# US 12,214,333 B2 · Mixed oxide based on cerium and zirconium

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- Number: US 12,214,333 B2
- Document ID: US12214333B2
- Status: Granted
- Kind: B2
- Application number: 17/627,151
- Filed: 2020-07-15
- Published: 2022-09-22
- Granted: 2025-02-04
- Earliest claimed: 2020-07-15
- Assignees: Rhodia Operations
- Applicants: Rhodia Operations
- Inventors: Simon Ifrah; Rui Jorge Coelho Marques; Wei Li; Ling Zhu
- Web page: https://patentgrep.com/patent/US12214333B2

## CPC

- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01J 23/10: of rare earths
- B01D 53/945: {characterised by a specific catalyst}
- B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof}
- B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths
- B01J 35/613: {10-100 m2/g}
- B01J 35/635: {0.5-1.0 ml/g}
- B01J 35/638: {more than 1.0 ml/g}
- B01J 37/0018: {Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)}
- B01J 37/0027: {Powdering}
- B01J 37/031: {Precipitation}
- B01J 37/04: Mixing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/088: {Decomposition of a metal salt}
- 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}
- B01D 2255/102: Platinum group metals
- B01D 2255/2061: Yttrium
- B01D 2255/2063: Lanthanum
- B01D 2255/2065: Cerium
- B01D 2255/20715: Zirconium
- B01D 2255/2092: Aluminium
- B01D 2255/407: Zr-Ce mixed oxides
- B01D 2255/9155: Wall flow filters
- B01D 2255/9202: Linear dimensions
- B01D 2255/9207: Specific surface
- B01D 2258/012: Diesel engines and lean burn gasoline engines
- B01D 2258/014: Stoichiometric gasoline engines
- C01P 2002/52: containing elements as dopants
- C01P 2002/54: one element only
- C01P 2004/51: Particles with a specific particle size distribution
- C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer
- C01P 2006/12: Surface area
- C01P 2006/14: Pore volume
- C01P 2006/22: Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability
- Y02T 10/12: Improving ICE efficiencies
- 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)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- 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 mixed oxide, a catalytic composition, a catalytic wall-flow monolith, the use of the mixed oxide and the process of the preparation of the mixed oxide. The mixed oxide comprises zirconium, cerium, lanthanum and optionally at least one rare earth element other than cerium and other than lanthanum. The catalytic composition and the wall-flow monolith comprise the particles of the mixed oxide. The use of the mixed oxide is in the preparation of a coating on a filter. The process of preparation of the mixed oxide consists jet milling. The mixed oxide is a compromise between a calibrated size and a low viscosity when in the form of an aqueous slurry while retaining a high specific surface area and a high pore volume.

## Claims

### Claim 1

A mixed oxide comprising zirconium, cerium, lanthanum and optionally at least one rare earth element other than cerium and other than lanthanum (RE) with the following proportion:
between 8.0% and 45.0% by weight of cerium;
between 1.0% and 15.0% by weight of lanthanum;
up to 15.0% by weight of the at least one rare earth element other than cerium and other than lanthanum;
the total proportion of lanthanum and the at least one rare earth element(s) other than cerium and other than lanthanum being lower than or equal to 25.0%;
the remainder as zirconium;
the proportions of the cerium, zirconium, lanthanum, and RE being given by weight of oxide relative to the mixed oxide as a whole,
the mixed oxide exhibiting the following properties after calcination in air at 1100° C. for 4 hours:
a specific surface area (S1100° C./4 h) between 25 m2/g and 50 m2/g;
a pore volume (PV0-300 nm) determined by mercury porosimetry for pores having a diameter below 300 nm between 0.50 cm3/g and 0.90 cm3/g;
the mixed oxide being in the form of particles with the following properties:
a d50 between 1.0 μm and 2.5 μm;
a d90 between 2.0 μm and 9.0 μm
wherein the above mentioned elements are present in the mixed oxide as oxides.

### Claim 2

A mixed oxide consisting of a combination of oxides of zirconium; of cerium; of lanthanum; optionally of at least one rare earth element other than cerium and other than lanthanum (RE); and optionally of hafnium, with the following proportion:
between 8.0% and 45.0% by weight of cerium;
between 1.0% and 15.0% by weight of lanthanum;
up to 15.0% by weight of the at least one rare earth element other than cerium and other than lanthanum; the total proportion of lanthanum and the at least one rare earth element(s) other than cerium and lanthanum being lower than or equal to 25.0%;
a proportion of hafnium lower than or equal to 2.5%; the remainder as zirconium;
the proportions of the cerium, zirconium, lanthanum, and RE being given by weight of oxide relative to the mixed oxide as a whole,
exhibiting the following properties after calcination in air at 1100° C. for 4 hours:
a specific surface area (S1100° C./4 h) between 25 m2/g and 50 m2/g;
a pore volume determined by mercury porosimetry for pores having a diameter below 300 nm between 0.50 cm3/g and 0.90 cm3/g;
the mixed oxide being in the form of particles with the following properties:
a d50 between 1.0 μm and 2.5 μm;
a d90 between 2.0 μm and 9.0 μm.

### Claim 3 (depends on 1)

The mixed oxide according to claim 1 characterized by the following proportions:
between 18.0% and 37.0% by weight of cerium;
between 3.0% and 9.0% by weight of lanthanum;
the remainder as zirconium;
or
between 30.0% and 45.0% by weight of cerium;
between 3.0% and 9.0% by weight of lanthanum;
between 3.0% and 9.0% by weight of at least one rare earth element other than cerium and other than lanthanum (RE);
the remainder as zirconium;
or
between 20.0% and 35.0% by weight of cerium;
between 3.0% and 9.0% by weight of lanthanum;
between 3.0% and 15.0% by weight of at least one rare earth element other than cerium and other than lanthanum (RE);
the remainder as zirconium.

### Claim 4 (depends on 1)

The mixed oxide according to claim 1 further comprising hafnium, the proportion of hafnium in the mixed oxide being lower than or equal to 2.5%, and the proportion being given by weight of oxide relative to the mixed oxide as a whole.

### Claim 5 (depends on 1)

The mixed oxide according to claim 1 wherein the proportion of cerium is between 18.0% and 37.0% by weight.

### Claim 6 (depends on 1)

The mixed oxide according to claim 1 wherein the proportion of zirconium is higher than 45% by weight.

### Claim 7 (depends on 1)

The mixed oxide according to claim 1 comprising a weight ratio of ZrO2/CeO2>1.0.

### Claim 8 (depends on 1)

The mixed oxide according to claim 1 wherein the d50 is between 1.0 μm and less than 2.5 μm.

### Claim 9 (depends on 1)

The mixed oxide according to claim 1 wherein the particles exhibit a d10 lower than or equal to 1.0 μm.

### Claim 10 (depends on 1)

The mixed oxide according to claim 1 wherein the particles exhibit a d10 higher than or equal to 0.2 and lower than or equal to 1.0 μm.

### Claim 11 (depends on 1)

The mixed oxide according to claim 1 wherein the particles exhibit a d99 lower than or equal to 20.0 and higher than or equal to 5.0 μm.

### Claim 12 (depends on 1)

The mixed oxide according to claim 1 wherein the particles exhibit a d99 higher than or equal to 5.0 μm.

### Claim 13 (depends on 1)

The mixed oxide according to claim 1 exhibiting a total pore volume determined by mercury porosimetry after calcination in air at 1 100° C. for 4 hours between 1.40 cm3/g and 3.00 cm3/g.

### Claim 14 (depends on 1)

The mixed oxide according to claim 1 wherein the viscosity of a dispersion containing 43.0 wt % of particles of the mixed oxide in water and exhibiting a pH of 4.0±0.1 is lower than or equal to 20.0 cP, the viscosity being measured at 20° C.±1° C. and for a shear rate applied between 5.0 and 10.0 s−1.

### Claim 15 (depends on 1)

The mixed oxide according to claim 1 wherein after calcination in air at 1100° C. for 4 hours, the mixed oxide exhibits a specific surface area (S1100° C./4 h)) between 28 and 50 m2/g.

### Claim 16 (depends on 1)

The mixed oxide according to claim 1 wherein after calcination in air at 1100° C. for 4 hours, the mixed oxide exhibits a specific surface area (S1100° C./4 h) between 30 and 50 m2/g.

### Claim 17 (depends on 1)

The mixed oxide according to claim 1 wherein after calcination in air at 1100° C. for 4 hours, the mixed oxide exhibits a pore volume determined by mercury porosimetry for the pores having a diameter below 300 nm (PV0-300 nm) between 0.50 cm3/g and 0.70 cm3/g.

### Claim 18 (depends on 1)

The mixed oxide according to claim 1 wherein after calcination in air at 1100° C. for 4 hours, the mixed oxide exhibits a total pore volume determined by mercury porosimetry which is between 1.50 cm3/g and 2.50 cm3/g.

### Claim 19 (depends on 1)

The mixed oxide according to claim 1 wherein after calcination in air at 1100° C. for 4 hours, the mixed oxide exhibits a total pore volume determined by mercury porosimetry of at least 1.60 cm3/g.

### Claim 20 (depends on 1)

The mixed oxide according to claim 1 wherein RE is Y or Nd or a combination of Y and Nd.

### Claim 21 (depends on 1)

The mixed oxide according to claim 1 wherein the d50 is between 1.0 μm and 2.2 μm.

### Claim 22 (depends on 1)

The mixed oxide according to claim 1 wherein the d50 is between 1.0 μm and 2.0 μm.

### Claim 23 (depends on 1)

The mixed oxide according to claim 1 wherein the d50 is between 1.5 μm and 2.0 μm.

### Claim 24 (depends on 1)

The mixed oxide according to claim 1 wherein the d90 is between 2.0 μm and 8.0 μm.

### Claim 25 (depends on 1)

The mixed oxide according to claim 1 wherein the d90 is between 2.0 μm and 7.0 μm.

### Claim 26 (depends on 1)

The mixed oxide according to claim 1 wherein the d90 is between 3.0 μm and 8.0 μm.

### Claim 27 (depends on 1)

The mixed oxide according to claim 1 wherein the d90 is between 3.0 μm and 7.0 μm.

### Claim 28 (depends on 1)

A catalytic composition comprising:
alumina;
one or more platinum group metals; and
the mixed oxide according to claim 1.

### Claim 29 (depends on 28)

A catalytic wall-flow monolith comprising a porous support and the catalytic composition of claim 28 on the surface of the support.

### Claim 30 (depends on 1)

A method of preparing a catalytic converter or a catalytic wall-flow monolith comprising:
depositing a catalytic composition as a layer on a solid support;
wherein the catalytic composition comprises the mixed oxide according to claim 1.

### Claim 31 (depends on 1)

A process of preparing the mixed oxide according to claim 1 comprising the following steps:
(a1) reacting an aqueous solution comprising sulphate anion (SO42−), a zirconium chloride salt, a cerium salt and optionally at least one salt of a rare earth element other than cerium and other than lanthanum with an aqueous basic solution to form a precipitate;
(b1) separating off the precipitate obtained at the end of step (a1) from an aqueous medium;
(c1) heating the precipitate obtained at the end of step (b1), in an aqueous medium and optionally in the presence of a lanthanum salt with a basic compound;
(d1) adding to the mixture obtained at the end of step (c1), optionally with a lanthanum salt;
(e1) adding an organic texturing agent to the mixture obtained at the end of step (d1);
(f1) separating off a solid material obtained at the end of step (e1) from the aqueous medium and calcining the separated solid material in air;
(g1) jet milling the seperated solid material obtained at the end of step (f1).

### Claim 32 (depends on 31)

The process according to claim 31 wherein the zirconium chloride salt is ZrOCl2.

### Claim 33 (depends on 31)

The process according to claim 31 wherein the molar ratio of SO42−/(Zr+Ce) of the aqueous solution of step (a1) is in the range of 0.5-1.0.

### Claim 34 (depends on 31)

The process of preparing the mixed oxide according to claim 31, further comprising jet milling the mixed oxide.