# US 2018/0021759 A1 · Cerium-zirconium composite oxide, preparation method therefor, and application of catalyst

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- Number: US 2018/0021759 A1
- Document ID: US20180021759A1
- Status: Published application
- Kind: A1
- Application number: 15/546,152
- Filed: 2016-01-26
- Published: 2018-01-25
- Earliest claimed: 2015-02-09
- Assignees: Grirem Advanced Materials Co., Ltd.
- Applicants: Grirem Advanced Materials Co., Ltd.
- Inventors: Xiaowei Huang; Qi Wang; Mei Yue; Qiang Zhong; Lei Wang; Yongke Hou; Meisheng Cui
- Web page: https://patentgrep.com/patent/US20180021759A1

## CPC

- B01J 23/83: with rare earths or actinides
- B01D 53/86: Catalytic processes
- B01D 53/94: by catalytic processes
- B01J 23/10: of rare earths
- B01J 23/34: Manganese
- B01J 23/63: with rare earths or actinides
- B01J 35/45: Nanoparticles
- B01J 35/50: characterised by their shape or configuration
- B01J 35/51: Spheres
- B01J 35/58: Fabrics or filaments
- B01J 35/613: {10-100 m2/g}
- B01J 37/03: Precipitation; Co-precipitation
- B01J 37/038: {to form slurries or suspensions, e.g. a washcoat}
- B01J 37/04: Mixing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/10: in the presence of water, e.g. steam
- B01D 2255/407: Zr-Ce mixed oxides
- B01J 37/009: {Preparation by separation, e.g. by filtration, decantation, screening}
- B01J 37/0236: {Drying, e.g. preparing a suspension, adding a soluble salt and drying}
- B01J 2235/15: X-ray diffraction
- B01J 2235/30: Scanning electron microscopy; Transmission electron microscopy
- B01J 2523/00: Constitutive chemical elements of heterogeneous catalysts
- 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)

## Abstract

Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is CexZr1-x-yMyO2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol %, and y is 0-20 mol %.

## Claims

### Claim 1

A cerium-zirconium composite oxide, wherein the cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, wherein the chemical formula of the cerium-zirconium solid solution phase is CexZr1-x-yMyO2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15˜85 mol %, and y is 0˜20 mol %.

### Claim 2 (depends on 1)

The cerium-zirconium composite oxide as claimed in claim 1, wherein after the cerium-zirconium composite oxide is subjected to heat preservation at 1000° C. for 4 hours, the cerium oxide phase has a proportion of 0.5˜30 vol % in the cerium-zirconium composite oxide, preferably 3˜20 vol %.

### Claim 3 (depends on 1)

The cerium-zirconium composite oxide as claimed in claim 1, wherein the cerium-zirconium composite oxide comprises cerium oxide needle-like particles and cerium-zirconium solid solution near-spherical particles, and after being subjected to heat preservation at 1000° C. for 4 hours, the cerium oxide needle-like particles have a diameter of 7˜20 nm and a length of 50˜300 nm, the cerium-zirconium solid solution near-spherical particles have a diameter of 5˜30 nm, and the cerium oxide needle-like particles have a volume ratio of 0.5˜25% in the cerium-zirconium composite oxide.

### Claim 4 (depends on 1)

The cerium-zirconium composite oxide as claimed in claim 1, wherein after being subjected to heat preservation at 1000° C. for 4 hours, the cerium-zirconium composite oxide has a pore size of 5˜45 nm, preferably 10˜40 nm, and after being subjected to heat preservation at 1000° C. for 4 hours, the cerium-zirconium composite oxide has a specific surface area of being more than 50 m2/g.

### Claim 5 (depends on 1)

The cerium-zirconium composite oxide as claimed in claim 1, wherein after being subjected to a reduction treatment at 800° C., the cerium-zirconium composite oxide has an oxygen storage amount of being more than 600 μmol O2/g at 500° C.

### Claim 6 (depends on 1)

The cerium-zirconium composite oxide as claimed in claim 1, wherein the rare earth element other than cerium is at least one selected from the group consisting of La, Pr, Nd, Y, Sm, Eu, Tb, and Yb; the transition metal element is at least one selected from the group consisting of Cu, Mn, and Ni; and the alkaline earth metal element is at least one selected from the group consisting of Mg, Ca, Sr, and Ba.

### Claim 7 (depends on 1)

The cerium-zirconium composite oxide as claimed in claim 1, wherein the cerium oxide phase has a proportion 0.1˜30 vol % in the cerium-zirconium composite oxide.

### Claim 8

A cerium-zirconium composite oxide, wherein the cerium-zirconium composite oxide consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is CexZr1-x-yMyO2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15˜85 mol %, and y is 0˜20 mol %, and at least one of cerium-zirconium solid solution has a proportion of 0.1˜99.9 vol % in the cerium-zirconium composite oxide.

### Claim 9 (depends on 8)

The cerium-zirconium composite oxide as claimed in claim 8, wherein the cerium-zirconium composite oxide consists of two or more cerium-zirconium solid solution phases of a cubic crystal system, cell parameters of the cubic crystal system are in the range of 5.4103 Å≧a=b=c≧5.1283 Å, and there is a difference of 0.01˜0.282 Å between the cell parameters of any two of the cubic crystal systems.

### Claim 10 (depends on 8)

The cerium-zirconium composite oxide as claimed in claim 8, wherein the rare earth element other than cerium is at least one selected from the group consisting of La, Pr, Nd, Y, Sm, Eu, Tb, and Yb; the transition metal element is at least one selected from the group consisting of Cu, Mn, and Ni; and the alkaline earth metal element is at least one selected from the group consisting of Mg, Ca, Sr, and Ba.

### Claim 11 (depends on 1)

A preparation method for a cerium-zirconium composite oxide, wherein the preparation method comprises the steps of:
Step S1: preparing a feed liquid A containing a tetravalent cerium ion, a zirconium ion and a doped metal ion at a composition ratio of the cerium-zirconium solid solution phase in the cerium-zirconium complex oxide as claimed in claim 1, preparing a trivalent cerium ion solution at a proportion of the cerium oxide phase in the cerium-zirconium composite oxide, and adding a complex to the trivalent cerium ion solution to obtain a feed liquid B, wherein the doped metal ion is the M in the cerium-zirconium complex oxide, and the complex contains a coordination ion of the cerium ion;
Step S2: adding the feed liquid A, the feed liquid B and a precipitant simultaneously to a reactor to be mixed for reaction, and adjusting the pH to 7˜13 to obtain a precipitated slurry;
Step S3: aging the precipitated slurry; and
Step S4: obtaining a precipitate after the precipitated slurry being aged is subjected to solid-liquid separation, and obtaining the cerium-zirconium composite oxide after the precipitate is subjected to post-treatment.

### Claim 12 (depends on 11)

The preparation method as claimed in claim 11, wherein the complex is at least one selected from the group consisting of organic acid, an organic amine, and an aliphatic alcohol, and is preferably at least one selected from the group consisting of ethylenediaminetetraacetic acid, citric acid, acetic acid, salicylic acid, p-toluylic acid and stearyl alcohol.

### Claim 13 (depends on 11)

The preparation method as claimed in claim 11, wherein the complex has a used amount of 1˜20%, preferably 3˜10%, of the molar quantity of trivalent cerium ions in the trivalent cerium ion solution.

### Claim 14 (depends on 11)

The preparation method as claimed in claim 11, wherein the precipitant comprises at least one selected from the group consisting of magnesium carbonate solution, hydroxide of at least one element of ammonium, sodium and potassium, carbonate, and bicarbonate, preferably at least one selected from the group consisting of sodium hydroxide, ammonia and ammonium bicarbonate.

### Claim 15 (depends on 11)

The preparation method as claimed in claim 11, wherein in the Step S2, a precipitation reaction temperature is 25˜95° C. and a reaction time is 0.5˜10 hrs.

### Claim 16 (depends on 11)

The preparation method as claimed in claim 11, wherein in the Step S2, adjusting the pH to 8˜10.

### Claim 17 (depends on 11)

The preparation method as claimed in claim 11, wherein in the Step S3, an aging temperature is 50˜300° C. and an aging time is 3 hrs or more.

### Claim 18 (depends on 11)

The preparation method as claimed in claim 11, wherein the post-treatment comprises at least one step selected from the group consisting of drying, roasting and grading steps; when the post-treatment comprises the roasting, a roasting temperature is 500˜800° C., and a roasting time is 1˜10 hrs.

### Claim 19 (depends on 8)

A preparation method for a cerium-zirconium composite oxide, wherein the preparation method comprises the steps of:
Step S1: preparing each cerium-zirconium solid solution feed liquid at a composition ratio of the cerium-zirconium solid solution phase in the cerium-zirconium complex oxide as claimed in claim 8, wherein each of the cerium-zirconium solid solution feed liquid comprises a tetravalent cerium ion, a zirconium ion and a doped metal ion, wherein the doped metal ion is the M in the cerium-zirconium complex oxide;
Step S2: performing a precipitation reaction of each of the cerium-zirconium solid solution feed liquid with a precipitant one by one, and adjusting the pH to 7˜13 to obtain a precipitated slurry;
Step S3: aging the precipitated slurry; and
Step S4: obtaining a precipitate after the precipitated slurry being aged is subjected to solid-liquid separation, and obtaining the cerium-zirconium composite oxide after the precipitate is subjected to post-treatment.

### Claim 20 (depends on 1)

A preparation method for a cerium-zirconium composite oxide, wherein the preparation method comprises the steps of:
application of a catalyst prepared from the cerium-zirconium composite oxide as claimed in claim 1, wherein the catalyst is applied to vehicle exhaust gas purification, natural gas catalytic combustion, organic waste gas purification treatment and industrial waste gas denitrification treatment.