# US 12,109,551 B2 · Rare-earth-manganese/cerium-zirconium-based composite compound, method for preparing same and use thereof

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- Number: US 12,109,551 B2
- Document ID: US12109551B2
- Status: Granted
- Kind: B2
- Application number: 17/422,691
- Filed: 2020-09-04
- Published: 2022-06-16
- Granted: 2024-10-08
- Earliest claimed: 2019-09-04
- Assignees: Grirem Advanced Materials Co., Ltd.; Rare Earth Functional Materials (Xiong'an) Innovation Center Co., Ltd.; Grirem Hi-Tech Co., Ltd.
- Applicants: Grirem Advanced Materials Co., Ltd.; Rare Earth Functional Materials (Xiong 'an) Innovation Center Co., Ltd.; Grirem Hi-Tech Co., Ltd.
- Inventors: Xiaowei Huang; Yongqi Zhang; Hongwei Li; Zhizhe Zhai; Qiang Zhong; He Zhang; Meisheng Cui; Yongke Hou; Hao Wang; Zongyu Feng
- Web page: https://patentgrep.com/patent/US12109551B2

## CPC

- B01J 23/10: of rare earths
- B01J 23/8892: {Manganese}
- B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)}
- B01J 6/001: {Calcining}
- B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof}
- B01J 23/02: of the alkali- or alkaline earth metals or beryllium
- B01J 23/34: Manganese
- B01J 35/19: {Catalysts containing parts with different compositions}
- B01J 35/397: {Egg shell like}
- B01J 35/398: {Egg yolk like}
- B01J 35/40: characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77)
- B01J 37/0236: {Drying, e.g. preparing a suspension, adding a soluble salt and drying}
- B01J 37/033: {Using Hydrolysis}
- B01J 37/035: {Precipitation on carriers}
- B01J 37/04: Mixing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/06: Washing {(B01J37/0009, B01J37/0018 take precedence)}
- B01J 37/082: {Decomposition and pyrolysis}
- F01N 3/10: by thermal or catalytic conversion of noxious components of exhaust
- B01D 2255/206: Rare earth metals
- B01D 2255/2061: Yttrium
- B01D 2255/2063: Lanthanum
- B01D 2255/2065: Cerium
- B01D 2255/2066: Praseodymium
- B01D 2255/2068: Neodymium
- B01D 2255/2073: Manganese
- B01D 2255/407: Zr-Ce mixed oxides
- B01D 2255/908: O2-storage component incorporated in the catalyst
- B01J 21/18: Carbon
- B01J 2235/15: X-ray diffraction
- B01J 2523/00: Constitutive chemical elements of heterogeneous catalysts
- F01N 2570/14: Nitrogen oxides
- Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- 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)
- F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

The present invention discloses a rare-earth-manganese/cerium-zirconium-based composite compound, a method for preparing the same, and a use thereof. The composite compound is of a core-shell structure with a general formula expressed as: A REcBaOb-(1-A)CexZr(1-x-y)MyO2-z, wherein 0.1≤A≤0.3, preferably 0.1≤A≤0.2; a shell layer has a main component of rare-earth manganese oxide with a general formula of REcMnaOb, wherein RE is a rare-earth element or a combination of more than one rare-earth elements, and B is Mn or a combination of Mn and a transition metal element, 1≤a≤8, 2≤b≤18, and 0.25≤c≤4; and a core has a main component of cerium-zirconium composite oxide with a general formula of CexZr(1-x-y)MyO2-z, wherein M is one or more non-cerium rare-earth elements, 0.1≤x≤0.9, 0≤y≤0.3, and 0.01≤z≤0.3. The composite compound enhances an oxygen storage capacity of a cerium-zirconium material through an interface effect, thereby increasing a conversion rate of a nitrogen oxide.

## Claims

### Claim 1

A rare-earth-manganese/cerium-zirconium-based composite compound,
comprising a core-shell structure, having a general formula expressed as: A REcBaOb-(1-A)CexZr(1-x-y) MyO2-z, wherein 0.1≤Δ≤0.3;
a shell layer has a main component of rare-earth manganese oxide having a general formula of REcBaOb, wherein RE is a rare-earth element or a combination of more than one rare-earth elements, B is Mn or a combination of Mn and a transition metal element, 1≤a≤8, 2<b≤18, and 0.25≤c≤4; and
a core has a main component of cerium-zirconium composite oxide having a general formula of CexZr (1-x-y) MyO2-z, wherein M is at least one selected from a group consisting of a non-cerium rare-earth element and a transition metal element, 0.1≤x≤0.9, 0≤y≤0.3, and 0.01≤z≤0.3.

### Claim 2 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein a mass of the Mn element in the shell layer is 70-98 wt % of a total mass of the Mn element in the rare-earth-manganese/cerium-zirconium-based composite compound.

### Claim 3 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein cerium in the cerium-zirconium composite oxide has composite valence states of trivalence and tetravalence, and tetravalent cerium accounts for 60-90 wt % of the total amount of cerium.

### Claim 4 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein 1≤a≤3, 2≤b≤8, and the shell layer is a compound of a mullite-type structure.

### Claim 5 (depends on 4)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 4, wherein a mass of the Mn element in the shell layer is 70-95 wt % of a total mass of the Mn element in the rare-earth-manganese/cerium-zirconium-based composite compound.

### Claim 6 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein
the rare-earth element RE in the rare-earth manganese oxide comprises one or more selected from a group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, and yttrium;
M in the cerium-zirconium composite oxide is one or more selected from a group consisting of lanthanum, praseodymium, neodymium, yttrium, samarium, europium, gadolinium, holmium, erbium, thulium, ytterbium, hafnium, aluminum, and barium.

### Claim 7 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein the shell layer further contains one or more selected from a group consisting of a hydroxide, a carbonate and a basic carbonate, with a content of 0.01-1 wt %.

### Claim 8 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein
the rare-earth manganese oxide is doped with the transition metal element which is one or more selected from a group consisting of iron, tungsten, molybdenum, nickel, cobalt, vanadium, and titanium; and
a mass of the transition metal element is 0.01%-10% of a mass of the rare-earth manganese oxide, wherein the mass of the transition metal element is based on the self-mass of the transition metal element, and the mass of the rare-earth manganese oxide is based on the mass of the rare-earth manganese oxide before the transition metal element is doped.

### Claim 9 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein an oxygen storage capacity of the rare-earth-manganese/cerium-zirconium-based composite compound is not less than 800 umol-O2/g.

### Claim 10 (depends on 1)

The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein a particle size D50 is 1-15 μm.

### Claim 11 (depends on 1)

A method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, comprising:
reacting a mixed raw material containing a divalent manganese source, a rare-earth source, and a cerium-zirconium composite oxide to obtain the rare-earth-manganese/cerium-zirconium-based composite compound.

### Claim 12 (depends on 11)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 11, wherein said reacting the mixed raw material containing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide comprises the following steps:
preparing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide according to a stoichiometric ratio of a final product; and
adding a mixed solution containing the divalent manganese source and the rare-earth source to the cerium-zirconium composite oxide for reaction, and after the reaction is completed, drying, calcining and pulverizing a resultant to obtain the rare-earth-manganese/cerium-zirconium-based composite compound.

### Claim 13 (depends on 12)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 12, wherein the reaction occurs under the following specific conditions:
the reaction occurs under stirring;
a reaction temperature is 15-45° C.; and
reaction duration is 5-20 min.

### Claim 14 (depends on 12)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 12, wherein the divalent manganese source in the mixed solution has a concentration of 2-4 mol/L, with a molar weight of the divalent manganese source based on a molar weight of a manganese element; and
the rare-earth source in the mixed solution has a concentration of 0.5-2 mol/L, with a molar weight of the rare-earth source based on a molar weight of the rare-earth element.

### Claim 15 (depends on 12)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 12, wherein the mixed solution containing the divalent manganese source and the rare-earth source has a volume accounting for 70-150% of a pore volume of the cerium zirconium composite oxide.

### Claim 16 (depends on 11)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 11, wherein said reacting the mixed raw material containing the manganese source, the rare-earth source and the cerium-zirconium composite oxide comprises the following steps:
preparing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide according to a stoichiometric ratio of a final product; and
adding a precipitant and an oxidant sequentially to a mixed slurry containing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide for reaction, and after the reaction is completed, washing, drying, calcining and pulverizing a resultant to obtain the rare-earth-manganese/cerium-zirconium-based composite compound.

### Claim 17 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the precipitant is at least one selected from a group consisting of sodium hydroxide, ammonia water, ammonium bicarbonate and potassium hydroxide.

### Claim 18 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the precipitant has an amount of substance accounting for 5-90% of a stoichiometric amount required to precipitate a manganese element and a rare-earth element in the slurry.

### Claim 19 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the precipitant is added to the mixed slurry in a form of a precipitant solution; and
the precipitant in the precipitant solution has a concentration of 0.5-5 mol/L.

### Claim 20 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the oxidant is at least one selected from a group consisting of hydrogen peroxide, oxygen, sodium persulfate, potassium persulfate and ammonium persulfate.

### Claim 21 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the oxidant has an amount of substance being 0.05-1 time an amount of substance of Mn2+ contained in the slurry.

### Claim 22 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the washing occurs under the following specific conditions:
the washing is performed by using deionized water, with a washing end-point at which a conductivity of the deionized water is less than 40 us/cm.

### Claim 23 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the mixed slurry containing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide is prepared by a method comprising the following steps:
adding the cerium-zirconium composite oxide to water to obtain a cerium-zirconium composite oxide slurry; and
mixing the mixed solution containing the divalent manganese source and the rare-earth source with the cerium-zirconium composite oxide slurry to obtain the mixed slurry.

### Claim 24 (depends on 23)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 23, wherein the cerium-zirconium composite oxide in the cerium-zirconium composite oxide slurry has a mass concentration of 10-50%.

### Claim 25 (depends on 23)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 23, wherein the divalent manganese source in the mixed solution has a concentration of 0.5-2.5 mol/L, with a molar weight of the divalent manganese source based on a molar weight of the manganese element; and
the rare-earth source in the mixed solution has a concentration of 0.5-1.5 mol/L, with a molar weight of the rare-earth source based on a molar weight of the rare-earth element.

### Claim 26 (depends on 11)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 11, wherein the divalent manganese source is a soluble metal salt of the manganese, and the soluble metal salt of the manganese is at least one selected from a group consisting of a manganese nitrate, a manganese acetate, a manganese chloride and a manganese sulfate; and
the rare-earth source is a soluble metal salt of the rare earth, and the soluble metal salt of the rare earth is at least one selected from a group consisting of a rare-earth nitrate, a rare-earth acetate, a rare-earth chloride and a rare-earth sulfate.

### Claim 27 (depends on 16)

The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16, wherein the calcining occurs under the following conditions:
a calcining temperature is 500-900° C.; and
calcining duration is 1-6 h.

### Claim 28 (depends on 1)

A catalyst comprising the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1, wherein the catalyst is used for catalytic oxidation of NO in motor vehicle exhaust.