WO2022057593A1 - 一种核壳结构铈锆基复合氧化物及其制备方法 - Google Patents

一种核壳结构铈锆基复合氧化物及其制备方法 Download PDF

Info

Publication number
WO2022057593A1
WO2022057593A1 PCT/CN2021/114928 CN2021114928W WO2022057593A1 WO 2022057593 A1 WO2022057593 A1 WO 2022057593A1 CN 2021114928 W CN2021114928 W CN 2021114928W WO 2022057593 A1 WO2022057593 A1 WO 2022057593A1
Authority
WO
WIPO (PCT)
Prior art keywords
zirconium
composite oxide
cerium
yttrium
based composite
Prior art date
Application number
PCT/CN2021/114928
Other languages
English (en)
French (fr)
Inventor
张永奇
赵政
黄小卫
侯永可
崔梅生
翟志哲
冯宗玉
杨娟玉
徐旸
Original Assignee
河北雄安稀土功能材料创新中心有限公司
有研稀土新材料股份有限公司
有研稀土高技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 河北雄安稀土功能材料创新中心有限公司, 有研稀土新材料股份有限公司, 有研稀土高技术有限公司 filed Critical 河北雄安稀土功能材料创新中心有限公司
Priority to US18/027,041 priority Critical patent/US20230321631A1/en
Priority to JP2022581503A priority patent/JP2023536048A/ja
Priority to GB2219820.4A priority patent/GB2613963A/en
Publication of WO2022057593A1 publication Critical patent/WO2022057593A1/zh

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/38—Removing components of undefined structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8678—Removing components of undefined structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B01J21/066—Zirconium or hafnium; Oxides or hydroxides thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/10—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of rare earths
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/32—Manganese, technetium or rhenium
    • B01J23/34—Manganese
    • B01J35/30—
    • B01J35/396—
    • B01J35/60—
    • B01J35/613—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/009—Preparation by separation, e.g. by filtration, decantation, screening
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/03—Precipitation; Co-precipitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/03—Precipitation; Co-precipitation
    • B01J37/031—Precipitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/03—Precipitation; Co-precipitation
    • B01J37/038—Precipitation; Co-precipitation to form slurries or suspensions, e.g. a washcoat
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G25/00—Compounds of zirconium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G25/00—Compounds of zirconium
    • C01G25/006—Compounds containing, besides zirconium, two or more other elements, with the exception of oxygen or hydrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C13/00—Apparatus in which combustion takes place in the presence of catalytic material
    • F23C13/08—Apparatus in which combustion takes place in the presence of catalytic material characterised by the catalytic material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
    • F23G7/06—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases
    • F23G7/07—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases in which combustion takes place in the presence of catalytic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/206—Rare earth metals
    • B01D2255/2061—Yttrium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/206—Rare earth metals
    • B01D2255/2063—Lanthanum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/206—Rare earth metals
    • B01D2255/2066—Praseodymium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/206—Rare earth metals
    • B01D2255/2068—Neodymium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/40—Mixed oxides
    • B01D2255/407—Zr-Ce mixed oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/908—O2-storage component incorporated in the catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/92—Dimensions
    • B01D2255/9207—Specific surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/50—Solid solutions
    • C01P2002/52—Solid solutions containing elements as dopants
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/50—Solid solutions
    • C01P2002/52—Solid solutions containing elements as dopants
    • C01P2002/54—Solid solutions containing elements as dopants one element only
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G2209/00—Specific waste
    • F23G2209/14—Gaseous waste or fumes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2219/00—Treatment devices
    • F23J2219/10—Catalytic reduction devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Definitions

  • the invention relates to catalysts and the related fields of preparation, in particular to a core-shell structure cerium-zirconium-based composite oxide and a preparation method.
  • the composite oxide can be used in the fields of vehicle exhaust purification, industrial waste gas treatment, catalytic combustion and the like.
  • Cerium zirconium oxygen storage material is an indispensable key promoter material in automobile exhaust purification. Especially in the emission stage of China VI, the cerium zirconium oxygen storage material is required to have a sufficiently large specific surface area and a sufficiently high oxygen storage and release capacity in a high temperature environment.
  • the patent document CN 103191711 A proposes a method of co-precipitating zirconium salts, cerium salts and other rare earth metal salts to obtain a cerium-zirconium composite oxide with good heat resistance, the cerium-zirconium oxide at 1100 ° C. It has a specific surface area higher than 20 m 2 /g after 3 hours of calcination.
  • the improvement of heat resistance of cerium zirconium oxides by this method is still limited.
  • step-by-step precipitation is beneficial to improve the sintering resistance.
  • the patent document CN 101091914 B proposes a method of precipitation of zirconium salts and other rare earth metal salts other than cerium, and then precipitation of cerium salts.
  • the specific surface heat resistance at high temperature 1000/3h was improved.
  • the specific surface heat resistance at high temperature was still unsatisfactory after heat treatment at 1100°C for 3h (20-22m 2 /g ).
  • Patent document CN 103962120 A proposes to first contact a part of yttrium salt and other rare earth metal salts and zirconium salts other than yttrium with an alkaline substance, and then let the remaining part of the yttrium salt or the remaining part of at least one compound of yttrium and rare earth metal contact with the alkaline substance.
  • the specific surface heat resistance of cerium-zirconium composite oxides at high temperature 1000/4h
  • the sintering resistance of the layer is not strong, and the specific surface heat resistance at high temperature after heat treatment at 1100 °C for 4h is still not ideal (15-30m2/g).
  • the purpose of the present invention is to provide a core-shell structure cerium-zirconium-based composite oxide and a preparation method thereof, through which a shell layer with an outer layer enriched in yttria can be constructed, and the cerium-zirconium-based composite oxide exhibits high high heat resistance, and especially can maintain a large specific surface area even when used in a high temperature environment.
  • a core-shell structure cerium-zirconium-based composite oxide contains yttrium oxide, cerium oxide and zirconium oxide, wherein the composite oxide shell layer The yttrium oxide content in the composite oxide is higher than the overall yttrium oxide content in the composite oxide, and the core layer of the composite oxide is a cerium-zirconium-based composite oxide.
  • the yttrium oxide content in the shell layer of the composite oxide is 1.1-5.0 times the overall yttrium oxide content in the composite oxide, and the yttrium oxide content in the core layer of the composite oxide is low
  • the total yttria content in the composite oxide; the zirconia content in the shell layer of the composite oxide is 5%-40% of the total zirconia content in the composite oxide, and the core layer of the composite oxide
  • the zirconia content in the composite oxide is higher than the overall zirconia content in the composite oxide.
  • composite oxide includes the following items expressed as oxides:
  • the other oxides are a combination of one or more oxides of rare earth element oxides other than cerium and yttrium and non-rare earth element oxides other than zirconium, and in the composite oxide,
  • the content of the other oxides ranges from 0% to 18% in terms of moles, and among the other oxides, the content of oxides of rare earth elements other than cerium and yttrium ranges from 0% to 100%.
  • the content of the other oxides is 2% to 15% by molar number, and the content of the oxides of rare earth elements other than cerium and yttrium in the other oxides is 50% %-100%.
  • rare earth elements other than cerium and yttrium and non-rare earth elements other than zirconium are lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium , one or more combinations of lutetium, scandium, hafnium, aluminum, barium, manganese, and copper.
  • the rare earth elements other than cerium and yttrium and the non-rare earth elements other than zirconium are one or more combinations of lanthanum, praseodymium, neodymium, europium, aluminum, and manganese.
  • the content of yttrium oxide in the shell layer accounts for 1.5%-65% of the total element content of the shell layer, which is at least higher than the content of yttrium oxide in the overall composite oxide.
  • the rare earth element oxides other than cerium and yttrium and the non-rare earth element oxides other than zirconium in the shell layer account for 0%-15% of the total element content of the shell layer on a molar basis.
  • the composite oxide has:
  • the specific surface area is greater than 60m 2 /g after heat treatment at 1000°C for 4 hours;
  • the specific surface area was greater than 50 m 2 /g after heat treatment at 1100° C. for 4 hours.
  • the static oxygen storage capacity is greater than or equal to 600 ⁇ mol O 2 /g.
  • the static oxygen storage capacity is greater than or equal to 500 ⁇ mol O 2 /g.
  • a preparation method of a core-shell structure cerium-zirconium-based composite oxide is provided, and the preparation method is a step-by-step precipitation method, comprising the following steps:
  • the sediment slurry A or B is subjected to aging treatment.
  • the aqueous solution of rare earth salt is one or a combination of one or more of rare earth nitrate solution, chloride salt solution, sulfate solution and acetate solution.
  • the aqueous solution of zirconium salt is one or a combination of one or more of zirconium oxynitrate solution, zirconyl sulfate solution, zirconium oxychloride solution, and zirconium acetate salt.
  • the alkaline substance is one or more combinations of sodium hydroxide, ammonium hydroxide, potassium hydroxide, urea, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate.
  • the molar ratio of complexing agent ions to zirconium ions in the aqueous solution of the rare earth salt is 0.2-3.0, and the complexing agent ions are sulfate anions.
  • the molar ratio of the complexing agent ion to the zirconium ion is 0.5-2.5.
  • the modifier comprises anionic surfactants, nonionic surfactants, polyethylene glycol, carboxylic acids and salts thereof, and carboxymethylated fatty alcohol ethoxylate type surfactants. one or more.
  • a catalyst system comprising the cerium-zirconium-based composite oxide provided in the first aspect of the present invention, or the catalyst system provided by the second aspect of the present invention.
  • the cerium-zirconium-based composite oxide prepared by the preparation method, and one or more of alumina, transition metal, precious metal, and carrier.
  • a catalyst using the catalyst system as provided in the third aspect of the present invention is provided.
  • the cerium-zirconium-based composite oxide as provided in the first aspect of the present invention, the catalyst system as provided in the third aspect of the present invention, or the first aspect of the present invention as described above.
  • the present invention provides a core-shell structure cerium-zirconium-based composite oxide and a preparation method thereof, a catalyst system using the cerium-zirconium-based composite oxide, a catalyst using the catalyst system for exhaust gas purification, And the application of the catalyst system or catalyst in automobile exhaust gas purification, industrial exhaust gas treatment or catalytic combustion.
  • the invention prepares the core-shell structure cerium-zirconium-based composite oxide oxygen storage material by a step-by-step precipitation method.
  • yttrium and a part of zirconium are deposited on the surface of the cerium-zirconium, and the post-precipitation of yttrium is to make the yttrium ion (Y 3+ ) in the grain boundary Segregation on the surface, thereby reducing the surface energy of the lattice, pinning the surface of the grain boundary, making the migration of the grain boundary surface difficult, controlling the grain growth, and inhibiting the high-temperature sintering phenomenon of the solid solution, thereby improving the The thermal stability of solid solution, a part of zirconium is precipitated to enhance thermal stability; on the other hand, yttrium ions (Y 3+ , ) has a smaller ionic radius and charge, which is more conducive to reducing the formation of oxygen vacancies and improving the oxygen storage and release performance, so as to meet the oxygen storage requirements of different gasoline vehicle TWC catalysts for oxygen storage materials.
  • Fig. 1 is the schematic flow chart of the preparation method of the core-shell structure cerium-zirconium-based composite oxide of the present invention
  • the present invention uses the methods shown below to measure various physical properties:
  • the specific surface area was measured using a specific surface and pore size analyzer (Quadrasorb SI-KR/4MP) according to the BET method.
  • the samples were pretreated by vacuum degassing at a temperature of 280°C for 1 hour.
  • the sample tubes were immersed in high-purity liquid nitrogen (-196°C) for adsorption tests, and the desorption tests were performed at room temperature (25°C).
  • the static BET method was used for the measurement, and the specific surface area was calculated by BET theory at points in the range of P/P 0 of 0.05-0.3.
  • Oxygen storage was determined using a chemisorber (ChemBET Pulsar TPR/TPD) according to the oxygen pulse method. More specifically, first purge with He and raise the temperature to 150°C, continue to raise the temperature to 800°C and then reduce with 10% H 2 /Ar for 1 hour, reduce the temperature of the reactor to 500°C in a He gas stream, and reduce the residual temperature to 500°C. H 2 was purged clean, then pulsed into high-purity O 2 at 500 °C, and the total oxygen storage was calculated by counting the peak area of consumed O 2 .
  • chemisorber ChemBET Pulsar TPR/TPD
  • the overall component content is measured by ICP (Inductively Coupled Plasma Emission Spectrometer).
  • ICP Inductively Coupled Plasma Emission Spectrometer
  • the surface element content was measured by XPS, the excitation source was X-ray, and the X-ray was used to act on the surface of the sample to generate photoelectrons.
  • the photoelectron spectrum is obtained by analyzing the energy distribution of photoelectrons.
  • the element content on the surface of the material was further analyzed by the shape, position and intensity of the photoelectron spectrum peaks.
  • the first embodiment of the present invention provides a core-shell structure cerium-zirconium-based composite oxide, the composite oxide includes yttrium oxide, cerium oxide and zirconium oxide, wherein, yttrium oxide in the shell layer of the composite oxide The content is higher than the content of yttrium oxide in the overall composite oxide, and the core layer of the composite oxide is a cerium-zirconium-based composite oxide.
  • the yttrium oxide content in the shell layer of the composite oxide is 1.1-5.0 times the yttrium oxide content in the overall composite oxide, and the yttrium oxide content in the core layer is lower than the overall composite oxide content
  • the yttria content in the composite oxide; the zirconia content in the shell layer of the composite oxide is 5%-40% of the overall zirconia content, and the zirconia content in the core layer is higher than the overall zirconia content in the composite oxide. content.
  • oxide grains have a radius of 2-30 nm, and according to some embodiments, the oxide shell may have a thickness of 1-3 nm.
  • the composite oxide comprises the following, expressed as oxides: 10%-60% by molar cerium oxide; 20%-70% by molar zirconia; 1 %-20% yttrium oxide; and 0%-20% by moles of other oxides.
  • the composite oxide can be represented by the following general oxide formula: (CeO 2 ) x (ZrO 2 ) y( Y 2 O 3 ) z (MO m ) n , where 0.1 ⁇ x ⁇ 0.6, 0.2 ⁇ y ⁇ 0.7, 0.01 ⁇ z ⁇ 0.2, M is a combination of one or more of rare earth elements except cerium and yttrium and non-rare earth metal elements except zirconium, 0 ⁇ n ⁇ 0.2, m can be based on the M element. Select to confirm.
  • the other oxides are a combination of one or more oxides of rare earth element oxides other than cerium and yttrium and oxides of non-rare earth metal elements other than zirconium, and in the composite oxide, mol
  • the content of the other oxides is 0%-18%
  • the content of oxides of rare earth elements other than cerium and yttrium is 0%-100%.
  • the content of the other oxides is 2%-15% by molar number
  • the oxides of rare earth elements other than cerium and yttrium The content is 50%-100%.
  • rare earth elements other than cerium and yttrium and non-rare earth metal elements other than zirconium are lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium , scandium, hafnium, aluminum, barium, manganese, copper, one or more combinations.
  • the rare earth elements other than cerium and yttrium and the non-rare earth metal elements other than zirconium may be one or one of lanthanum, praseodymium, neodymium, europium, aluminum, and manganese combination of the above.
  • the content of yttrium oxide in the shell layer accounts for 1.5%-65% of the whole of the shell layer, which is at least higher than the content of yttrium oxide in the whole of the composite oxide, except cerium and cerium in the shell layer.
  • the content of rare earth element oxides other than yttrium and non-rare earth element oxides other than zirconium accounts for 0%-15% of the total shell layer.
  • the composite oxide has: a specific surface area greater than 60 m 2 /g after heat treatment at 1000° C. for 4 hours; and a specific surface area greater than 50 m 2 /g after heat treatment at 1100° C. for 4 hours.
  • the oxygen storage capacity is greater than or equal to 600 ⁇ mol O 2 /g.
  • the oxygen storage capacity is greater than or equal to 500 ⁇ mol O 2 /g.
  • the second embodiment of the present invention provides a preparation method of a core-shell structure cerium-zirconium-based composite oxide, the preparation method is a step-by-step precipitation method, and a schematic flow diagram of the method is shown in FIG. 1 .
  • Mixed salt solution P represents the stoichiometric amount of 80-100% cerium salt, 60-99% zirconium salt and optionally at least one rare earth salt other than cerium and yttrium salts or other than zirconium salts required to formulate the final product
  • the aqueous solution of the non-rare earth metal salt, the mixed salt solution Q represents the aqueous solution of yttrium salt, the remaining proportion of zirconium salt and cerium salt.
  • the preparation method comprises the following steps:
  • cerium salt 60-99% zirconium salt, and optionally at least one rare earth salt other than cerium and yttrium salts or non-rare earth metal salts other than zirconium salts in the stoichiometric amounts required to formulate the final product
  • concentration of the aqueous solution is 0.1-5 mol/L, preferably 0.2-2.0 mol/L.
  • a mixed aqueous solution of the prepared zirconium salt, cerium salt, and optionally at least one aqueous solution of a rare earth salt other than cerium salt and yttrium salt or an aqueous solution of a non-rare earth metal salt other than zirconium salt is brought into contact with an alkaline substance and stirred Precipitation reaction with the first step, after filtration, washing and slurrying, post-treatment is carried out.
  • the post-treatment includes one or two steps of aging or crystallization to obtain a precipitate slurry A containing at least cerium and zirconium, and the slurry A
  • the concentration is 40-60%, preferably 45-55%.
  • yttrium salt the remaining proportion of zirconium salt and cerium salt and ammonium hydroxide to carry out the second step precipitation reaction, after filtering, washing and dispersing, the post-treatment is carried out, and the post-treatment includes aging or crystallization.
  • a precipitate slurry B containing at least zirconium, cerium and yttrium is obtained, and the concentration of the slurry B is 40-70%, preferably 45-60%.
  • the slurry B is heated and a modifier is added thereto, and after filtration, a cerium-zirconium-based composite precipitate C is obtained, and after optional drying, calcination and pulverization, the cerium-zirconium-based composite oxide is obtained.
  • the composite oxide is prepared by a step-by-step precipitation method, and a shell structure with outer layers of yttrium oxide and zirconia can be constructed.
  • Upper segregation thereby reducing the surface energy of the crystal lattice, pinning the surface of the grain boundary, making the migration of the surface of the grain boundary difficult, controlling the grain growth, inhibiting the high-temperature sintering phenomenon of the solid solution, thereby improving the solid solution.
  • thermal stability Part of zirconium is precipitated to promote thermal stability; on the other hand, yttrium ions (Y 3+ , ) has a smaller ionic radius and charge, which is more conducive to lattice oxygen diffusion to improve oxygen storage and release performance.
  • the aqueous solution of the rare earth salt is one or a combination of more than one rare earth nitrate, chloride, sulfate, and acetate.
  • the aqueous solution of zirconium salt is one or a combination of more than one of zirconium oxynitrate solution, zirconium oxychloride solution, and zirconium acetate salt.
  • the aqueous solution of the rare earth salt may contain 0.2 to 3 moles of complexing agent ions, preferably sulfate anions (SO 4 2 ⁇ ), per mole of zirconium element.
  • the complexing agent ion to zirconium ion molar ratio ranges from 0.5 to 2.5, and the sulfate anion (SO 4 2 ⁇ ) can be provided by adding sulfuric acid or sulfate salt to an aqueous solution of rare earth salt.
  • the alkaline substance may be one or a combination of more than one of sodium hydroxide, ammonium hydroxide, potassium hydroxide, urea, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate.
  • the amount of the basic species in the precipitation reaction can be used in stoichiometric excess to provide optimal precipitation of all cations.
  • a sufficient amount is such that the pH of the solution is not lower than 8, and a preferred amount is such that the pH is between 8 and 12.
  • the precipitation reaction is usually carried out at a temperature comprised between 5°C and 70°C, this temperature being preferably in the range of 15°C and 60°C.
  • the stirring rate used is between 50-500 rpm and the time is usually between 1 hour and 3 hours.
  • the modifier comprises one of anionic surfactants, nonionic surfactants, polyethylene glycol, carboxylic acids and salts thereof, and carboxymethylated fatty alcohol ethoxylate type surfactants or several.
  • the calcination condition is that the obtained cerium-zirconium-based composite precipitate C is calcined at 600°C-950°C for more than 1 hour, preferably at 650°C-900°C for more than 3 hours.
  • the heat-aging treatment it is usually carried out at a temperature comprised between 25°C and 90°C, and the temperature is preferably within a range of 30°C and 80°C.
  • it is usually carried out at a temperature comprised between 40°C and 200°C, this temperature being preferably in the range of 60°C and 180°C.
  • the stirring rate used is between 50-500 rpm and the time is usually between 1 hour and 5 hours.
  • an oxidizing agent such as an aqueous hydrogen peroxide solution, may also be added during the aging treatment step.
  • the third embodiment of the present invention provides a catalyst system, the catalyst system includes the cerium-zirconium-based composite oxide provided in the above-mentioned first embodiment, or the preparation method provided in the above-mentioned second embodiment is adopted The prepared cerium-zirconium-based composite oxide, and one or more of alumina, transition metal, noble metal and carrier.
  • the fourth embodiment of the present invention provides a catalyst, which uses the catalyst system provided in the third embodiment above for exhaust gas purification.
  • the fifth embodiment of the present invention provides the cerium-zirconium-based composite oxide as provided in the above-mentioned first embodiment, the catalyst system provided in the above-mentioned third embodiment, or the catalyst system provided in the above-mentioned fourth embodiment in vehicle exhaust gas Applications in purification, industrial waste gas treatment or catalytic combustion.
  • This comparative example relates to the preparation of composite oxides based on cerium, zirconium, yttrium and lanthanum in corresponding proportions of 40%, 50%, 5%, 5% by mole fraction of oxides.
  • the brief preparation process is as follows: pre-configuring a mixed feed solution containing cerium chloride, zirconium oxychloride, yttrium chloride and lanthanum chloride.
  • the mixed liquid is added to the stoichiometric ratio of sodium hydroxide for precipitation, and the precipitate is filtered and washed.
  • the obtained filter cake is slurried and then added with polyethylene glycol and heated, and filtered after stirring.
  • the specific preparation process is as follows: pre-configured containing 101.24 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 126.55 mL of ZrOCl 2 with a concentration of 1.5 mol/L, 25.31 mL of YCl 3 with a concentration of 1.5 mol/L, and 25.31 mL of a concentration of 1.5 mol /L LaCl 3 and 83.39 mL of a mixed solution with a concentration of 2.1 mol/L H 2 SO 4 , the mixed solution was added to 536.31 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • the washed precipitate was slurried and heated to 55°C for 2 hours. After filtering and washing, polyethylene glycol was added, and the mixture was placed in an autoclave and treated at 120° C. for 6 hours. The suspension was filtered and dried, then calcined in a muffle furnace at 850°C for 4 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This comparative example relates to the preparation of composite oxides based on cerium, zirconium, yttrium, lanthanum and aluminium in corresponding proportions of 40%, 40%, 5%, 7.5% and 7.5% in terms of oxide mole fraction.
  • a brief preparation process is as follows: pre-configuring a mixed feed solution containing cerium chloride, zirconium oxychloride, yttrium chloride, lanthanum chloride and aluminum chloride.
  • the mixed liquid is added to the stoichiometric ratio of sodium hydroxide for precipitation, and the precipitate is filtered and washed.
  • cetyltrimethylammonium bromide (CTAB) was added thereto, heated, and filtered after stirring.
  • the specific preparation process is as follows: pre-configured containing 99.05 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 99.06 mL of ZrOCl 2 with a concentration of 1.5 mol/L, 24.76 mL of YCl 3 with a concentration of 1.5 mol/L, and 37.15 mL of a concentration of 1.5 mol /L LaCl 3 , 37.15 concentration of 1.5mol/L AlCl 3 and 211.50 mL of mixed feed solution of 2.1 mol/L H 2 SO 4 , the mixed feed solution was added to 550.38 mL of 2.69 mol/L NaOH solution for precipitation .
  • CTAB was added and placed in an autoclave, and treated at 150° C. for 2 hours.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 950°C for 3 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium at 10%, 70%, 20% by mole fraction of oxides.
  • the brief preparation process is as follows: two kinds of salt solutions are pre-configured, the first is the mixed solution S1 containing 90% proportion of zirconium oxychloride and 90% proportion of cerium chloride, the second is yttrium chloride and the remaining proportion of oxygen Zirconium chloride and cerium chloride feed solution S2.
  • the first mixed feed solution is added to a stoichiometric ratio of sodium hydroxide to carry out the first step of precipitation.
  • the second feed liquid yttrium chloride, zirconium oxychloride, cerium chloride and sodium hydroxide to carry out the second step precipitation, the precipitate is filtered and washed, the obtained filter cake is added oleic acid and heated after beating, Filter after stirring.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 24.22 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 169.55 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 104.56 mL of a concentration of 2.1 mol/L.
  • LH 2 SO 4 solution the second salt solution consists of 107.64 mL of YCl 3 with a concentration of 1.5 mol/L, 2.69 mL of a CeCl 3 solution with a concentration of 1.5 mol/L and 18.83 mL of a ZrOCl 2 solution with a concentration of 1.5 mol/L solution composition.
  • the first salt solution was added to 640.79 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced into the washed precipitate slurry and a stoichiometric amount of NaOH was added so that yttrium, cerium and zirconium ions were deposited on the surface.
  • heat to 55°C for 2 hours.
  • oleic acid was added and placed in an autoclave, and treated at 120° C. for 2 hours.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 850°C for 4 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and lanthanum at 20%, 59%, 3% and 18% by oxide mole fraction.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 37.09 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 129.93 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 83.45 mL of a concentration of 1.5 mol/L.
  • the second salt solution consists of 13.90 mL of 1.5 mol/L YCl 3 , 9.27 mL of 1.5 mol/L CeCl 3 solution and 6.83mL of ZrOCl 2 solution with a concentration of 1.5mol/L.
  • the first salt solution was added to 526.95 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced into the washed precipitate slurry and a stoichiometric amount of NaOH was added so that yttrium, cerium and zirconium ions were deposited on the surface.
  • hexanoic acid was added, and it was placed in an autoclave and treated at 150° C. for 2 hours.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 800°C for 3 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and lanthanum at 40%, 50%, 5% and 5% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 91.11 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 120.22 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 25.31 mL of a concentration of 1.5 mol/L.
  • the second salt solution consists of 25.31 mL of 1.5 mol/L YCl 3 , 10.12 mL of 1.5 mol/L CeCl 3 solution and 6.32mL of ZrOCl 2 solution with a concentration of 1.5mol/L.
  • the first salt solution was added to 536.31 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced into the washed precipitate slurry and a stoichiometric amount of NaOH was added so that yttrium, cerium and zirconium ions were deposited on the surface.
  • heat to 55°C for 2 hours.
  • polyethylene glycol was added, and the mixture was placed in an autoclave and treated at 120° C. for 6 hours.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 850°C for 4 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • the XRD patterns of the C 0.40 Z 0.50 L 0.5 Y 0.5 fresh and aged (1000°C ⁇ 4h and 1100°C ⁇ 4h) samples prepared by step-by-step precipitation in Example 3 are shown in Figure 2, from which the composite oxide can be found It has a tetragonal stable crystal structure after fresh and aging, and no phase separation occurs at high temperature, and the phase structure remains uniform.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and lanthanum at 50%, 30%, 10% and 10% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are prepared in advance.
  • the first salt solution consists of 101.01 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 63.97 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 44.89 mL of a concentration of 1.5 mol/L.
  • the second salt solution consists of 44.89 mL of 1.5 mol/L Y(NO 3 ) 3 and 11.22 mL of 1.5 mol/L It is composed of Ce(NO 3 ) 4 solution and 3.36 mL of ZrO(NO 3 ) 2 solution with a concentration of 1.5 mol/L.
  • the first salt solution was added to 488.18 mL of a 2.69 mol/L NaOH solution for precipitation, the precipitate was filtered and washed, and the slurry was heated to 60° C. and kept for 3 hours.
  • polyethylene glycol was added and placed in an autoclave, treated at 98°C for 1.5 hours, then a second mixed salt solution was introduced into the washed precipitate slurry and a stoichiometric amount of NH 4 OH was added so that the yttrium Ions, cerium ions and zirconium ions are deposited on the surface.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 800°C for 6 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and lanthanum at 60%, 20%, 18% and 2% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are prepared in advance.
  • the first salt solution consists of 137.08mL of CeCl 3 solution with a concentration of 1.5mol/L, 45.94mL of ZrOCl 2 with a concentration of 1.5mol/L, and 9.28mL of a concentration of 1.5mol/L.
  • the second salt solution consists of 82.24 mL of 1.5 mol/L Y(NO 3 ) 3 and 0.46 mL of 1.5 mol/L ZrO(NO 3 ) 2 solution composition.
  • the first salt solution was added to 484.12 mL of a 2.69 mol/L NaOH solution for precipitation, the precipitate was filtered and washed, and the slurry was heated to 70° C. and kept for 3 hours.
  • oleic acid was added and placed in an autoclave for 6 hours at 150°C, then a second mixed salt solution was introduced into the washed precipitate slurry and a stoichiometric amount of NH 4 OH was added so that yttrium ions and Zirconium ions are deposited on the surface.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 900°C for 3 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and praseodymium at 40%, 40%, 1% and 19% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 40.70 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 48.33 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 145.00 mL of a concentration of 1.5 mol/L.
  • the second salt solution consists of 2.54 mL of 1.5 mol/L Y(NO 3 ) 3 and 10.17 mL of 1.5 mol/L It is composed of Ce(NH 4 ) 2 (NO 3 ) 6 solution and 2.54 mL of ZrO(NO 3 ) 2 solution with a concentration of 1.5 mol/L.
  • the first salt solution was added to 445.43 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • Caproic acid was then added and placed in an autoclave for 5 hours at 110°C, then a second mixed salt solution was introduced into the washed precipitate slurry and a stoichiometric amount of NH4OH was added so that yttrium ions, cerium ions and Zirconium ions are deposited on the surface.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 850°C for 3 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and praseodymium at 40%, 40%, 15% and 5% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 41.60 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 46.23 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 131.76 mL of a concentration of 1.5 mol/L.
  • the second salt solution consists of 34.67 mL of 1.5 mol/L YCl 3 , 4.62 mL of 1.5 mol/L CeCl 3 solution and 2.31mL of ZrOCl 2 solution with a concentration of 1.5mol/L.
  • the first salt solution was added to 458.83 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced into the washed precipitate slurry and a stoichiometric amount of NaOH was added so that yttrium, cerium and zirconium ions were deposited on the surface.
  • heat to 55°C for 2 hours.
  • oleic acid was added and heated to 98°C for 1 hour.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 850°C for 4 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and praseodymium at 40%, 40%, 18% and 2% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 89.28 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 53.56 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 26.78 mL of a concentration of 1.5 mol/L.
  • L of PrCl 3 and 158.77 mL of 2.1 mol/L H 2 SO 4 solution the second salt solution consists of 80.35 mL of 1.5 mol/L YCl 3 solution and 35.71 mL of 1.5 mol/L ZrOCl 2 solution solution composition.
  • the first salt solution was added to 527.71 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced to the washed precipitate slurry and a stoichiometric amount of NaOH was added over 15 minutes to allow yttrium and zirconium ions to deposit on the surface.
  • After precipitation it was heated to 80°C for 4 hours.
  • polyethylene glycol was added and placed in an autoclave, heated to 120° C. for 6 hours. The suspension was filtered and dried, then calcined in a muffle furnace at 800°C for 5 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and neodymium at 40%, 40%, 10% and 10% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 82.58mL of CeCl 3 solution with a concentration of 1.5mol/L, 91.76mL of ZrOCl 2 with a concentration of 1.5mol/L, and 45.88mL of a concentration of 1.5mol/L.
  • the second salt solution consists of 45.88 mL of 1.5 mol/L YCl 3 , 9.17 mL of 1.5 mol/L CeCl 3 solution and 4.58mL of ZrOCl 2 solution with a concentration of 1.5mol/L.
  • the first salt solution was added to 496.32 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced to the washed precipitate slurry and a stoichiometric amount of NaOH was added within 15 minutes to allow yttrium, cerium and zirconium ions to deposit on the surface.
  • hexanoic acid was added, and the mixture was placed in an autoclave and heated to 150° C. for 6 hours.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 700°C for 6 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium and aluminum at 30%, 40%, 10% and 20% by mole fraction of oxides.
  • the specific preparation process is as follows: two kinds of salt solutions are prepared in advance.
  • the first salt solution consists of 75.05mL of CeCl 3 solution with a concentration of 1.5mol/L, 105.63mL of ZrOCl 2 with a concentration of 1.5mol/L, and 111.19mL of a concentration of 1.5mol/L.
  • the second salt solution consists of 55.59 mL of 1.5 mol/L YCl 3 , 8.33 mL of 1.5 mol/L CeCl 3 solution and 5.55mL of ZrOCl 2 solution with a concentration of 1.5mol/L.
  • the first salt solution was added to 652.56 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced to the washed precipitate slurry and a stoichiometric amount of NaOH was added within 15 minutes to allow yttrium, cerium and zirconium ions to deposit on the surface.
  • After precipitation it was heated to 60°C for 3 hours.
  • lauric acid was added, and the resultant was placed in an autoclave, heated to 180° C., and treated for 6 hours.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 750°C for 5 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium, lanthanum and aluminum at 40%, 40%, 5%, 7.5% and 7.5% by oxide mole fraction.
  • the specific preparation process is as follows: two kinds of salt solutions are pre-configured.
  • the first salt solution consists of 89.15mL of CeCl 3 solution with a concentration of 1.5mol/L, 94.11mL of ZrOCl 2 with a concentration of 1.5mol/L, and 37.15mL of a concentration of 1.5mol/L.
  • the second salt solution consists of 24.76 mL of 1.5 mol/L YCl 3 , 9.90 It consists of 1.5 mol/L CeCl 3 solution and 4.95 mL 1.5 mol/L ZrOCl 2 solution.
  • the first salt solution was added to 535.83 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced to the washed precipitate slurry and a stoichiometric amount of NaOH was added within 15 minutes to allow yttrium, cerium and zirconium ions to deposit on the surface.
  • CTAB was added and placed in an autoclave, and treated at 150° C. for 2 hours.
  • the suspension was filtered and dried, then calcined in a muffle furnace at 950°C for 3 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • This example relates to the preparation of composite oxides of cerium, zirconium, yttrium, lanthanum and manganese at 40%, 40%, 4% and, 15.5% and 0.5% by oxide mole fraction.
  • the specific preparation process is as follows: two kinds of salt solutions are prepared in advance.
  • the first salt solution consists of 71.72 mL of CeCl 3 solution with a concentration of 1.5 mol/L, 80.69 mL of ZrOCl 2 with a concentration of 1.5 mol/L, and 69.48 mL of a concentration of 1.5 mol/L.
  • the second salt solution consists of 17.93 mL of 1.5 mol/L YCl 3 , 17.93 It consists of 1.5 mol/L CeCl 3 solution and 8.96 mL 1.5 mol/L ZrOCl 2 solution.
  • the first salt solution was added to 499.60 mL of a 2.69 mol/L NaOH solution for precipitation, and the precipitate was filtered and washed.
  • a second mixed salt solution was then introduced to the washed precipitate slurry and a stoichiometric amount of NaOH was added within 15 minutes to allow yttrium, cerium and zirconium ions to deposit on the surface. After precipitation it was heated to 60°C for 1 hour. After filtering and washing, polyethylene glycol was added, and the mixture was placed in an autoclave and heated to 120° C. for 6 hours. The suspension was filtered and dried, then calcined in a muffle furnace at 860°C for 4 hours, taken out, ground, and the composite oxide was calcined at 1000°C and 1100°C for 4 hours to obtain the product.
  • the oxide content (molar percentage) of each composition in the above comparative examples and examples is shown in Table 1 below, and the specific surface area and oxygen storage performance data of each composition are shown in Table 2.
  • the proportions of Y 2 O 3 , ZrO 2 , CeO 2 and MO x (oxides of rare earth elements other than cerium and yttrium and oxides of non-rare earth elements other than zirconium) in each composition in the shell surface and overall elements are as follows: shown in Table 3.
  • Table 3 The ratio (molar percentage) of Y2O3, ZrO2, CeO2 and MOx to shell elements and total elements in each composition (fresh sample) of comparative examples and examples
  • the comparative examples and examples involved in the present invention not only include cerium-zirconium-based composite oxides with different compositions, such as high cerium, high zirconium, and middle cerium zirconium, etc., but also include cerium-zirconium-based composite oxides with different distributions of ternary, quaternary, and pentavalent.
  • the base composite oxide basically covers the range and types of the element composition in the claims.
  • the cerium-zirconium-based composite oxide prepared by the step-by-step precipitation method proposed in this patent has a high thermal stability. and better oxygen storage performance.
  • the Ce 0.40 Zr 0.50 Y 0.05 La 0.05 composite oxide prepared by co-precipitation in Comparative Example 1 has a specific surface area of 31.6 m 2 /g and an oxygen storage capacity of 373 ⁇ mol O 2 /g after calcination at 1100 ° C for 4 hours.
  • Example 3 The Ce 0.40 Zr 0.50 Y 0.05 La 0.05 composite oxide prepared by step-by-step precipitation (10% Ce, 5% Zr and all Y in step 3) was calcined at 1100 °C for 4 hours, and the specific surface area increased to 57.6 m 2 /g, the oxygen storage capacity increased to 591 ⁇ mol O 2 /g.
  • Example 11 the Ce 0.40 Zr 0.40 Y 0.05 La 0.075 Al 0.075 composite oxide prepared by co-precipitation in Comparative Example 2 was calcined at 1100 °C for 4 hours, the specific surface area was 35.3 m 2 /g, and the oxygen storage capacity was 351 ⁇ mol O 2 /g
  • the Ce 0.40 Zr 0.40 Y 0.05 La 0.075 Al 0.075 composite oxide prepared by step-by-step precipitation (10% Ce, 5% Zr and all Y in the step-by-step precipitation) was calcined at 1100 ° C for 4 hours. It was increased to 53.3m 2 /g, and the oxygen storage capacity was increased to 510 ⁇ mol O 2 /g.
  • the present invention provides a core-shell structure cerium-zirconium-based composite oxide and a preparation method thereof, a catalyst system using the cerium-zirconium-based composite oxide, a catalyst using the catalyst system for exhaust gas purification, And the application of the catalyst system or catalyst in automobile exhaust gas purification, industrial exhaust gas treatment or catalytic combustion.
  • the invention prepares the core-shell structure cerium-zirconium-based composite oxide oxygen storage material by a step-by-step precipitation method.
  • yttrium and a part of zirconium are deposited on the surface of the cerium-zirconium, and the post-precipitation of yttrium is to make the yttrium ion (Y 3+ ) in the grain boundary segregation on the surface, thereby reducing the surface energy of the crystal lattice, pinning the surface of the grain boundary, making the migration of the surface of the grain boundary difficult, controlling the grain growth, and inhibiting the high temperature of the cerium-zirconium-based composite oxide.
  • yttrium ions (Y 3+ , ) has a smaller ionic radius and charge, which is more conducive to reducing the formation of oxygen vacancies and can improve the oxygen storage and release performance to meet the requirements of different catalysts for the use of oxygen storage materials for oxygen storage.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Environmental & Geological Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Biomedical Technology (AREA)
  • General Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Combustion & Propulsion (AREA)
  • Inorganic Chemistry (AREA)
  • Toxicology (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Catalysts (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)

Abstract

本发明涉及一种核壳结构铈锆基复合氧化物及其制备方法。本发明通过分步沉淀法制备具有核壳结构的铈锆基复合氧化物储氧材料，一方面后沉钇是为了让钇离子（Y3+）在晶界表面上偏聚，抑制了铈锆基复合氧化物的高温烧结现象，从而改善铈锆基复合氧化物的热稳定性，后沉一部分锆是为了增强热稳定性；另一方面是钇离子具有更小的离子半径（0.90Å）和电荷量，更有利于降低氧空位形成能，提高储放氧性能，以满足机动车尾气净化、工业废气处理或催化燃烧等催化剂的使用要求。

Description

一种核壳结构铈锆基复合氧化物及其制备方法 技术领域
本发明涉及催化剂及其制备相关领域，尤其涉及一种核壳结构铈锆基复合氧化物及制备方法，所述复合氧化物可用于机动车尾气净化，工业废气处理和催化燃烧等领域。
背景技术
近年来大气污染备受关注，随着我国乃至世界汽车保有量的逐年增加，汽车尾气污染已成为城市大气污染的首要污染源，环境问题日益严峻。铈锆储氧材料是汽车尾气净化中不可或缺的关键助催化材料。尤其是国六排放阶段，要求铈锆储氧材料在高温环境下需要具有足够大的比表面积和足够高的储放氧能力。
为了解决这些问题，专利文献CN 103191711 A提出了将锆盐，铈盐和其它稀土金属盐共沉淀的方法来获得具有良好耐热性的铈锆复合氧化物，该铈锆氧化物在1100℃下煅烧3小时后具有高于20m 2/g的比表面积。然而，通过这种方法对铈锆氧化物的耐热性能提高仍然有限。
进一步发现通过分步沉淀有利于提高抗烧结能力，例如专利文献CN 101091914 B提出了先沉锆盐和其它除铈以外的稀土金属盐，再沉铈盐的方法，通过该方法使铈锆复合氧化物高温下(1000/3h)的比表面耐热性得以提高，然而由于铈在外层容易烧结，在1100℃下热处理3h后高温下的比表面耐热性仍不理想(20-22m 2/g)。专利文献CN 103962120 A提出了先让一部分钇盐和其它除钇以外的稀土金属盐和锆盐与碱性物质接触，再让剩余部分钇盐或钇和稀土金属的至少一种化合物的剩余一部分与与碱性物质接触，通过该方法使铈锆复合氧化物高温下(1000/4h)的比表面耐热性得以提高，然而由于未形成稳定的核壳结构，且只有稀土金属盐在表面导致外层抗烧结性能 不强，在1100℃下热处理4h后高温下的比表面耐热性仍不理想(15-30m2/g)。
发明内容
基于现有技术的上述情况，亟待开发一种1100℃高温环境下能够保持足够的热稳定性的铈锆复合氧化物，以提高催化剂的耐久性。本发明的目的在于提供一种核壳结构铈锆基复合氧化物及其制备方法，通过该制备方法可构建外层为氧化钇富集的壳层，所述铈锆基复合氧化物展现出高的耐热性，并且特别是即使在高温环境中使用时也能够保持大的比表面积。
为达到上述目的，根据本发明的一个方面，提供了一种核壳结构铈锆基复合氧化物，所述复合氧化物含有氧化钇、氧化铈和氧化锆，其中，所述复合氧化物壳层中氧化钇含量高于所述复合氧化物中总体氧化钇的含量，所述复合氧化物的核层为铈锆基复合氧化物。
进一步的，按摩尔数计，所述复合氧化物的壳层中氧化钇含量是所述复合氧化物中总体氧化钇含量的1.1-5.0倍，所述复合氧化物的核层中氧化钇含量低于所述复合氧化物中总体氧化钇含量；所述复合氧化物的壳层中氧化锆含量是所述复合氧化物中总体氧化锆含量的5％-40％，所述复合氧化物的核层中氧化锆含量高于所述复合氧化物中总体氧化锆的含量。
进一步的，该复合氧化物包含以氧化物表示的以下项：
按摩尔数计10％-60％的氧化铈；
按摩尔数计20％-70％的氧化锆；
按摩尔数计1％-20％的氧化钇；
以及按摩尔数计0％-20％的其它氧化物。
进一步的，所述其它氧化物为除铈和钇以外的稀土元素氧化物和除锆以外的非稀土元素氧化物中的一种或一种以上氧化物的组合，在所述复合氧化物中，按摩尔数计，所述其它氧化物含量为0％-18％，在所述其它氧化物中，除铈和钇以外的稀土元素氧化物含量为0％-100％。
进一步的，在所述复合氧化物中，按摩尔数计，所述其它氧化物含量为2％ -15％，在所述其它氧化物中，除铈和钇以外的稀土元素氧化物含量为50％-100％。
进一步的，所述其它氧化物中，除铈和钇以外的稀土元素和除锆以外的非稀土元素为镧、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥、钪、铪、铝、钡、锰、铜中的一种或一种以上的组合。
进一步的，所述其它氧化物中，除铈和钇以外的稀土元素和除锆以外的非稀土元素为镧、镨、钕、铕、铝、锰中的一种或一种以上的组合。
进一步的，按摩尔数计，所述壳层中氧化钇含量占所述壳层总体元素含量的1.5％-65％，至少高于氧化钇在所述复合氧化物总体中的含量。
进一步的，按摩尔数计，所述壳层中除铈和钇以外的稀土元素氧化物和除锆以外的非稀土元素氧化物占所述壳层总体元素含量的0％-15％。
进一步的，所述复合氧化物具有：
在1000℃下热处理4小时后比表面积大于60m 2/g；
在1100℃下热处理4小时后比表面积大于50m 2/g。
进一步的，所述复合氧化物在1000℃下煅烧4小时后，静态储氧量≥600μmol O 2/g。
进一步的，所述复合氧化物在1100℃下煅烧4小时后，静态储氧量≥500μmol O 2/g。
根据本发明的第二个方面，提供了一种核壳结构铈锆基复合氧化物的制备方法，所述制备方法为分步沉淀法，包括如下步骤：
(a)第一步沉淀：将碱性物质与包含以摩尔计80-100％的铈盐、60-99％的锆盐以及任选地至少一种除铈盐和钇盐之外的稀土盐或除锆盐以外的非稀土盐的水溶液混合并进行搅拌反应，经过滤、洗涤后，加水调浆得到至少含铈和锆的沉淀物浆料A；
(b)第二步沉淀：向所述浆料A中添加钇盐、剩余部分锆盐或铈盐溶液及碱性物质进行共沉淀，经过滤、洗涤后，加水调浆得到至少含锆、铈和钇的沉淀物浆料B；
(c)将所述浆料B加入改性剂进行表面改性处理，经过滤后得到铈锆基复合沉淀物C，经600℃-950℃煅烧后得到所述铈锆基复合氧化物。
进一步的，将所述沉淀物浆料A或B进行陈化处理。
进一步的，所述稀土盐的水溶液为稀土硝酸盐溶液、氯化盐溶液、硫酸盐溶液、乙酸盐溶液中的一种或一种以上的组合。锆盐的水溶液为硝酸氧锆溶液、硫酸氧锆溶液、氧氯化锆溶液、乙酸锆盐中的一种或一种以上的组合。
进一步的，所述碱性物质为氢氧化钠、氢氧化铵、氢氧化钾、尿素、碳酸氢铵、碳酸钠、碳酸氢钠中的一种或一种以上的组合。
进一步的，所述稀土盐的水溶液中配位剂离子与锆离子摩尔比为0.2-3.0，所述配位剂离子为硫酸根阴离子。
进一步的，所述配位剂离子与锆离子摩尔比为0.5-2.5。
进一步的，所述改性剂包含阴离子表面活性剂、非离子表面活性剂、聚乙二醇、羧酸及其盐、以及羧甲基化的脂肪醇乙氧基化物类型的表面活性剂中的一种或几种。
根据本发明的第三个方面，提供了一种催化剂体系，所述催化剂体系包括上述本发明第一个方面提供的所述铈锆基复合氧化物、或采用上述本发明第二个方面提供的所述制备方法制备的铈锆基复合氧化物，及氧化铝、过渡金属、贵金属、载体中的一种或几种。
根据本发明的第四个方面，提供了一种催化器，采用如上述本发明的第三个方面提供的催化剂体系。
根据本发明的第五个方面，提供了如上述本发明的第一个方面提供的铈锆基复合氧化物、如上述本发明的第三个方面提供的催化剂体系，或如上述本发明的第四个方面提供的催化器在机动车尾气净化、工业废气处理或催化燃烧中的应用。
综上所述，本发明提供了一种核壳结构铈锆基复合氧化物及其制备方法、采用所述铈锆基复合氧化物的催化剂体系、采用所述催化剂体系进行尾气净化的催化器、以及所述催化剂体系或催化器在机动车尾气净化、工业废气处 理或催化燃烧中的应用。本发明通过分步沉淀法制备该核壳结构铈锆基复合氧化物储氧材料，一方面在铈锆表面沉积钇和一部分锆，后沉钇是为了让钇离子(Y 3+)在晶界表面上偏聚，从而使晶格表面能降低，对晶界表面起到钉扎作用，使晶界表面的迁移变得困难，晶粒长大得到控制，抑制了固溶体的高温烧结现象，从而改善固溶体的热稳定性，后沉一部分锆是为了增强热稳定性；另一方面是钇离子(Y 3+，
Figure PCTCN2021114928-appb-000001
)具有更小的离子半径和电荷量，更有利于降低氧空位形成能提高储放氧性能，以满足不同汽油车TWC催化剂对储氧材料储氧量的使用要求。
附图说明
图1是本发明核壳结构铈锆基复合氧化物的制备方法的流程示意图；
图2是本发明核壳结构铈锆基复合氧化物储氧材料的xrd衍射图。
具体实施方式
为使本发明的目的、技术方案和优点更加清楚明了，下面结合具体实施方式并参照附图，对本发明进一步详细说明。应该理解，这些描述只是示例性的，而并非要限制本发明的范围。此外，在以下说明中，省略了对公知结构和技术的描述，以避免不必要地混淆本发明的概念。
本发明使用以下所示的方法测定各种物理性能：
(1)比表面积
根据BET法，使用比表面及孔径分析仪(Quadrasorb SI-KR/4MP)测定比表面积。首先将样品在温度280℃下持续真空脱气预处理1小时，样品管浸泡在高纯液氮(-196℃)中进行吸附测试，在室温(25℃)条件下进行脱附测试。采用静态BET法进行测量，选取P/P 0为0.05-0.3范围内的点通过BET理论计算比表面积。
(2)静态储氧量(OSC)
根据氧气脉冲法，使用化学吸附仪(ChemBET Pulsar TPR/TPD)测定储氧量。更具体地，先用He吹扫并升温至150℃，继续升温至800℃后用10％ H 2/Ar还原1小时，在He气流中将反应器的温度降至500℃，并将残余的H 2吹扫干净，然后在500℃脉冲进入高纯O 2，通过统计消耗O 2峰面积计算总的储氧量。
(3)总体组分含量测试
总体组分含量采用ICP测试(电感耦合等离子发射光谱仪)，根据试样原子(或离子)被激发以后，其外层电子由激发态返回到基态时，辐射跃迁所发射的特征辐射能，于各元素所对应的波长处进行测定。
(4)表面元素含量测试
表面元素含量采用XPS测试，激发源为X射线，用X射线作用于样品表面，产生光电子。通过分析光电子的能量分布得到光电子能谱。进一步通过对光电子谱峰的形状、位置及强度来对材料表面的元素含量进行分析。
本发明的第一个实施例提供了一种核壳结构铈锆基复合氧化物，所述复合氧化物包括氧化钇、氧化铈和氧化锆，其中，所述复合氧化物的壳层中氧化钇含量高于所述复合氧化物总体中氧化钇的含量，所述复合氧化物的核层为铈锆基复合氧化物。按摩尔数计，所述复合氧化物的壳层中氧化钇含量是所述复合氧化物总体中氧化钇含量的1.1-5.0倍，所述核层中氧化钇含量低于所述复合氧化物总体中的氧化钇含量；所述复合氧化物的壳层中氧化锆含量是总体中氧化锆含量的5％-40％，所述核层中氧化锆含量高于所述复合氧化物中总体氧化锆的含量。通常来说，氧化物晶粒的半径为2-30nm，根据某些实施例，所述氧化物的壳层厚度可以为1-3nm。通过构建上述结构的铈锆基复合氧化物，使得该氧化物展现出高的耐热性，并且特别是即使在高温环境中使用时也能够保持大的比表面积。
根据某些实施例，该复合氧化物包含以氧化物表示的以下项：按摩尔数计10％-60％的氧化铈；按摩尔数计20％-70％的氧化锆；按摩尔数计1％-20％的氧化钇；以及按摩尔数计0％-20％的其它氧化物。进一步的，该复合氧化物可以采用如下氧化物通式表示：(CeO 2) x(ZrO 2) y(Y 2O 3) z(MO m) n，其中0.1≤x≤0.6，0.2≤y≤0.7，0.01≤z≤0.2，M为除铈和钇以外的稀土元素和除锆以 外的非稀土金属元素中的一种或一种以上的组合，0≤n≤0.2，m可根据M元素的选取来确定。
所述其它氧化物为除铈和钇以外的稀土元素氧化物和除锆以外的非稀土金属元素氧化物中的一种或一种以上氧化物的组合，在所述复合氧化物中，按摩尔数计，所述其它氧化物含量为0％-18％，在所述其它氧化物中，除铈和钇以外的稀土元素氧化物含量为0％-100％。根据某些实施例，在所述复合氧化物中，按摩尔数计，所述其它氧化物含量为2％-15％，在所述其它氧化物中，除铈和钇以外的稀土元素氧化物含量为50％-100％。
所述其它氧化物中，除铈和钇以外的稀土元素和除锆以外的非稀土金属元素为镧、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥、钪、铪、铝、钡、锰、铜中的一种或一种以上的组合。根据某些实施例，所述其它氧化物中，除铈和钇以外的稀土元素和除锆以外的非稀土金属元素可以为镧、镨、钕、铕、铝、锰中的一种或一种以上的组合。
按摩尔数计，所述壳层中氧化钇含量占所述壳层总体的1.5％-65％，至少高于氧化钇在所述复合氧化物总体中的含量，所述壳层中除铈和钇以外的稀土元素氧化物和除锆以外的非稀土元素氧化物含量占所述壳层总体的0％-15％。
所述复合氧化物具有：在1000℃下热处理4小时后比表面积大于60m 2/g；在1100℃下热处理4小时后比表面积大于50m 2/g。所述复合氧化物在1000℃下煅烧4小时后，储氧量≥600μmol O 2/g。所述复合氧化物在1100℃下煅烧4小时后，储氧量≥500μmol O 2/g。从而可以看出，本发明该实施例提供的复合氧化物具有较好的比表面积特性和静态储氧量。
本发明的第二个实施例提供了一种核壳结构铈锆基复合氧化物的制备方法，所述制备方法为分步沉淀法，该方法的流程示意图如图1所示，图1中，混合盐溶液P表示配置最终产物所需化学计量的80-100％铈盐、60-99％的锆盐以及任选地至少一种除铈盐和钇盐之外的稀土盐或除锆盐以外的非稀土金属盐的水溶液，混合盐溶液Q表示钇盐、剩余比例的锆盐和铈盐的水溶液。 该制备方法包括如下步骤：
配置最终产物所需化学计量的80-100％铈盐、60-99％的锆盐以及任选地至少一种除铈盐和钇盐之外的稀土盐或除锆盐以外的非稀土金属盐的水溶液，其中，所述水溶液浓度为0.1-5mol/L，优选为0.2-2.0mol/L。
将配置好的锆盐、铈盐以及任选地至少一种除铈盐和钇盐之外的稀土盐或除锆盐以外的非稀土金属盐的水溶液的混合水溶液与碱性物质接触并进行搅拌和第一步沉淀反应，经过滤洗涤浆化后进行后处理，后处理包括陈化或晶化其中的一步或两步，得到至少含铈和锆的沉淀物浆料A，所述浆料A浓度为40-60％，优选为45-55％。
向所述浆料A中添加钇盐、剩余比例的锆盐和和铈盐以及氢氧化铵进行第二步沉淀反应，经过滤洗涤分散后进行后处理，后处理包括陈化或晶化其中的一步或两步，得到至少含锆、铈和钇的沉淀物浆料B，所述浆料B浓度为40-70％，优选为45-60％。
将所述浆料B加热并向其中添加改性剂，经过滤后得到铈锆基复合沉淀物C，在任选的干燥之后，煅烧、粉碎后即得到所述铈锆基复合氧化物。
本发明的该实施例中，通过分步沉淀法制备该复合氧化物，可以构建外层为氧化钇和氧化锆的壳层结构，一方面是为了让钇离子(Y 3+)在晶界表面上偏聚，从而使晶格表面能降低，对晶界表面起到钉扎作用，使晶界表面的迁移变得困难，晶粒长大得到控制，抑制了固溶体的高温烧结现象，从而改善固溶体的热稳定性。后沉一部分锆是为了促进热稳定性；另一方面是钇离子(Y 3+，
Figure PCTCN2021114928-appb-000002
)具有更小的离子半径和电荷量，更有利于晶格氧扩散提高储放氧性能。
进一步的，所述稀土盐的水溶液为稀土硝酸盐、氯化盐、硫酸盐、乙酸盐中的一种或一种以上的组合。锆盐的水溶液为硝酸氧锆溶液、氧氯化锆溶液、乙酸锆盐中的一种或一种以上的组合。该稀土盐的水溶液可以包含每摩尔锆元素0.2摩尔到3摩尔的配位剂离子，优选的为硫酸根阴离子(SO 4 2-)。该配位剂离子与锆离子摩尔比范围为0.5-2.5，并且可以通过在稀土盐的水溶 液中添加硫酸或硫酸盐来提供所述硫酸根阴离子(SO 4 2-)。
根据某些实施例，所述碱性物质可以为氢氧化钠、氢氧化铵、氢氧化钾、尿素、碳酸氢铵、碳酸钠、碳酸氢钠中的一种或一种以上的组合。其中，在沉淀反应中所述碱性物质的量可以以化学计量过量使用，以提供所有阳离子的最佳沉淀。通常，足够量是使得溶液的pH不低于8，并且优选量是使得pH在8与12之间。沉淀反应通常在包括在5℃与70℃之间的温度下进行，此温度优选在15℃与60℃的范围内。使用的搅拌速率在50-500rpm之间，时间通常在1小时与3小时之间。所述改性剂包含阴离子表面活性剂、非离子表面活性剂、聚乙二醇、羧酸及其盐、以及羧甲基化的脂肪醇乙氧基化物类型的表面活性剂中的一种或几种。
进一步的，所述煅烧条件为，将所得铈锆基复合沉淀物C在600℃-950℃下煅烧1小时以上，优选为在650℃-900℃下煅烧3小时以上。在加热陈化处理时，通常在包括在25℃与90℃之间的温度下进行，此温度优选在30℃与80℃的范围内。在其它加热后处理时，通常在包括在40℃与200℃之间的温度下进行，此温度优选在60℃与180℃的范围内。使用的搅拌速率在50-500rpm之间，时间通常在1小时与5小时之间。应指出，当铈盐中包含Ce(Ⅲ)时，也可在陈化处理步骤中添加氧化剂，例如过氧化氢水溶液。
本发明的第三实施例提供了一种催化剂体系，所述催化剂体系包括上述第一个实施例提供的所述铈锆基复合氧化物、或采用上述第二个实施例提供的所述制备方法制备的铈锆基复合氧化物，及氧化铝、过渡金属、贵金属、载体中的一种或几种。
本发明的第四实施例提供了一种催化器，采用如上述第三个实施例提供的催化剂体系进行尾气净化。
本发明的第五实施例提供了如上述第一实施例提供的铈锆基复合氧化物，如上述第三实施例提供的催化剂体系，或如上述第四实施例提供的催化器在机动车尾气净化、工业废气处理或催化燃烧中的应用。
下面通过具体的实施例对本发明进行进一步的说明。
对比实施例1：
该对比实施例涉及基于对应比例为按氧化物摩尔分数计40％、50％、5％、5％的铈、锆、钇和镧的复合氧化物的制备。
简要制备过程为：预先配置包含氯化铈、氧氯化锆、氯化钇和氯化镧的混合料液。将混合料液加入到化学计量比的氢氧化钠中沉淀，沉淀物过滤洗涤。所得滤饼经打浆后向其中加入聚乙二醇并加热，搅拌后过滤。
具体制备过程为：预先配置包含101.24mL浓度为1.5mol/L的CeCl 3溶液、126.55mL浓度为1.5mol/L的ZrOCl 2、25.31mL浓度为1.5mol/L YCl 3、25.31mL浓度为1.5mol/L LaCl 3和83.39mL浓度为2.1mol/L H 2SO 4的混合料液，将混合料液加入到536.31mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。将洗涤后的沉淀物浆化后加热至55℃并保持2小时。过滤洗涤后，添加聚乙二醇并放置于高压釜中，120℃处理6小时。过滤悬浮液并干燥，然后在马弗炉中850℃煅烧4小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
对比实施例2：
该对比实施例涉及基于对应比例为按氧化物摩尔分数计40％、40％、5％、7.5％和7.5％的铈、锆、钇、镧和铝的复合氧化物的制备。
简要制备过程为：预先配置包含氯化铈、氧氯化锆、氯化钇、氯化镧和氯化铝的混合料液。将混合料液加入到化学计量比的氢氧化钠中沉淀，沉淀物过滤洗涤。所得滤饼经打浆后向其中加入十六烷基三甲基溴化铵(CTAB)并加热，搅拌后过滤。
具体制备过程为：预先配置包含99.05mL浓度为1.5mol/L的CeCl 3溶液、99.06mL浓度为1.5mol/L的ZrOCl 2、24.76mL浓度为1.5mol/L YCl 3、37.15mL浓度为1.5mol/L LaCl 3、37.15浓度为1.5mol/L AlCl 3和211.50mL浓度为2.1mol/L H 2SO 4的混合料液，将混合料液加入到550.38mL浓度为2.69mol/L NaOH溶液中进行沉淀。过滤洗涤后，添加CTAB并放置于高压釜中，150℃处理2小时。过滤悬浮液并干燥，然后在马弗炉中950℃煅烧3小时，取出， 研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例1：
该实施例涉及按氧化物摩尔分数计10％、70％、20％的铈、锆、钇的复合氧化物的制备。
简要制备过程为：预先配置两种盐溶液，第一种为包含90％比例的氧氯化锆和90％比例的氯化铈的混合料液S1，第二种为氯化钇和剩余比例氧氯化锆和氯化铈料液S2。将第一种混合料液加入到化学计量比的氢氧化钠中进行第一步沉淀。然后向其中加入第二种料液氯化钇、氧氯化锆、氯化铈和氢氧化钠进行第二步沉淀，沉淀物过滤洗涤，所得滤饼经打浆后向其中加入油酸并加热，搅拌后过滤。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由24.22mL浓度为1.5mol/L的CeCl 3溶液、169.55mL浓度为1.5mol/L的ZrOCl 2和104.56mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由107.64mL浓度为1.5mol/L的YCl 3、2.69mL浓度为1.5mol/L的CeCl 3溶液和18.83mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到640.79mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。沉淀后加热至55℃并保持2小时。过滤洗涤后，添加油酸并放置于高压釜中，120℃处理2小时。过滤悬浮液并干燥，然后在马弗炉中850℃煅烧4小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例2
该实施例涉及按氧化物摩尔分数计20％、59％、3％和18％的铈、锆、钇和镧的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由37.09mL浓度为1.5mol/L的CeCl 3溶液、129.93mL浓度为1.5mol/L的ZrOCl 2、83.45mL浓度为1.5mol/L的LaCl 3和197.13mL浓度为2.1mol/L H 2SO 4溶液组成，第二种 盐溶液由13.90mL浓度为1.5mol/L的YCl 3、9.27mL浓度为1.5mol/L的CeCl 3溶液和6.83mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到526.95mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。过滤洗涤后，添加己酸并放置于高压釜中，150℃处理2小时。过滤悬浮液并干燥，然后在马弗炉中800℃煅烧3小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例3
该实施例涉及按氧化物摩尔分数计40％、50％、5％和5％的铈、锆、钇和镧的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由91.11mL浓度为1.5mol/L的CeCl 3溶液、120.22mL浓度为1.5mol/L的ZrOCl 2、25.31mL浓度为1.5mol/L的LaCl 3和90.39mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由25.31mL浓度为1.5mol/L的YCl 3、10.12mL浓度为1.5mol/L的CeCl 3溶液和6.32mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到536.31mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。沉淀后加热至55℃并保持2小时。过滤洗涤后，添加聚乙二醇并放置于高压釜中，120℃处理6小时。过滤悬浮液并干燥，然后在马弗炉中850℃煅烧4小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。该实施例3中分步沉淀制备的C 0.40Z 0.50L 0.5Y 0.5新鲜和老化(1000℃×4h和1100℃×4h)样品XRD图谱如图2所示，从图中可发现该复合氧化物新鲜和老化后具有四方相稳定晶体结构，且高温下未发生分相，相结构保持均一。
实施例4
该实施例涉及按氧化物摩尔分数计50％、30％、10％和10％的铈、锆、钇 和镧的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由101.01mL浓度为1.5mol/L的CeCl 3溶液、63.97mL浓度为1.5mol/L的ZrOCl 2，44.89mL浓度为1.5mol/L的LaCl 3和120.25mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由44.89mL浓度为1.5mol/L的Y(NO 3) 3、11.22mL浓度为1.5mol/L的Ce(NO 3) 4溶液和3.36mL浓度为1.5mol/L的ZrO(NO 3) 2溶液溶液组成。先将第一种盐溶液加入到488.18mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤并加热该浆料至60℃并保持3小时。过滤洗涤后，添加聚乙二醇并放置于高压釜中，98℃处理1.5小时，然后将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NH 4OH，以便钇离子、铈离子和锆离子沉积在表面。过滤悬浮液并干燥，然后在马弗炉中800℃煅烧6小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例5
该实施例涉及按氧化物摩尔分数计60％、20％、18％和2％的铈、锆、钇和镧的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由137.08mL浓度为1.5mol/L的CeCl 3溶液、45.94mL浓度为1.5mol/L的ZrOCl 2、9.28mL浓度为1.5mol/L的LaCl 3和83.14mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由82.24mL浓度为1.5mol/L的Y(NO 3) 3和0.46mL浓度为1.5mol/L的ZrO(NO 3) 2溶液溶液组成。先将第一种盐溶液加入到484.12mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤并加热该浆料至70℃并保持3小时。过滤洗涤后，添加油酸并放置于高压釜中，150℃处理6小时，然后将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NH 4OH，以便钇离子和锆离子沉积在表面。过滤悬浮液并干燥，然后在马弗炉中900℃煅烧3小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例6
该实施例涉及按氧化物摩尔分数计40％、40％、1％和19％的铈、锆、钇和镨的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由40.70mL浓度为1.5mol/L的CeCl 3溶液、48.33mL浓度为1.5mol/L的ZrOCl 2、145.00mL浓度为1.5mol/L的PrCl 3和16.34mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由2.54mL浓度为1.5mol/L的Y(NO 3) 3、10.17mL浓度为1.5mol/L的Ce(NH 4) 2(NO 3) 6溶液和2.54mL浓度为1.5mol/L的ZrO(NO 3) 2溶液溶液组成。先将第一种盐溶液加入到445.43mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后添加己酸并放置于高压釜中，110℃处理5小时，然后将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NH 4OH，以便钇离子、铈离子和锆离子沉积在表面。过滤悬浮液并干燥，然后在马弗炉中850℃煅烧3小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例7
该实施例涉及按氧化物摩尔分数计40％、40％、15％和5％的铈、锆、钇和镨的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由41.60mL浓度为1.5mol/L的CeCl 3溶液、46.23mL浓度为1.5mol/L的ZrOCl 2、131.76mL浓度为1.5mol/L的PrCl 3和83.02mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由34.67mL浓度为1.5mol/L的YCl 3、4.62mL浓度为1.5mol/L的CeCl 3溶液和2.31mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到458.83mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。沉淀后加热至55℃并保持2小时。过滤洗涤后，添加油酸并加热至98℃处理1小时。过滤悬浮液并干燥，然后在马弗炉中850℃煅烧4小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例8
该实施例涉及按氧化物摩尔分数计40％、40％、18％和2％的铈、锆、钇和镨的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由89.28mL浓度为1.5mol/L的CeCl 3溶液、53.56mL浓度为1.5mol/L的ZrOCl 2、26.78mL浓度为1.5mol/L的PrCl 3和158.77mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由80.35mL浓度为1.5mol/L的YCl 3溶液和35.71mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到527.71mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后15分钟内将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子和锆离子沉积在表面。沉淀后加热至80℃并保持4小时。过滤洗涤后，添加聚乙二醇并放置于高压釜中，加热至120℃处理6小时。过滤悬浮液并干燥，然后在马弗炉中800℃煅烧5小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例9
该实施例涉及按氧化物摩尔分数计40％、40％、10％和10％的铈、锆、钇和钕的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由82.58mL浓度为1.5mol/L的CeCl 3溶液、91.76mL浓度为1.5mol/L的ZrOCl 2、45.88mL浓度为1.5mol/L的NdCl 3和165.54mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由45.88mL浓度为1.5mol/L的YCl 3、9.17mL浓度为1.5mol/L的CeCl 3溶液和4.58mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到496.32mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后15分钟内将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。过滤洗涤后，添加己酸并放置于高压釜中，加热至150℃处理6小时。过滤悬浮液并干燥，然后在马弗炉中700℃煅烧6小时，取出，研磨，并将该复合氧化物在1000℃ 和1100℃下煅烧4小时即得产物。
实施例10
该实施例涉及按氧化物摩尔分数计30％、40％、10％和20％的铈、锆、钇和铝的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由75.05mL浓度为1.5mol/L的CeCl 3溶液、105.63mL浓度为1.5mol/L的ZrOCl 2、111.19mL浓度为1.5mol/L的AlCl 3和109.42mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由55.59mL浓度为1.5mol/L的YCl 3、8.33mL浓度为1.5mol/L的CeCl 3溶液和5.55mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到652.56mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后15分钟内将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。沉淀后加热至60℃并保持3小时。过滤洗涤后，添加月桂酸并放置于高压釜中，加热至180℃处理6小时。过滤悬浮液并干燥，然后在马弗炉中750℃煅烧5小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例11
该实施例涉及按氧化物摩尔分数计40％、40％、5％、7.5％和7.5％的铈、锆、钇、镧和铝的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由89.15mL浓度为1.5mol/L的CeCl 3溶液、94.11mL浓度为1.5mol/L的ZrOCl 2、37.15mL浓度为1.5mol/L的LaCl 3,37.15mL浓度为1.5mol/L的AlCl 3和70.76mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由24.76mL浓度为1.5mol/L的YCl 3、9.90mL浓度为1.5mol/L的CeCl 3溶液和4.95mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到535.83mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后15分钟内将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。过滤洗涤后，添加CTAB并放置于高压釜中，150℃处 理2小时。过滤悬浮液并干燥，然后在马弗炉中950℃煅烧3小时后，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
实施例12
该实施例涉及按氧化物摩尔分数计40％、40％、4％和、15.5％和0.5％的铈、锆、钇、镧和锰的复合氧化物的制备。
具体制备过程为：预先配置两种盐溶液，第一种盐溶液由71.72mL浓度为1.5mol/L的CeCl 3溶液、80.69mL浓度为1.5mol/L的ZrOCl 2、69.48mL浓度为1.5mol/L的LaCl 3、2.24mL浓度为1.5mol/L的MnCl 3和64.04mL浓度为2.1mol/L H 2SO 4溶液组成，第二种盐溶液由17.93mL浓度为1.5mol/L的YCl 3、17.93mL浓度为1.5mol/L的CeCl 3溶液和8.96mL浓度为1.5mol/L的ZrOCl 2溶液溶液组成。先将第一种盐溶液加入到499.60mL浓度为2.69mol/L NaOH溶液中进行沉淀，将沉淀物过滤洗涤。然后15分钟内将第二种混合盐溶液引入到洗涤后的沉淀物浆料并添加化学计量的NaOH，以便钇离子、铈离子和锆离子沉积在表面。沉淀后加热至60℃并保持1小时。过滤洗涤后，添加聚乙二醇并放置于高压釜中，加热至120℃处理6小时。过滤悬浮液并干燥，然后在马弗炉中860℃煅烧4小时，取出，研磨，并将该复合氧化物在1000℃和1100℃下煅烧4小时即得产物。
在以上对比实施例和实施例中各组合物的氧化物含量(摩尔百分数)如下表1所示，各组合物的比表面和储氧性能数据如表2所示。各组合物中的Y 2O 3、ZrO 2、CeO 2和MO x(除铈和钇以外的稀土元素氧化物和除锆以外的非稀土元素氧化物)占壳层表面和总体元素比例数据如表3所示。
表1 对比例和实施例中各组合物的氧化物含量(摩尔百分数)
Figure PCTCN2021114928-appb-000003
Figure PCTCN2021114928-appb-000004
表2 对比例和实施例各组合物比表面积和储氧性能数据
Figure PCTCN2021114928-appb-000005
表3 对比例和实施例各组合物(新鲜样品)中Y2O3、ZrO2、CeO2和MOx占壳层元素和总体元素比例(摩尔百分数)数据
Figure PCTCN2021114928-appb-000006
本发明涉及的对比例和实施例中既包含了高铈、高锆和中铈中锆等不同组成的铈锆基复合氧化物，又包含了三元、四元和五元不同配分的铈锆基复合氧化物，基本涵盖了权利要求中的元素组成范围和种类。通过对比例和实施例对比发现，通过分步沉淀在铈锆表面沉积钇和一部分锆确实使得1000℃×4h和1100℃×4h老化样品的比表面和储氧量得到有效提升。主要从以下两方面来体现：
对于高铈、高锆和中铈中锆等不同组成的铈锆基复合氧化物对比例和实施例比较，可以发现本专利提出的分步沉淀方法制备的铈锆基复合氧化物在热稳定性和储氧性能方面更优越。例如对比例1采用共沉淀制备的Ce 0.40Zr 0.50Y 0.05La 0.05复合氧化物在1100℃下煅烧4小时后，比表面积为31.6m 2/g，储氧量为373μmol O 2/g，实施例3中采用分步沉淀(10％Ce、5％Zr和全部的Y分步后沉)制备的Ce 0.40Zr 0.50Y 0.05La 0.05复合氧化物1100℃下煅烧 4小时后，比表面积提高到57.6m 2/g，储氧量提高到591μmol O 2/g。例如对比例2采用共沉淀制备的Ce 0.40Zr 0.40Y 0.05La 0.075Al 0.075复合氧化物在1100℃下煅烧4小时后，比表面积为35.3m 2/g，储氧量为351μmol O 2/g，实施例11中采用分步沉淀(10％Ce、5％Zr和全部的Y分步后沉)制备的Ce 0.40Zr 0.40Y 0.05La 0.075Al 0.075复合氧化物1100℃下煅烧4小时后，比表面积提高到53.3m 2/g，储氧量提高到510μmol O 2/g。因此根据以上结果可以发现采用分步沉淀方法制备的铈锆基复合氧化物老化样品的比表面和储氧量均优于传统共沉淀制备的铈锆基复合氧化物。
综上所述，本发明提供了一种核壳结构铈锆基复合氧化物及其制备方法、采用所述铈锆基复合氧化物的催化剂体系、采用所述催化剂体系进行尾气净化的催化器、以及所述催化剂体系或催化器在机动车尾气净化、工业废气处理或催化燃烧中的应用。本发明通过分步沉淀法制备该核壳结构铈锆基复合氧化物储氧材料，一方面在铈锆表面沉积钇和一部分锆，后沉钇是为了让钇离子(Y 3+)在晶界表面上偏聚，从而使晶格表面能降低，对晶界表面起到钉扎作用，使晶界表面的迁移变得困难，晶粒长大得到控制，抑制了铈锆基复合氧化物的高温烧结现象，从而改善铈锆基复合氧化物的热稳定性，后沉一部分锆是为了增强热稳定性；另一方面是钇离子(Y 3+，
Figure PCTCN2021114928-appb-000007
)具有更小的离子半径和电荷量，更有利于降低氧空位形成能提高储放氧性能，以满足不同催化剂对储氧材料储氧量的使用要求。
应当理解的是，本发明的上述具体实施方式仅仅用于示例性说明或解释本发明的原理，而不构成对本发明的限制。因此，在不偏离本发明的精神和范围的情况下所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。此外，本发明所附权利要求旨在涵盖落入所附权利要求范围和边界、或者这种范围和边界的等同形式内的全部变化和修改例。

Claims (22)

  1. 一种核壳结构铈锆基复合氧化物，其特征在于，所述复合氧化物含有氧化钇、氧化铈和氧化锆，其中，所述复合氧化物壳层中氧化钇含量高于所述复合氧化物中总体氧化钇的含量，所述复合氧化物的核层为铈锆基复合氧化物。
  2. 根据权利要求1所述的铈锆基复合氧化物，其特征在于，按摩尔数计，所述复合氧化物的壳层中氧化钇含量是所述复合氧化物中总体氧化钇含量的1.1-5.0倍，所述复合氧化物的核层中氧化钇含量低于所述复合氧化物中总体氧化钇含量；所述复合氧化物的壳层中氧化锆含量是所述复合氧化物中总体氧化锆含量的5％-40％，所述复合氧化物的核层中氧化锆含量高于所述复合氧化物中总体氧化锆的含量。
  3. 根据权利要求1或2所述的铈锆基复合氧化物，其中，该复合氧化物包含以氧化物表示的以下项：
    按摩尔数计10％-60％的氧化铈；
    按摩尔数计20％-70％的氧化锆；
    按摩尔数计1％-20％的氧化钇；
    以及按摩尔数计0％-20％的其它氧化物。
  4. 根据权利要求3所述的铈锆基复合氧化物，其特征在于，所述其它氧化物为除铈和钇以外的稀土元素氧化物和除锆以外的非稀土元素氧化物中的一种或一种以上氧化物的组合，在所述复合氧化物中，按摩尔数计，所述其它氧化物含量为0％-18％，在所述其它氧化物中，除铈和钇以外的稀土元素氧化物含量为0％-100％。
  5. 根据权利要求3所述的铈锆基复合氧化物，其特征在于，在所述复合氧化物中，按摩尔数计，所述其它氧化物含量为2％-15％，在所述其它氧化物中，除铈和钇以外的稀土元素氧化物含量为50％-100％。
  6. 根据权利要求4所述的铈锆基复合氧化物，其特征在于，所述其它氧化物中，除铈和钇以外的稀土元素和除锆以外的非稀土元素为镧、镨、 钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥、钪、铪、铝、钡、锰、铜中的一种或一种以上的组合。
  7. 根据权利要求4所述的铈锆基复合氧化物，其特征在于，所述其它氧化物中，除铈和钇以外的稀土元素和除锆以外的非稀土元素为镧、镨、钕、铕、铝、锰中的一种或一种以上的组合。
  8. 根据权利要求3所述的铈锆基复合氧化物，其特征在于，按摩尔数计，所述壳层中氧化钇含量占所述壳层总体元素含量的1.5％-65％，至少高于所述复合氧化物中总体氧化钇的含量。
  9. 根据权利要求3所述的铈锆基复合氧化物，其特征在于，按摩尔数计，所述壳层中除铈和钇以外的稀土元素氧化物和除锆以外的非稀土元素氧化物占所述壳层总体元素含量的0％-15％。
  10. 根据权利要求1或2所述的铈锆基复合氧化物，其特征在于，所述复合氧化物具有：
    在1000℃下热处理4小时后比表面积大于60m 2/g；
    在1100℃下热处理4小时后比表面积大于50m 2/g。
  11. 根据权利要求1或2所述的铈锆基复合氧化物，其特征在于，所述复合氧化物在1000℃下煅烧4小时后，静态储氧量≥600μmol O 2/g。
  12. 根据权利要求1或2所述的铈锆基复合氧化物，其特征在于，所述复合氧化物在1100℃下煅烧4小时后，静态储氧量≥500μmol O 2/g。
  13. 一种核壳结构铈锆基复合氧化物的制备方法，其特征在于，所述制备方法为分步沉淀法，包括如下步骤：
    (a)第一步沉淀：将碱性物质与包含以摩尔计80-100％的铈盐、60-99％的锆盐以及任选地至少一种除铈盐和钇盐之外的稀土盐或除锆盐以外的非稀土盐的水溶液混合并进行搅拌反应，经过滤、洗涤后，得到至少含铈和锆的沉淀物浆料A；
    (b)第二步沉淀：向所述浆料A中添加钇盐、剩余部分锆盐或铈盐溶液及碱性物质进行共沉淀，经过滤、洗涤后，得到至少含锆、铈和钇的沉 淀物浆料B；
    (c)将所述浆料B加入改性剂进行表面改性处理，经过滤后得到铈锆基复合沉淀物C，经600℃-950℃煅烧后得到所述铈锆基复合氧化物。
  14. 根据权利要求13所述的方法，其特征在于，将所述沉淀物浆料A或B进行陈化处理。
  15. 根据权利要求13所述的方法，其特征在于，所述稀土盐的水溶液为稀土硝酸盐溶液、氯化盐溶液、硫酸盐溶液、乙酸盐溶液中的一种或一种以上的组合。锆盐的水溶液为硝酸氧锆溶液、硫酸氧锆溶液、氧氯化锆溶液、乙酸锆盐中的一种或一种以上的组合。
  16. 根据权利要求13所述的方法，其特征在于，所述碱性物质为氢氧化钠、氢氧化铵、氢氧化钾、尿素、碳酸氢铵、碳酸钠、碳酸氢钠中的一种或一种以上的组合。
  17. 根据权利要求13所述的方法，其特征在于，所述稀土盐的水溶液中配位剂离子与锆离子摩尔比为0.2-3.0，所述配位剂离子为硫酸根阴离子。
  18. 根据权利要求17所述的方法，其特征在于，所述配位剂离子与锆离子摩尔比为0.5-2.5。
  19. 根据权利要求13所述的方法，其特征在于，所述改性剂包含阴离子表面活性剂、非离子表面活性剂、聚乙二醇、羧酸及其盐、以及羧甲基化的脂肪醇乙氧基化物类型的表面活性剂中的一种或几种。
  20. 一种催化剂体系，其特征在于，所述催化剂体系包括权利要求1-12中任一项所述的铈锆基复合氧化物、或采用权利要求13-19中任一项所述的制备方法制备的铈锆基复合氧化物，及氧化铝、过渡金属、贵金属、载体中的一种或几种。
  21. 一种催化器，其特征在于，含有如权利要求20所述的催化剂体系。
  22. 如权利要求1-3中任一项所述铈锆基复合氧化物，或权利要求20所述的催化剂体系，或权利要求21所述的催化器在机动车尾气净化、工业废气处理或催化燃烧中的应用。
PCT/CN2021/114928 2020-09-17 2021-08-27 一种核壳结构铈锆基复合氧化物及其制备方法 WO2022057593A1 (zh)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US18/027,041 US20230321631A1 (en) 2020-09-17 2021-08-27 Cerium-zirconium-based composite oxide with core-shell structure and preparation method thereof
JP2022581503A JP2023536048A (ja) 2020-09-17 2021-08-27 コアシェル構造のセリウム－ジルコニウム系複合酸化物及びその調製方法
GB2219820.4A GB2613963A (en) 2020-09-17 2021-08-27 Cerium zirconium based composite oxide with core-shell structure and preparation method therefor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202010982980.5A CN111939894A (zh) 2020-09-17 2020-09-17 一种核壳结构铈锆基复合氧化物及其制备方法
CN202010982980.5 2020-09-17

Publications (1)

Publication Number Publication Date
WO2022057593A1 true WO2022057593A1 (zh) 2022-03-24

Family

ID=73356319

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2021/114928 WO2022057593A1 (zh) 2020-09-17 2021-08-27 一种核壳结构铈锆基复合氧化物及其制备方法

Country Status (5)

Country Link
US (1) US20230321631A1 (zh)
JP (1) JP2023536048A (zh)
CN (1) CN111939894A (zh)
GB (1) GB2613963A (zh)
WO (1) WO2022057593A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115636691A (zh) * 2022-11-01 2023-01-24 陕西科技大学 一种球状包覆MoSi2@Y2O3核壳结构微胶囊粉体及其制备方法和应用

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111939894A (zh) * 2020-09-17 2020-11-17 河北雄安稀土功能材料创新中心有限公司 一种核壳结构铈锆基复合氧化物及其制备方法
CN116618037A (zh) * 2022-02-14 2023-08-22 有研稀土新材料股份有限公司 一种晶界和表面掺杂的铈锆复合氧化物及其制备方法和应用
CN116618040A (zh) * 2022-02-14 2023-08-22 有研稀土高技术有限公司 一种晶界和表面掺杂的稀土锰锆复合化合物及其制备方法和应用
CN116618046A (zh) * 2022-02-14 2023-08-22 有研稀土高技术有限公司 一种晶界和表面负载贵金属催化剂及其制备方法和应用
CN116618044A (zh) * 2022-02-14 2023-08-22 有研稀土高技术有限公司 一种晶界和表面负载贵金属的催化剂及其制备方法和应用
CN115650768B (zh) * 2022-09-29 2023-06-09 包头市安德窑炉科技有限公司 利用氧化锆抛光粉废料制备的隔热辐射材料的制备方法
CN117509724A (zh) * 2023-09-28 2024-02-06 江门市科恒实业股份有限公司 一种铈锆复合氧化物及其制备方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101385969A (zh) * 2008-11-05 2009-03-18 中国海洋石油总公司 一种铈铝基复合氧化物材料的制法及用途
CN102015069A (zh) * 2008-04-23 2011-04-13 罗地亚管理公司 基于锆、铈和钇的氧化物的催化组合物及其用于处理废气的用途
CN103182302A (zh) * 2011-12-28 2013-07-03 北京有色金属研究总院 具有核壳结构的稀土锆基复合氧化物及其制备方法和应用
CN110252276A (zh) * 2019-05-21 2019-09-20 山东国瓷功能材料股份有限公司 一种抗老化的铈锆复合氧化物及其制备方法和应用
CN110252275A (zh) * 2019-05-21 2019-09-20 山东国瓷功能材料股份有限公司 一种高比表面积的铈锆复合氧化物及其制备方法和应用
CN111939894A (zh) * 2020-09-17 2020-11-17 河北雄安稀土功能材料创新中心有限公司 一种核壳结构铈锆基复合氧化物及其制备方法

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4165443B2 (ja) * 2004-04-27 2008-10-15 トヨタ自動車株式会社 金属酸化物粒子の製造方法、及び排ガス浄化触媒

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102015069A (zh) * 2008-04-23 2011-04-13 罗地亚管理公司 基于锆、铈和钇的氧化物的催化组合物及其用于处理废气的用途
CN101385969A (zh) * 2008-11-05 2009-03-18 中国海洋石油总公司 一种铈铝基复合氧化物材料的制法及用途
CN103182302A (zh) * 2011-12-28 2013-07-03 北京有色金属研究总院 具有核壳结构的稀土锆基复合氧化物及其制备方法和应用
CN110252276A (zh) * 2019-05-21 2019-09-20 山东国瓷功能材料股份有限公司 一种抗老化的铈锆复合氧化物及其制备方法和应用
CN110252275A (zh) * 2019-05-21 2019-09-20 山东国瓷功能材料股份有限公司 一种高比表面积的铈锆复合氧化物及其制备方法和应用
CN111939894A (zh) * 2020-09-17 2020-11-17 河北雄安稀土功能材料创新中心有限公司 一种核壳结构铈锆基复合氧化物及其制备方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115636691A (zh) * 2022-11-01 2023-01-24 陕西科技大学 一种球状包覆MoSi2@Y2O3核壳结构微胶囊粉体及其制备方法和应用

Also Published As

Publication number Publication date
US20230321631A1 (en) 2023-10-12
CN111939894A (zh) 2020-11-17
GB202219820D0 (en) 2023-02-15
JP2023536048A (ja) 2023-08-23
GB2613963A (en) 2023-06-21

Similar Documents

Publication Publication Date Title
WO2022057593A1 (zh) 一种核壳结构铈锆基复合氧化物及其制备方法
US10882025B2 (en) Catalyst/catalyst support compositions having high reducibility and comprising a nanometric cerium oxide deposited onto a support substrate
JP5564109B2 (ja) 特有の多孔度を有する酸化セリウムおよび酸化ジルコニウムを含む組成物、この調製方法および触媒作用におけるこの使用
WO2021043256A1 (zh) 稀土锰/铈锆基复合化合物及其制备方法和应用
WO2012088373A2 (en) Catalyst support materials with oxygen storage capacity (osc) and method of making thereof
EP2794488B1 (en) Composite oxide, method for producing the same, and catalyst for exhaust gas purification
US11242264B2 (en) Alumina-based composite oxide and production method for same
WO2022057594A1 (zh) 一种元素梯度分布的铈锆基复合氧化物及其制备方法
EP2781487B1 (en) Composite oxide
WO2013092557A1 (en) Composite oxide, method for producing the same, and catalyst for exhaust gas purification
JP2022517982A (ja) ナノ結晶サイズのセリウム－ジルコニウム－アルミニウム酸化物材料およびその製造方法
JP6325010B2 (ja) アルミナ系複合酸化物及びその製造方法
JP2022518113A (ja) ナノ結晶サイズのセリウム－ジルコニウム酸化物材料およびその製造方法
JP5690372B2 (ja) 酸化鉄−ジルコニア系複合酸化物およびその製造方法
JP4061679B2 (ja) ジルコニア微粉末及びその製造方法
JP2002219361A (ja) 排ガス浄化触媒用担体及びその製造方法と触媒
WO2020063510A1 (en) Mixed oxide with improved reducibility
JP7237048B2 (ja) 酸素貯蔵材料及びその製造方法
CN117582971A (zh) 一种含Pr的铈锆基复合氧化物及其制备方法、催化剂
US20230125091A1 (en) Zirconia-based porous body and method for manufacturing zirconia-based porous body

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21868421

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2022581503

Country of ref document: JP

Kind code of ref document: A

ENP Entry into the national phase

Ref document number: 202219820

Country of ref document: GB

Kind code of ref document: A

Free format text: PCT FILING DATE = 20210827

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21868421

Country of ref document: EP

Kind code of ref document: A1