# US 2018/0021758 A1 · Core-shell support, method for producing the same, catalyst for purification of exhaust gas using the core-shell support, method for producing the same, and method for purification of exhaust gas using the catalyst for purification of exhaust gas

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- Number: US 2018/0021758 A1
- Document ID: US20180021758A1
- Status: Published application
- Kind: A1
- Application number: 15/550,148
- Filed: 2016-03-01
- Published: 2018-01-25
- Earliest claimed: 2015-03-12
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Naoki KUMATANI; Toshitaka TANABE; Masahide MIURA
- Web page: https://patentgrep.com/patent/US20180021758A1

## CPC

- B01J 23/63: with rare earths or actinides
- B01D 53/94: by catalytic processes
- B01D 53/9413: {Processes characterised by a specific catalyst}
- B01D 53/9422: {for removing nitrogen oxides by NOx storage or reduction by cyclic switching between lean and rich exhaust gases (LNT, NSC, NSR)}
- B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof}
- B01J 23/464: {Rhodium}
- B01J 35/397: {Egg shell like}
- B01J 37/0215: {Coating}
- B01J 37/0244: {Coatings comprising several layers}
- C01G 25/00: Compounds of zirconium
- C01G 25/006: {Compounds containing zirconium, with or without oxygen or hydrogen, and containing two or more other elements}
- C01G 25/02: Oxides
- B01D 2255/10: Noble metals or compounds thereof
- B01D 2255/1025: Rhodium
- B01D 2255/206: Rare earth metals
- B01D 2255/2061: Yttrium
- B01D 2255/2063: Lanthanum
- B01D 2255/2066: Praseodymium
- B01D 2255/2068: Neodymium
- B01D 2255/20715: Zirconium
- B01D 2255/407: Zr-Ce mixed oxides
- B01D 2255/9022: Two layers
- B01D 2255/908: O2-storage component incorporated in the catalyst
- B01D 2257/502: Carbon monoxide
- B01D 2257/702: Hydrocarbons
- B01J 35/40: characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77)
- B01J 35/45: Nanoparticles
- B01J 35/735: {Pyrochlore-type A2B2O7}
- B01J 35/77: Compounds characterised by their crystallite size
- 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 2004/84: one phase coated with the other
- Y02T 10/12: Improving ICE efficiencies
- 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
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A core-shell support, comprising: a core which comprises at least one oxygen storage/release material selected from the group consisting of ceria-zirconia based solid solutions and alumina-doped ceria-zirconia based solid solutions; and a shell which comprises a rare earth-zirconia based composite oxide represented by a composition formula: (Re1-xCex)2Zr2O7+x (where Re represents a rare earth element, and x represents a number of 0.0 to 0.8) and with which an outside of the core is coated, the rare earth-zirconia based composite oxide comprising crystal particles having a pyrochlore structure, and the rare earth-zirconia based composite oxide having an average crystallite diameter of 3 to 9 nm.

## Claims

### Claim at position 1

-13. (canceled)

### Claim 14

A core-shell support, comprising:
a core which comprises at least one oxygen storage/release material selected from alumina-doped ceria-zirconia based solid solutions; and
a shell which comprises a rare earth-zirconia based composite oxide represented by a composition formula: (Re1-xCex)2Zr2O7+x (where Re represents a rare earth element being at least one element selected from the group consisting of La, Nd, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc and Y, and x represents a number of 0.0 to 0.8) and with which an outside of the core is coated,
the rare earth-zirconia based composite oxide comprising crystal particles having a pyrochlore structure, and
the rare earth-zirconia based composite oxide having an average crystallite diameter of 3 to 9 nm, wherein
an amount of the rare earth-zirconia based composite oxide constituting the shell is 4 to 24 parts by mass relative to 100 parts by mass of the oxygen storage/release material constituting the core.

### Claim 15 (depends on 14)

The core-shell support according to claim 14, wherein
x in the composition formula is a number of 0.5 to 0.7.

### Claim 16 (depends on 14)

The core-shell support according to claim 14, wherein
Re in the composition formula is at least one element selected from the group consisting of La, Nd, Pr, and Y.

### Claim 17 (depends on 14)

A catalyst for purification of exhaust gas, comprising:
the core-shell support according to claim 14; and
a noble metal supported on the core-shell support.

### Claim 18 (depends on 17)

The catalyst for purification of exhaust gas according to claim 17, wherein
the noble metal is Rh.

### Claim 19 (depends on 14)

A catalyst for purification of exhaust gas, comprising:
a substrate; and
a catalyst layer disposed on the substrate, wherein
the catalyst layer comprises the core-shell support according to claim 14, alumina, and a noble metal.

### Claim 20 (depends on 19)

The catalyst for purification of exhaust gas according to claim 19, wherein
the catalyst layer, which comprises the core-shell support, the alumina and the noble metal, is a rhodium-containing catalyst layer containing Rh as the noble metal, and
a palladium-containing catalyst layer containing an alumina-doped ceria-zirconia based solid solution, alumina, and Pd is disposed between the substrate and the rhodium-containing catalyst layer.

### Claim 21 (depends on 14)

A method for producing the core-shell support according to claim 14, comprising:
a solution preparation step of preparing a solution containing a rare earth element salt and a zirconium salt;
a first coating step of bringing the prepared solution into contact with a powder of at least one oxygen storage/release material selected from alumina-doped ceria-zirconia based solid solutions to obtain a core-shell powder supporting the prepared solution in an amount which gives, after calcination to an oxide, 1 to 8 parts by mass of the rare earth-zirconia based composite oxide constituting a part of the shell relative to 100 parts by mass of the oxygen storage/release material constituting the core, followed by calcination at a temperature in a range from 600 to 1100° C. and then by grinding; and
a second coating step of bringing the prepared solution into contact with the obtained core-shell powder to obtain the core-shell powder additionally supporting the prepared solution in an amount which gives, after calcination to an oxide, 1 to 8 parts by mass of the rare earth-zirconia based composite oxide constituting a part of the shell relative to 100 parts by mass of the oxygen storage/release material constituting the core, followed by calcination at a temperature in a range from 600 to 1100° C. and then by grinding,
the core-shell support being obtained by performing the second coating step until an amount of the rare earth-zirconia based composite oxide constituting the shell after the calcination to the oxide reaches 4 to 24 parts by mass relative to 100 parts by mass of the oxygen storage/release material constituting the core.

### Claim 22 (depends on 17)

A method for producing the catalyst for purification of exhaust gas according to claim 17, comprising:
a solution preparation step of preparing a solution containing a rare earth element salt and a zirconium salt;
a first coating step of bringing the prepared solution into contact with a powder of at least one oxygen storage/release material selected from alumina-doped ceria-zirconia based solid solutions to obtain a core-shell powder supporting the prepared solution in an amount which gives, after calcination to an oxide, 1 to 8 parts by mass of the rare earth-zirconia based composite oxide constituting a part of the shell relative to 100 parts by mass of the oxygen storage/release material constituting the core, followed by calcination at a temperature in a range from 600 to 1100° C. and then by grinding; and
a second coating step of bringing the prepared solution into contact with the obtained core-shell powder to obtain the core-shell powder additionally supporting the prepared solution in an amount which gives, after calcination to an oxide, 1 to 8 parts by mass of the rare earth-zirconia based composite oxide constituting a part of the shell relative to 100 parts by mass of the oxygen storage/release material constituting the core, followed by calcination at a temperature in a range from 600 to 1100° C. and then by grinding,
the core-shell support being obtained by performing the second coating step until an amount of the rare earth-zirconia based composite oxide constituting the shell after the calcination to the oxide reaches 4 to 24 parts by mass relative to 100 parts by mass of the oxygen storage/release material constituting the core, and then
the catalyst for purification of exhaust gas being obtained by bringing a noble metal salt solution into contact with the core-shell support.

### Claim 23 (depends on 17)

A method for purification of exhaust gas, comprising:
purifying an exhaust gas emitted from an internal combustion engine by bringing the exhaust gas into contact with the catalyst for purification of exhaust gas according to claim 17.

### Claim 24 (depends on 19)

A method for purification of exhaust gas, comprising:
purifying an exhaust gas emitted from an internal combustion engine by bringing the exhaust gas into contact with the catalyst for purification of exhaust gas according to claim 19.