Title:
OXYGEN ABSORBING AND RELEASING MATERIAL, CATALYST, EXHAUST GAS PURIFYING SYSTEM, AND EXHAUST GAS TREATMENT METHOD
Document Type and Number:
WIPO Patent Application WO/2019/088302
Kind Code:
A1
Abstract:
The purpose of the present invention is to provide: an oxygen absorbing and releasing material comprising a ceria/zirconia-based composite oxide having improved HC and NOx purification performance; and a three-way catalyst capable of reducing a NOx discharge amount. To solve said problem, the present invention provides an oxygen absorbing and releasing material, which is a ceria/zirconia-based composite oxide, containing 0.1-20 mol% (exclusive of 20 mol%) of Gd2O3 and has an ionic conductivity of 2×10-5 S/cm or more at 400°C. In addition to the above, an oxygen absorbing and releasing material is provided which is characterized in that a molar ratio of cerium to zirconium is 0.2-0.6 in terms of cerium/(cerium+zirconium), and an oxygen absorbing and releasing speed (OSC speed) Δt50 is 20.0 seconds or more or an oxygen absorbing and releasing amount (OSC amount) is 300 μmol-O2/g or more. Furthermore, by applying the oxygen absorbing and releasing material to a catalyst, it is possible to obtain a catalyst which assists in the purification of exhaust gas that constantly changes according to the driving state and has a higher hazardous ingredient purification performance of precious metals than before. In particular, it is possible to obtain an automobile exhaust gas purification system having excellent CO, NOx and HC purification capacity.
Inventors:
AIHARA KEIGO (JP)
ITOH TOMOHARU (JP)
KONNO HIROFUMI (JP)
NAGAOKA SHUHEI (JP)
YAMADA TAKASHI (JP)
ITOH TOMOHARU (JP)
KONNO HIROFUMI (JP)
NAGAOKA SHUHEI (JP)
YAMADA TAKASHI (JP)
Application Number:
PCT/JP2018/041238
Publication Date:
May 09, 2019
Filing Date:
November 06, 2018
Export Citation:
Assignee:
NIPPON DENKO (JP)
JOHNSON MATTHEY PLC (GB)
JOHNSON MATTHEY PLC (GB)
International Classes:
C01G25/00; B01D53/94; B01J23/63; B01J32/00; F01N3/10
Domestic Patent References:
| WO2017130917A1 | 2017-08-03 | |||
| WO2012105454A1 | 2012-08-09 |
Foreign References:
| JP2017042752A | 2017-03-02 | |||
| JP2013525255A | 2013-06-20 | |||
| JP2009537432A | 2009-10-29 | |||
| JP2004529837A | 2004-09-30 | |||
| JP2012519060A | 2012-08-23 | |||
| JP2017087086A | 2017-05-25 | |||
| JP2012180271A | 2012-09-20 | |||
| JP2011121851A | 2011-06-23 | |||
| JP2006256912A | 2006-09-28 | |||
| US20180065110A1 | 2018-03-08 |
Other References:
"Materials", INFLUENCE OF CERIA DOPING ON OXYGEN RELAXATION AND OXIDE ION CONDUCTION IN YTTRIA STABILIZED CUBIC ZIRCONIA, vol. 60, no. 3, March 2011 (2011-03-01), pages 194 - 197
See also references of EP 3708541A4
See also references of EP 3708541A4
Attorney, Agent or Firm:
AOKI, Atsushi et al. (JP)
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