows data for direct flue gas testing at a molar ratio of CO2 to ethane of 5: 1 (5).

TABLE 1

[00121] Table 2 shows data for direct flue gas testing at a molar ratio of CO2 to ethane of 1.5: 1 (1.5), unless a different R value is indicated within parenthesis follow the catalyst formula. TABLE 2

b. Captured

Table 3 shows data for captured testing at a molar ratio of CO2 to ethane of 5: 1 (5).

TABLE 3

[00122] Table 4 shows data for captured testing at a molar ratio of CO2 to ethane of 3: 1

(3).

TABLE 4

[00123] Table 5 shows data for captured testing at a molar ratio of CO2 to ethane of 1.5: 1 (1.5), unless a different R value is indicated within parenthesis follow the catalyst formula.

TABLE 5

[00124] The data presented in Tables 1-5 show that catalysts disclosed herein have a substantially superior overall performance as compared to conventional catalysts. One parameter to identify a suitable catalyst candidate for commercial use is the product (ethylene) “yield” listed in Table 1-5. Catalyst“productivity” is another parameter represented as mmoles of products formed per time per mass of catalyst. This number for the catalysts disclosed herein ranges from 2.91 to 23.84 (Table 1-5). Other superior attributes of the disclosed catalysts that set them apart from literature catalyst are long term stability (100+ hrs of continuous operation), regenerability (15+ cycles of continuous operation and catalyst regeneration without loss of activity) and tolerance to impurities (SO2, NO, O2) present in industrial feedstock. The yield, productivity, and long term stability, alone or in combination, of the catalyst disclosed herein are substantially superior, as compared to conventional catalysts.

[00125] FIG. 1 shows long term stability test data of an exemplary non-limiting catalyst disclosed herein under direct flue gas testing at a molar ratio of CO2 to ethane of 1.5: 1. The catalyst used to generate the data in FIG. 1 was 8Cr-2Fe-5Ce-Zr (0.5% SO4, 0.5% NiO and 0.1% SnO). Operating condition: 650 °C, 1 atm and 9,000 scc/gcat.hr. Two reactants were mixed together: (i) 12.88 vol% CO2 in N2 with 80 ppm S02 and 80 ppm NO and (ii) ethane.

The primary X-axis shows number of cycles. Each cycle represents one continuous reaction run followed by catalyst regeneration. The secondary X-axis shows total time on stream in hrs. The data in FIG. 1 shows that the tested catalyst has excellent stability under the direct flue gas testing.

[00126] FIG. 2 shows long term stability test data of catalyst under captured CO2 testing at a molar ratio of C02 to ethane of 1.5: 1. The catalyst used to generate the data in FIG. 2 was 8Cr-2Fe-5Ce-Zr (3% SO4, 0.5% NiO and 0.1% SnO). Operating condition: 650 °C, 1 atm and 9,000 scc/gcat.hr. Two reactants were mixed together: (i) 95% CO2 in N2 and (ii) ethane. The primary X-axis shows number of cycles. Each cycle represents one continuous reaction run followed by catalyst regeneration. The secondary X-axis shows total time on stream in hrs. The data in FIG. 2 shows that the tested catalyst has excellent stability under the captured CO2 testing.

[00127] FIG. 3 shows the effect of H2O being present in the reactant feed under direct flue gas testing. The catalyst used to generate the data in FIG. 3 was 8Cr-5Ce-2Fe-Zr (0.5%

SO ₄ , 1% NiO and 0.2% SnO). X-axis shows the number of reaction cycles (1 cycle = 1 catalytic run followed by regeneration). CO2: ethane = 1.5. The primary Y-axis shows ethylene yield obtained from multiple cycles. The secondary Y-axis shows the H20:C02 ratio in the feed. H2O was introduced to the reaction with a syringe pump as liquid. CO ₂ was introduced as part of simulated direct flue gas (12.88% CO ₂ in N2 with 80ppm SO ₂ and 80 ppm NO).

[00128] FIGs. 4A and 4B show normalized data for (4A) CO2 conversion and (4B) ethylene yield with respect to 02:C02 ratio in direct flue gas feed reactant for a catalyst without Ce. The catalyst used to generate the data in FIGs. 4A and 4B was 2Cr-4Fe-Zr (0.5% NiO).