# US 9,751,075 B2 · Ceria-zirconia complex oxide material and method for producing same

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- Number: US 9,751,075 B2
- Document ID: US9751075B2
- Status: Granted
- Kind: B2
- Application number: 14/738,384
- Filed: 2015-06-12
- Published: 2015-12-31
- Granted: 2017-09-05
- Earliest claimed: 2014-06-26
- Assignees: Toyota Jidosha Kabushiki Kaisha; National University Corporation Nagoya University
- Applicants: Toyota Jidosha Kabushiki Kaisha; National University Corporation Nagoya University
- Inventors: Satoshi Nagao; Takashi Minami; Shinichi Matsumoto; Hirohito Hirata; Masakuni Ozawa
- Web page: https://patentgrep.com/patent/US9751075B2

## CPC

- B01J 23/10: of rare earths
- B01D 53/9413: {Processes characterised by a specific catalyst}
- B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof}
- B01J 23/002: {Mixed oxides other than spinels, e.g. perovskite}
- B01J 23/63: with rare earths or actinides
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 35/45: Nanoparticles
- B01J 35/735: {Pyrochlore-type A2B2O7}
- B01J 35/77: Compounds characterised by their crystallite size
- B01J 37/031: {Precipitation}
- B01J 37/04: Mixing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/10: in the presence of water, e.g. steam
- B01J 37/12: Oxidising
- B01J 37/16: Reducing
- B01J 37/18: with gases containing free hydrogen
- C01G 25/02: Oxides
- B01D 2255/102: Platinum group metals
- B01D 2255/106: Gold
- B01D 2255/20715: Zirconium
- B01D 2255/20738: Iron
- B01D 2255/20753: Nickel
- B01D 2255/20761: Copper
- B01D 2255/407: Zr-Ce mixed oxides
- B01D 2255/908: O2-storage component incorporated in the catalyst
- B01D 2255/92: Dimensions
- B01D 2255/9202: Linear dimensions
- B01J 2235/00: Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
- B01J 2235/15: X-ray diffraction
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- C01P 2002/36: pyrochlore-type (A2B2O7)
- C01P 2002/60: Compounds characterised by their crystallite size
- C01P 2002/76: by a space-group or by other symmetry indications
- C01P 2002/82: by IR- or Raman-data
- C01P 2004/03: obtained by SEM
- C01P 2004/04: obtained by TEM, STEM, STM or AFM
- C01P 2004/82: two phases having the same anion, e.g. both oxidic phases
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

A satisfactory oxygen storage material and a method for producing it are provided. The oxygen storage material comprises zirconia particles with a ceria-zirconia complex oxide supported on the zirconia particles. The ceria-zirconia complex oxide includes a pyrochlore phase and has a mean crystallite diameter of 10 nm to 22.9 nm.

## Claims

### Claim 1

A method for producing an oxygen storage material, the oxygen storage material comprising:
zirconia particles and
a ceria-zirconia complex oxide supported on the zirconia particles, wherein the ceria-zirconia complex oxide includes a pyrochlore phase and has a mean crystallite diameter of 10 nm to 22.9 nm,
the method comprising the following steps in order:
(i) a step of preparing an aqueous solution containing:
a water-soluble cerium salt,
a water-soluble zirconium salt or oxyzirconium salt,
a complexing agent that is an alkylcarboxylic acid and/or an alkylcarboxylic acid salt, and
zirconia particles,
(ii) adding an aqueous alkali solution to the aqueous solution of (i),
(iii) holding the aqueous solution mixture of (ii) at a temperature of 180° C. to 220° C. for 0.5 hours to 72 hours to produce a solid product by precipitation,
(iv) holding the solid product at a temperature of 500° C. to 700° C. for 1 hour to 5 hours and then at a temperature of 700° C. to 1100° C. for 1 hour to 5 hours, and
(v) further subjecting the solid product to temperature-programmed reduction treatment.