CN110026178B - Cerium-zirconium composite oxide and preparation method and application thereof - Google Patents
Cerium-zirconium composite oxide and preparation method and application thereof Download PDFInfo
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- CN110026178B CN110026178B CN201910362189.1A CN201910362189A CN110026178B CN 110026178 B CN110026178 B CN 110026178B CN 201910362189 A CN201910362189 A CN 201910362189A CN 110026178 B CN110026178 B CN 110026178B
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- 239000002131 composite material Substances 0.000 title claims abstract description 111
- RCFVMJKOEJFGTM-UHFFFAOYSA-N cerium zirconium Chemical compound [Zr].[Ce] RCFVMJKOEJFGTM-UHFFFAOYSA-N 0.000 title claims abstract description 70
- 238000002360 preparation method Methods 0.000 title description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 68
- 239000001301 oxygen Substances 0.000 claims abstract description 68
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 68
- 229910052684 Cerium Inorganic materials 0.000 claims abstract description 55
- 238000003860 storage Methods 0.000 claims abstract description 47
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 claims abstract description 45
- 239000011148 porous material Substances 0.000 claims abstract description 44
- 238000010438 heat treatment Methods 0.000 claims abstract description 35
- 230000032683 aging Effects 0.000 claims abstract description 24
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 22
- 150000002910 rare earth metals Chemical class 0.000 claims abstract description 16
- 229910000420 cerium oxide Inorganic materials 0.000 claims abstract description 15
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910001928 zirconium oxide Inorganic materials 0.000 claims abstract description 12
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims abstract description 11
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims description 33
- 238000000034 method Methods 0.000 claims description 27
- 230000009467 reduction Effects 0.000 claims description 21
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 18
- 230000001590 oxidative effect Effects 0.000 claims description 14
- 238000001354 calcination Methods 0.000 claims description 13
- 238000001027 hydrothermal synthesis Methods 0.000 claims description 12
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 claims description 11
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 claims description 11
- 229910052726 zirconium Inorganic materials 0.000 claims description 11
- MMKQUGHLEMYQSG-UHFFFAOYSA-N oxygen(2-);praseodymium(3+) Chemical compound [O-2].[O-2].[O-2].[Pr+3].[Pr+3] MMKQUGHLEMYQSG-UHFFFAOYSA-N 0.000 claims description 10
- 229910003447 praseodymium oxide Inorganic materials 0.000 claims description 10
- RUDFQVOCFDJEEF-UHFFFAOYSA-N yttrium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Y+3].[Y+3] RUDFQVOCFDJEEF-UHFFFAOYSA-N 0.000 claims description 10
- 239000003054 catalyst Substances 0.000 claims description 9
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 238000003756 stirring Methods 0.000 claims description 7
- 229910002651 NO3 Inorganic materials 0.000 claims description 6
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 6
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 6
- 229910052739 hydrogen Inorganic materials 0.000 claims description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 5
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 5
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 239000010936 titanium Substances 0.000 claims description 5
- 150000003839 salts Chemical class 0.000 claims description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims 1
- 229910044991 metal oxide Inorganic materials 0.000 claims 1
- 150000004706 metal oxides Chemical class 0.000 claims 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 18
- 239000000243 solution Substances 0.000 description 33
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 26
- -1 cerium ions Chemical class 0.000 description 19
- 238000006722 reduction reaction Methods 0.000 description 18
- 239000002002 slurry Substances 0.000 description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 11
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 10
- 235000011114 ammonium hydroxide Nutrition 0.000 description 10
- 239000007789 gas Substances 0.000 description 10
- 230000003647 oxidation Effects 0.000 description 10
- 238000007254 oxidation reaction Methods 0.000 description 10
- 239000000203 mixture Substances 0.000 description 9
- 239000006104 solid solution Substances 0.000 description 9
- 238000005406 washing Methods 0.000 description 8
- OERNJTNJEZOPIA-UHFFFAOYSA-N zirconium nitrate Chemical compound [Zr+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O OERNJTNJEZOPIA-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000009826 distribution Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- 239000012716 precipitator Substances 0.000 description 7
- 239000012266 salt solution Substances 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 239000008367 deionised water Substances 0.000 description 6
- 229910021641 deionized water Inorganic materials 0.000 description 6
- POULHZVOKOAJMA-UHFFFAOYSA-N dodecanoic acid Chemical compound CCCCCCCCCCCC(O)=O POULHZVOKOAJMA-UHFFFAOYSA-N 0.000 description 6
- 238000006460 hydrolysis reaction Methods 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 239000012065 filter cake Substances 0.000 description 5
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000000975 co-precipitation Methods 0.000 description 4
- FYDKNKUEBJQCCN-UHFFFAOYSA-N lanthanum(3+);trinitrate Chemical compound [La+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O FYDKNKUEBJQCCN-UHFFFAOYSA-N 0.000 description 4
- 229910017604 nitric acid Inorganic materials 0.000 description 4
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 4
- 239000004810 polytetrafluoroethylene Substances 0.000 description 4
- 239000002243 precursor Substances 0.000 description 4
- 238000003786 synthesis reaction Methods 0.000 description 4
- 239000005639 Lauric acid Substances 0.000 description 3
- 229910002637 Pr6O11 Inorganic materials 0.000 description 3
- 238000010335 hydrothermal treatment Methods 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- NGDQQLAVJWUYSF-UHFFFAOYSA-N 4-methyl-2-phenyl-1,3-thiazole-5-sulfonyl chloride Chemical compound S1C(S(Cl)(=O)=O)=C(C)N=C1C1=CC=CC=C1 NGDQQLAVJWUYSF-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 239000002440 industrial waste Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000005191 phase separation Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- YWECOPREQNXXBZ-UHFFFAOYSA-N praseodymium(3+);trinitrate Chemical compound [Pr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O YWECOPREQNXXBZ-UHFFFAOYSA-N 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000000779 smoke Substances 0.000 description 2
- 239000011232 storage material Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- ZSDSQXJSNMTJDA-UHFFFAOYSA-N trifluralin Chemical compound CCCN(CCC)C1=C([N+]([O-])=O)C=C(C(F)(F)F)C=C1[N+]([O-])=O ZSDSQXJSNMTJDA-UHFFFAOYSA-N 0.000 description 2
- DUFCMRCMPHIFTR-UHFFFAOYSA-N 5-(dimethylsulfamoyl)-2-methylfuran-3-carboxylic acid Chemical compound CN(C)S(=O)(=O)C1=CC(C(O)=O)=C(C)O1 DUFCMRCMPHIFTR-UHFFFAOYSA-N 0.000 description 1
- 150000000703 Cerium Chemical class 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- VYLVYHXQOHJDJL-UHFFFAOYSA-K cerium trichloride Chemical compound Cl[Ce](Cl)Cl VYLVYHXQOHJDJL-UHFFFAOYSA-K 0.000 description 1
- GHLITDDQOMIBFS-UHFFFAOYSA-H cerium(3+);tricarbonate Chemical compound [Ce+3].[Ce+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O GHLITDDQOMIBFS-UHFFFAOYSA-H 0.000 description 1
- OZECDDHOAMNMQI-UHFFFAOYSA-H cerium(3+);trisulfate Chemical compound [Ce+3].[Ce+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O OZECDDHOAMNMQI-UHFFFAOYSA-H 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000003837 high-temperature calcination Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 description 1
- CMOAHYOGLLEOGO-UHFFFAOYSA-N oxozirconium;dihydrochloride Chemical compound Cl.Cl.[Zr]=O CMOAHYOGLLEOGO-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000002468 redox effect Effects 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 150000003754 zirconium Chemical class 0.000 description 1
- GBNDTYKAOXLLID-UHFFFAOYSA-N zirconium(4+) ion Chemical compound [Zr+4] GBNDTYKAOXLLID-UHFFFAOYSA-N 0.000 description 1
- XJUNLJFOHNHSAR-UHFFFAOYSA-J zirconium(4+);dicarbonate Chemical compound [Zr+4].[O-]C([O-])=O.[O-]C([O-])=O XJUNLJFOHNHSAR-UHFFFAOYSA-J 0.000 description 1
- ZXAUZSQITFJWPS-UHFFFAOYSA-J zirconium(4+);disulfate Chemical compound [Zr+4].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O ZXAUZSQITFJWPS-UHFFFAOYSA-J 0.000 description 1
Classifications
-
- 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
- B01D53/46—Removing components of defined 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
- 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
-
- B01J35/613—
-
- B01J35/633—
-
- B01J35/647—
-
- 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
- B01J37/10—Heat treatment in the presence of water, e.g. steam
Abstract
The invention provides a cerium-zirconium composite oxide, which comprises cerium oxide, zirconium oxide and at least one oxide of rare earth metal elements except cerium, wherein the content of the at least one oxide of rare earth metal elements except cerium is 10-20 wt%; the composite oxide has a pore volume of 0.30-0.60ml/g and a pore volume of 58-100m after heat treatment at 950 ℃ for 4-8h2A specific surface area per g, and at least 1.00mmol [ O ]]Oxygen storage per gram. The cerium-zirconium composite oxide provided by the invention has a larger pore volume structure, shows remarkable oxygen storage capacity, and can still keep a good oxygen storage effect after high-temperature aging.
Description
Technical Field
The invention relates to the field of inorganic catalytic materials, in particular to a cerium-zirconium composite oxide and a preparation method and application thereof.
Background
With the development of industrialization, motor vehicle exhaust, industrial exhaust, chemical exhaust and the like become main sources causing urban air pollution, and CO, HC and NO are reducedXThe emission of such harmful gases has become a serious problem in today's society.
Cerium-based oxygen storage materials, such as ceria, can store oxygen in the presence of oxygen rich (lean) and release oxygen in the presence of oxygen lean (rich), thereby maintaining a relatively stable redox ratio and ensuring maximum catalytic purification effect of the catalyst. Wherein cerium ions are Ce generated in oxidizing or reducing atmosphere3+And Ce4+The oxidation-reduction reaction can store oxygen under the condition of oxygen enrichment to ensure NOXReducing while releasing oxygen under oxygen-deficient conditions, providing the oxygen needed for CO and HC oxidation. The above-described ability to adjust the Oxygen concentration is also referred to as an Oxygen Storage Capacity (OSC).
The cerium-zirconium solid solution is easy to have phase separation phenomenon in the synthesis process, because the valence change phenomenon of cerium ions is easy to occur in the synthesis process. The tetravalent cerium ion and the zirconium ion have similar Ksp and ionic radius, the precipitation rate is consistent in the precipitation process, the formed solid solution has stable structure, few defects, strong ageing resistance and good oxygen storage and release performance. However, in the actual synthesis, the tetravalent cerium ions have strong oxidizability and are easily reduced to trivalent cerium ions, so that the finally synthesized cerium-zirconium solid solution has phase separation. Therefore, it is important to ensure the stability of the tetravalent cerium ion during the synthesis process, and it can be achieved by adding an oxidizing substance. The prior art shows that the cerium-zirconium composite oxide is prepared by a coprecipitation method, and hydrogen peroxide and rare earth zirconium oxide mixed feed liquid is used in the precipitation process, so that the micro appearance, the redox property and the oxygen storage and release capacity of the cerium-zirconium composite oxide are influenced.
Publication No. CN104001492A provides a preparation process of a cerium-zirconium-based oxygen storage material, the proposal adopts a coprecipitation method, hydrogen peroxide is added before a precipitator is added, and the oxygen storage capacity of the prepared cerium-zirconium composite oxide after aging at 1000 ℃ is about 0.7mmol [ O ]/g.
The cerium-zirconium composite oxide prepared by the method has low oxygen storage capacity and is not ideal in practical application. Therefore, how to obtain the cerium-zirconium composite oxide with larger pore volume structure distribution has higher oxygen storage capacity and cerium reduction rate, thereby enhancing CO, HC and NO in the exhaust gasXThe conversion removal effect is achieved, and the cold start emission of the automobile is reduced; meanwhile, the high temperature resistance, ageing resistance and service life of the cerium-zirconium composite oxide catalyst are improved, and the problem to be solved in the waste gas purification catalyst is solved urgently.
Disclosure of Invention
In order to solve the above problems, in one aspect, the present invention provides a cerium-zirconium composite oxide comprising a cerium oxide, a zirconium oxide, and at least one oxide of a rare earth metal element other than cerium, wherein the content of the at least one oxide of a rare earth metal element other than cerium in the composite oxide is 10 to 20 wt%; the composite oxide has a pore volume of 0.30-0.60ml/g and a pore volume of 55-100m after heat treatment at 950 ℃ for 4-8h2Specific surface area per gram, ofAnd at least 1.00mmol [ O ]]Oxygen storage per gram. Preferably, the heat treatment may be calcination.
The cerium-zirconium composite oxide provided by the invention contains proper content of oxides of rare earth metal elements except cerium, and is beneficial to improving the oxygen storage performance of the cerium-zirconium composite oxide; meanwhile, the cerium oxide composite material has a larger pore volume structure and a proper specific surface area, can show higher oxygen storage amount and cerium reduction rate when storing and/or releasing oxygen, has a lower specific surface area attenuation rate after high-temperature aging, still has good oxygen storage and reduction effects, and shows more remarkable oxygen storage capacity, catalytic activity and high-temperature aging resistance activity.
Further, the complex oxide has a pore volume of 0.31 to 0.55ml/g, preferably 0.32 to 0.50ml/g, more preferably 0.33 to 0.40ml/g, after heat treatment at 950 ℃ for 4 to 8 hours.
Further, the composite oxide is subjected to heat treatment at 950 ℃ for 4-8h, and then is 58-90m2A specific surface area per gram, preferably 60 to 80m2Per g, more preferably from 60 to 70m2/g。
Further, the composite oxide has an oxygen storage amount of at least 1.10mmol [ O ]/g, preferably, at least 1.20mmol [ O ]/g after heat treatment at 950 ℃ for 4 to 8 hours.
Further, the composite oxide has a cerium reduction rate of at least 80%, preferably, at least 82%, after heat treatment at 950 ℃ for 4-8 h. Preferably, the composite oxide after heat treatment at 950 ℃ for 4-8h has a cerium reduction rate of at least 60% after aging at 1150 ℃, more preferably, at least 63%.
Further, the average pore diameter of the composite oxide after heat treatment at 950 ℃ for 4 to 8 hours is 15 to 30nm, preferably, the average pore diameter is 20 to 27nm, more preferably 20.5 to 25.7 nm.
Further, the composite oxide after heat treatment at 950 ℃ for 4-8h has a pore volume of 0.10-0.20ml/g, an average pore diameter of 20-30nm and a specific surface area of 10-25m after heat treatment at 1150 ℃ for 4-8h2/g。
Further, the at least one oxide of a rare earth metal element other than cerium is selected from one or more of lanthanum oxide, yttrium oxide and praseodymium oxide, and preferably, the at least one oxide of a rare earth metal element other than cerium includes lanthanum oxide and also includes one or more of yttrium oxide and praseodymium oxide.
Further, in the composite oxide, the cerium oxide and the zirconium oxide are provided in the form of cerium oxide and zirconium oxide, respectively; preferably, the content of the cerium oxide is 15 to 50 wt%.
Further, the composite oxide contains 20-48 wt% of cerium oxide, 40-65 wt% of zirconium oxide, 2-15 wt% of lanthanum oxide, 2-15 wt% of yttrium oxide and 2-15 wt% of praseodymium oxide; preferably, the composite oxide contains 22-45 wt% of cerium oxide, 45-61 wt% of zirconium oxide, 3-6 wt% of lanthanum oxide, 3-6 wt% of praseodymium oxide and 5-14 wt% of yttrium oxide.
In one embodiment, the ceria is present in an amount of 43 wt%, the zirconia is present in an amount of 46 wt%, the lanthana is present in an amount of 6 wt%, and the yttria is present in an amount of 5 wt%; in another embodiment, the ceria is present in an amount of 22 wt%, the zirconia is present in an amount of 61 wt%, the lanthana is present in an amount of 3 wt%, and the yttria is present in an amount of 14 wt%; in another embodiment, the ceria is present in an amount of 35 wt%, the zirconia is present in an amount of 55 wt%, the lanthana is present in an amount of 5 wt%, and the praseodymia is present in an amount of 5 wt%.
The cerium oxide, zirconium oxide, lanthanum oxide, yttrium oxide, praseodymium oxide, and CeO may be used respectively2、ZrO2、La2O3、Y2O3、Pr6O11Is provided in the form of (1).
On the other hand, the invention also provides a method for preparing the cerium-zirconium composite oxide, which specifically comprises the following steps: respectively dissolving cerium, zirconium and rare earth metal salt, adjusting the pH value to acidity, and reacting for a period of time; then adjusting the pH value to be alkaline, reacting for a period of time, and calcining at high temperature for a period of time to obtain the catalyst.
Further, the acidic pH is 1-3, the reaction temperature is 100-.
Further, the alkaline pH is 8-11, the reaction temperature is 100-.
Further, the high-temperature calcination condition is calcination at 800-1100 ℃ for 2-10h, preferably, calcination at 900-1000 ℃ for 4-8 h.
Further, in the above method, the concentration of cerium, zirconium and rare earth metal salt dissolved and mixed is 20 to 160 g/L.
Further, in the above method, the salt of cerium and zirconium is nitrate. Preferably, the raw materials are zirconium nitrate, ammonium ceric nitrate, lanthanum nitrate, yttrium nitrate and praseodymium nitrate, wherein the yttrium nitrate and the praseodymium nitrate are respectively prepared by dissolving yttrium oxide and praseodymium oxide in concentrated nitric acid.
In a preferred embodiment, the method is prepared by a hydrothermal reaction; more preferably, in the hydrothermal preparation of the cerium-zirconium composite oxide, a proper amount of 30% H may be added to a mixed salt solution of cerium, zirconium and a rare earth metal2O2Stirring and oxidizing for 5-35min, preferably adding hydrogen peroxide 1.5-3 times of molar weight of cerium, and oxidizing for 10 min.
At present, the preparation of cerium-zirconium solid solution mainly comprises coprecipitation technology and hydrothermal technology. Compared with a coprecipitation technology, the cerium-zirconium solid solution prepared by the hydrothermal technology has the advantages of uniform particles, few defects, stable structure, high crystallinity and more excellent ageing resistance. However, the performance of the solid solution prepared by the hydrothermal technology is greatly influenced by trivalent cerium ions in the solution, and the more trivalent cerium ions, the more easily the prepared solid solution is subjected to phase splitting. Therefore, it is important to reduce the concentration of the trivalent cerium ions in the solution as much as possible. The experimental result shows that the oxygen storage capacity and the cerium reduction rate of the cerium-zirconium composite oxide prepared by the hydrothermal method are obviously higher than those of the cerium-zirconium composite oxide prepared by oxidizing the hydrogen peroxide and then coprecipitating the mixture for a period of time after the hydrogen peroxide is added into the mixed salt solution of cerium, zirconium and rare earth metal for oxidation.
In one embodiment, the cerium salt may also be cerium nitrate, cerium chloride, cerium sulfate, cerium carbonate; the zirconium salt may also be zirconium carbonate, zirconium oxychloride, zirconium sulfate, zirconium acetate.
In a preferred embodiment, the hydrothermal preparation process comprises the following steps:
s1, respectively dissolving cerium, zirconium and rare earth metal salt, wherein the total concentration is 20-160 g/L;
s2, adding a proper amount of 30% H into the solution2O2Stirring and oxidizing for 5-35 min;
s3, dropwise adding an alkaline precipitator, wherein the alkaline precipitator is one or more of ammonia water, sodium hydroxide and amines, preferably mainly ammonia water, and then adjusting the pH value of the solution to 1.5-2;
s4, introducing the solution into a high-pressure reaction kettle, and carrying out high-temperature hydrolysis reaction at the temperature of 120-220 ℃ for 10-20 h;
s5, dropwise adding an alkaline precipitator into the precursor slurry obtained in the step S3 to adjust the pH value to 8-10;
s6, introducing the precursor slurry obtained in the step S4 into an autoclave, and carrying out hydrothermal reaction at the temperature of 120-220 ℃ for 6-10 h;
s7, filtering, washing, drying the filter cake for 10h, and calcining at 900-1000 ℃ for 4-8 h.
The cerium-zirconium composite oxide with appropriate pore volume can also be prepared by other preparation methods by those skilled in the art under the teaching of the present invention, and the cerium-zirconium composite oxide with appropriate pore volume defined by the present invention is not limited to be prepared by the preparation method of the present application.
For example, in one embodiment, the effect of adjusting the pore volume of the product may be achieved by adjusting the hydrothermal temperature; in another embodiment, a step of oxidizing by using hydrogen peroxide can be added, and the pore volume of the product is adjusted by adjusting the time of oxidation; in other embodiments, the concentration of the reactants in the preparation process may be adjusted to achieve the effect of adjusting the pore volume of the product.
In another aspect, the present invention also provides the use of the cerium zirconium composite oxide for storing and/or releasing oxygen.
In another aspect, the present invention also provides a method for storing and/or releasing oxygen, comprising the step of storing and/or releasing oxygen at a high temperature using the above composite oxide, the composite oxide having an oxygen storage amount of not less than 1.00mmol [ O ]/g after heat treatment at a high temperature for 4 to 8 hours, the high temperature being not less than 900 ℃. Preferably, the composite oxide may be stored and/or released with oxygen after heat treatment at 950 ℃ -1150 ℃ for 4-8 h.
The cerium-zirconium composite oxide has a larger pore volume distribution structure and a larger specific surface area, shows remarkable oxygen storage capacity, has oxygen storage capacity of not less than 1.00mmol [ O ]/g and up to 1.35mmol [ O ]/g after heat treatment for 6 hours at 950 ℃, and has cerium reduction rate of not less than 80 percent and up to 92.9 percent; the oxygen storage capacity after heat treatment for 6h at 1150 deg.C is greater than 0.90mmol [ O ]/g, up to 0.95mmol [ O ]/g, the cerium reduction rate is greater than 60%, up to 65.4%, showing more obvious oxygen storage capacity, catalytic activity and high-temperature aging resistance activity.
The invention has the beneficial effects that:
the cerium-zirconium composite oxide with a proper pore volume structure is obtained, and the remarkable oxygen storage capacity is shown; in addition, the cerium-zirconium composite oxide can still keep good oxygen storage effect after being aged at high temperature. Experiments show that the oxygen storage capacity of the cerium-zirconium composite oxide is not lower than 1.00mmol [ O ]/g after heat treatment for 6 hours at 950 ℃, and the cerium reduction rate is not lower than 80%; the oxygen storage amount after heat treatment for 6h at 1150 deg.C is greater than 0.90mmol [ O ]/g, the cerium reduction rate is greater than 60%, it shows more obvious oxygen storage capacity, catalytic activity and high-temperature ageing resistance activity, and it has great significance for the research of the purificant for treating automobile tail gas, industrial waste gas, etc. containing cerium-zirconium composite oxide.
Detailed Description
In order to more clearly explain the overall concept of the present application, the following detailed description is given by way of example. In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present application. It will be apparent, however, to one skilled in the art, that the present application may be practiced without one or more of these specific details. In other instances, well-known features of the art have not been described in order to avoid obscuring the present application.
In the following examples, raw materials for preparing cerium-zirconium composite oxides are commercially available, unless otherwise specified; wherein the container used for the hydrolysis reaction is a pressure bomb provided by special chemical equipment limited company on the smoke bench side and provided with a polytetrafluoroethylene lining with the volume specification of 10L, and the container used for the hydrothermal reaction is a titanium high-pressure reaction kettle provided by special chemical equipment limited company on the smoke bench side and provided with the volume specification of 10L; the pore volume and the pore diameter are measured by adopting a Micromeritics TriStar type II full-automatic adsorption instrument provided by American Michelle instruments; the oxygen storage capacity of the cerium-zirconium solid solution was analyzed using a chemisorption analyzer, model chemdbet-3000, available from kanta corporation.
In the following examples, the pore volume and pore size test method is as follows: firstly, heating a sample to 300 ℃ under a vacuum condition and keeping the temperature for 3 hours, removing organic matters and water in the sample, then weighing 0.15-0.30g of the sample, placing the sample in a Micromeritics TriStar type II full-automatic adsorption instrument, setting parameters, automatically completing the adsorption and desorption process of the sample to gas by the instrument, and then automatically calculating the specific surface area, the pore volume and the pore diameter by a computer. Wherein, the specific surface area is calculated according to a BET formula method, and the pore size distribution is calculated according to a BJH formula method.
The invention provides a preparation method of a cerium-zirconium composite oxide, which comprises the step of preparing by a hydrothermal method, and specifically comprises the following steps:
s1, respectively dissolving cerium, zirconium and rare earth metal salt, wherein the total concentration is 20-160 g/L;
s2, adding a proper amount of 30% H into the solution2O2Stirring and oxidizing for 5-35 min;
s3, dropwise adding an alkaline precipitator, wherein the alkaline precipitator is one or more of ammonia water, sodium hydroxide and amines, preferably mainly ammonia water, and then adjusting the pH value of the solution to 1.5-2;
s4, introducing the solution into a high-pressure reaction kettle, and carrying out high-temperature hydrolysis reaction at the temperature of 120-220 ℃ for 10-20 h;
s5, dropwise adding an alkaline precipitator into the precursor slurry obtained in the step S3 to adjust the pH value to 8-10;
s6, introducing the precursor slurry obtained in the step S4 into an autoclave, and carrying out hydrothermal reaction at the temperature of 120-220 ℃ for 6-10 h;
s7, filtering, washing, drying the filter cake for 10h, and calcining at 900-1000 ℃ for 4-8 h.
Unless otherwise specified, the following examples were prepared by the above-described method.
Example 1
Example 1 provides a cerium-zirconium composite oxide prepared by the following method:
473.5g of zirconium nitrate is taken and dissolved by 2000ml of deionized water until the solution is clear, 16.3g of yttrium oxide is taken and dissolved by 53.2g of concentrated nitric acid, then the solution is mixed with the solution, 434.4g of ammonium ceric nitrate and 84.9g of lanthanum nitrate are added, the mixture is stirred until the solution is clear, a solution A is obtained, and 30 percent H with the molar weight 1.5 times that of cerium is added into the solution A2O2Stirring and oxidizing for 10 min;
adjusting the pH of the oxidized solution A to 1.5-2 by using ammonia water under the condition of 50 ℃ water bath, fixing the volume to 6400ml, introducing the solution A into a polytetrafluoroethylene lining pressure soluble bomb, carrying out hydrothermal hydrolysis reaction at 180 ℃ for 20h, and adjusting the pH to about 9.5 by using ammonia water at normal temperature to obtain slurry B;
and transferring the slurry B into a titanium material kettle, and carrying out hydrothermal reaction at 180 ℃ for 10h under the condition that the rotating speed is 200 r/min. Filter-pressing the slurry after hydrothermal treatment, washing for 3 times by using 50L of deionized water, washing for 2 times by using 560g of lauric acid solution to obtain a final filter cake, and calcining at high temperature for removing rubber, wherein the calcining conditions are as follows: the temperature is raised to 950 ℃ by adopting a programmed heating mode, and the heating rate is 2 ℃/min. The gas flow of the furnace body is controlled at 10-20L (air)/min/kg (oxide), and the calcined material is sieved by a sieve with 200-250 meshes, thus obtaining the cerium-zirconium composite oxide.
The cerium-zirconium composite oxide obtained by the method comprises the following components: CeO (CeO)243％，ZrO246％，La2O36％，Y2O35 percent. Wherein the concentration of the oxide is 100g/L, and the total mass of the oxide is 325 g.
Example 2
Embodiment 2 provides a cerium-zirconium composite oxide, which is prepared by the following method:
550.7g of zirconium nitrate is taken and dissolved by 2000ml of deionized water until the solution is clear, 39.9g of yttrium oxide is taken and dissolved by 102.0g of concentrated nitric acid and then mixed with the solution, 194.9g of ammonium ceric nitrate and 22.3g of lanthanum nitrate are added, the mixture is stirred until the solution is clear, a solution A is obtained, and 30 percent H with the molar weight 1.5 times that of cerium is added into the solution A2O2Stirring and oxidizing for 10 min;
adjusting the pH of the oxidized solution A to 1.5-2 by using ammonia water under the condition of 50 ℃ water bath, fixing the volume to 6400ml, introducing the solution A into a polytetrafluoroethylene lining pressure soluble bomb, carrying out hydrothermal hydrolysis reaction at 180 ℃ for 20h, and adjusting the pH to about 9.5 by using ammonia water at normal temperature to obtain slurry B;
and transferring the slurry B into a titanium material kettle, and carrying out hydrothermal reaction at 180 ℃ for 10h under the condition that the rotating speed is 200 r/min. Filter-pressing the slurry after hydrothermal treatment, washing for 3 times by using 50L of deionized water, washing for 2 times by using 560g of lauric acid solution to obtain a final filter cake, and calcining at high temperature for removing rubber, wherein the calcining conditions are as follows: the temperature is raised to 950 ℃ by adopting a programmed heating mode, and the heating rate is 2 ℃/min. The gas flow of the furnace body is controlled at 10-20L (air)/min/kg (oxide), and the calcined material is sieved by a sieve with 200-250 meshes, thus obtaining the cerium-zirconium composite oxide.
The cerium-zirconium composite oxide obtained by the method comprises the following components: CeO (CeO)222％，ZrO261％，La2O33％，Y2O314 percent. Wherein the concentration of the oxide is 100g/L, and the total mass of the oxide is 285 g.
Example 3
Example 3 provides a cerium-zirconium composite oxide, which is prepared by the following method:
757.8g of zirconium nitrate is taken and dissolved by 2000ml of deionized water until the solution is clear, 24.5g of praseodymium oxide is taken and dissolved by 55.0g of concentrated nitric acid and then mixed with the solution, 473.3g of ammonium ceric nitrate and 58.3g of lanthanum nitrate are added, the mixture is stirred until the solution is clear, a solution A is obtained, and 30 percent H with the molar weight 1.5 times that of cerium is added into the solution A2O2Stirring and oxidizing for 10 min;
adjusting the pH of the oxidized solution A to 1.5-2 by using ammonia water under the condition of 50 ℃ water bath, fixing the volume to 6400ml, introducing the solution A into a polytetrafluoroethylene lining pressure soluble bomb, carrying out hydrothermal hydrolysis reaction at 180 ℃ for 20h, and adjusting the pH to about 9.5 by using ammonia water at normal temperature to obtain slurry B;
and transferring the slurry B into a titanium material kettle, and carrying out hydrothermal reaction at 180 ℃ for 10h under the condition that the rotating speed is 200 r/min. Filter-pressing the slurry after hydrothermal treatment, washing for 3 times by using 50L of deionized water, washing for 2 times by using 560g of lauric acid solution to obtain a final filter cake, and calcining at high temperature for removing rubber, wherein the calcining conditions are as follows: the temperature is raised to 950 ℃ by adopting a programmed heating mode, and the heating rate is 2 ℃/min. The gas flow of the furnace body is controlled at 10-20L (air)/min/kg (oxide), and the calcined material is sieved by a sieve with 200-250 meshes, thus obtaining the cerium-zirconium composite oxide.
The cerium-zirconium composite oxide obtained by the method comprises the following components: CeO (CeO)235％，ZrO255％，La2O35％，Pr6O115 percent. Wherein the concentration of the oxide is 100g/L, and the total mass of the oxide is 435 g.
Example 4
Cerium-zirconium composite oxide (composition: CeO) was prepared according to the preparation method of example 2222％，ZrO261％，La2O33％，Y2O314%) and the difference is that in the preparation process, hydrogen peroxide is added into a mixed salt solution of cerium, zirconium and rare earth metal, and the mixed salt solution is stirred and oxidized for 5 min.
Example 5
Cerium-zirconium composite oxide (composition: CeO) was prepared according to the preparation method of example 2222％，ZrO261％，La2O33％，Y2O314%) and the difference is that in the preparation process, hydrogen peroxide is added into a mixed salt solution of cerium, zirconium and rare earth metal, and the mixed salt solution is stirred and oxidized for 15 min.
Example 6
Cerium-zirconium composite oxide (composition: CeO) was prepared according to the preparation method of example 2222％，ZrO261％，La2O33％，Y2O314 percent) is added into the mixed salt solution of cerium, zirconium and rare earth metal and stirredStirring and oxidizing for 20 min.
Comparative example 1
Cerium-zirconium composite oxide (composition: CeO) was prepared according to the preparation method of example 1243％，ZrO246％，La2O36％，Y2O35%) and the difference is that no hydrogen peroxide is added for oxidation in the preparation process.
Comparative example 2
A cerium-zirconium composite oxide (composition: CeO) was prepared in accordance with the preparation method of example 3235％，ZrO255％，La2O35％，Pr6O115 percent) and is only added with hydrogen peroxide to oxidize for 30min in the preparation process.
Example 7 evaluation of Properties
First, pore structure distribution
The pore volume, pore diameter and specific surface area of the freshly prepared cerium-zirconium composite oxide and the high-temperature aged cerium-zirconium composite oxide were measured for each of the above examples, and the attenuation rate of the specific surface area of the cerium-zirconium composite oxide before and after aging was calculated to determine the degree of influence of the high-temperature aging on the pore structure of the catalyst. The specific results are shown in table 1, wherein the freshly prepared cerium-zirconium composite oxide was calcined at 950 ℃ for 6 hours, and the high-temperature aging was carried out by aging the catalyst at 1150 ℃ for 6 hours.
Table 1 shows the pore structure distribution in the freshly prepared and after aging at elevated temperatures
As can be seen from the data in Table 1, the cerium-zirconium composite oxide prepared by the method has a large pore structure distribution, and particularly, the newly prepared (calcined at 950 ℃ for 6 hours) examples 1 to 3 have a pore volume of 0.30 to 0.60mg/L, an average pore diameter of 15 to 30nm, and a specific surface area of 58 to 80m2/g。
Compared with comparative examples 1-2, examples 1-6 have smaller pore volumes, pore diameters and attenuation degrees of specific surface areas before and after high-temperature aging (aging at 1150 ℃ for 6 hours), which shows that the cerium-zirconium composite oxide provided by the invention is less affected by high-temperature aging than other cerium-zirconium composite oxides with pore structure distribution.
Meanwhile, comparing examples 1 to 3 with examples 4 to 6 and comparative example 2, it can be seen that the time for oxidizing with hydrogen peroxide before preparing the cerium-zirconium composite oxide by the hydrothermal method has a certain influence on the pore volume structure and the specific surface area of the cerium-zirconium composite oxide, and the optimal effect can be achieved within 10 minutes in the method compared with the most preferable oxidation time of 30 minutes in the prior art.
Second, testing oxygen storage capacity
The catalysts of each example were subjected to oxygen storage capacity tests (OSC analysis) for fresh preparation and after high-temperature aging, respectively, to evaluate the oxygen storage activity and high-temperature aging resistance of the resulting catalysts, as follows: 0.2g of the sample powder was heated to 600 ℃ and kept in high purity oxygen for 1 hour for sufficient oxidation, and the sample powder was heated from 100 ℃ to 1000 ℃ in a 5% hydrogen-argon gas flow (100sccm) at a heating rate of 10 ℃/min, and hydrogen consumed during this period was continuously measured with a quadrupole mass spectrometer to obtain a water vapor generation curve accompanied by a temperature increase, and the oxygen release amount was determined from the obtained hydrogen consumption curve and its area. And the reduction rate of cerium oxide was calculated according to the following formula:
cerium reduction rate ((OSC: mol-O)2)/0.25mol/mol-CeO2)×100％
TABLE 2 oxygen storage amount and reduction ratio of cerium ion
As can be seen from the data in table 2, the cerium-zirconium composite oxides obtained in examples have larger oxygen storage amounts and higher cerium reduction rates than comparative examples, but there is a difference between the oxygen storage capacities of the respective exemplified cerium-zirconium composite oxides.
Wherein, compared with comparative example 1, the oxygen storage amount and the cerium reduction rate of examples 1 to 3 are obviously increased, which shows that the oxygen storage effect of the cerium-zirconium composite oxide obtained by the invention is superior to that of the cerium-zirconium composite oxide prepared without adding hydrogen peroxide for oxidation. In particular, in example 2, the oxygen storage amount in the case of freshly prepared (calcined at 950 ℃ for 6 hours) was 1.35mmol/g, the cerium reduction rate was 92.9%, the oxygen storage amount after aging at 1150 ℃ for 6 hours was 0.95mmol/g, and the cerium reduction rate was 65.4%, showing remarkable oxygen storage capacity and high-temperature sintering resistance. Therefore, compared with the existing cerium-zirconium solid solution, the cerium-zirconium composite oxide provided by the invention has a more obvious oxygen storage effect, and can still maintain a better effect after high-temperature aging.
Meanwhile, as can be seen from comparison of examples 1 to 3 with examples 4 to 6 and comparative example 2, the time for oxidizing with hydrogen peroxide before the preparation of the cerium-zirconium composite oxide by the hydrothermal method also has a certain effect on the oxygen storage amount and the cerium reduction rate of the cerium-zirconium composite oxide, and the oxygen storage capacity tends to increase and then decrease. Compared with the oxidation time of 30 minutes with the best oxygen storage effect in the prior art, in the method, the oxidation time of 10 minutes can ensure that the cerium-zirconium composite oxide achieves the optimal oxygen storage effect.
In conclusion, the cerium-zirconium composite oxide provided by the invention has larger pore volume and specific surface area, shows better oxygen storage performance and high-temperature aging resistance, saves oxidation time in the preparation method, improves production efficiency in actual work, and has great significance in research on obtaining treatment purifiers of automobile exhaust, industrial waste gas and the like containing the cerium-zirconium composite oxide.
The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims (19)
1. A cerium-zirconium composite oxide comprising a cerium oxide, a zirconium oxide and an oxide of at least one rare earth metal element selected from the group consisting of cerium,
the content of the at least one oxide of a rare earth metal element other than cerium is 10 to 20 wt%;
the composite oxide has a pore volume of 0.30-0.60ml/g and a pore volume of 55-100m after heat treatment at 950 ℃ for 4-8h2A specific surface area per g, and at least 1.00mmol [ O ]]Oxygen storage per gram;
the cerium-zirconium composite oxide is prepared by a hydrothermal method: respectively dissolving zirconium, at least one salt of a rare earth metal element other than cerium, and ammonium ceric nitrate, mixing, and adding 30% H with a molar amount of 1.5-3 times of cerium2O2Stirring and oxidizing for 10min, adjusting the pH value to acidity, and reacting for 5-30h at the reaction temperature of 100-300 ℃; then adjusting the pH value to be alkaline, reacting at the temperature of 100-300 ℃ for 5-30h, and calcining at the temperature of 900-1000 ℃ to obtain the catalyst.
2. The composite oxide according to claim 1, wherein the composite oxide has a pore volume of 0.31 to 0.55ml/g after heat treatment at 950 ℃ for 4 to 8 hours.
3. The composite oxide according to claim 1, wherein the composite oxide has a pore volume of 0.32 to 0.50ml/g after heat treatment at 950 ℃ for 4 to 8 hours.
4. The composite oxide according to claim 1, wherein the composite oxide has a pore volume of 0.33 to 0.40ml/g after heat treatment at 950 ℃ for 4 to 8 hours.
5. The composite oxide according to claim 1, wherein the composite oxide has a thickness of 58 to 90m after heat treatment at 950 ℃ for 4 to 8 hours2Specific surface area in g.
6. The composite oxide according to claim 1, wherein the metal oxide is selected from the group consisting of titanium oxide, and titanium oxideAfter the composite oxide is heat-treated at 950 ℃ for 4-8h, the composite oxide has a thickness of 60-80m2Specific surface area in g.
7. The composite oxide according to claim 1, wherein the composite oxide has a thickness of 60 to 70m after heat treatment at 950 ℃ for 4 to 8 hours2Specific surface area in g.
8. The composite oxide according to claim 1, wherein the composite oxide has an oxygen storage amount of at least 1.10mmol [ O ]/g after heat treatment at 950 ℃ for 4 to 8 hours.
9. The composite oxide according to claim 1, wherein the composite oxide has an oxygen storage amount of at least 1.20mmol [ O ]/g after heat treatment at 950 ℃ for 4 to 8 hours.
10. The composite oxide according to claim 1, wherein the composite oxide has a cerium reduction rate of at least 80% after heat treatment at 950 ℃ for 4 to 8 hours.
11. The composite oxide according to claim 1, wherein the composite oxide heat-treated at 950 ℃ for 4 to 8 hours has a cerium reduction rate of at least 60% after aging at 1150 ℃.
12. The composite oxide according to claim 1, wherein the composite oxide has a cerium reduction rate of at least 82% after heat treatment at 950 ℃ for 4 to 8 hours.
13. The composite oxide according to claim 1, wherein the at least one oxide selected from rare earth elements other than cerium is selected from one or more of lanthanum oxide, yttrium oxide, and praseodymium oxide.
14. The composite oxide according to claim 1, wherein the at least one oxide of a rare earth metal element other than cerium comprises at least lanthanum oxide, and further comprises one or both of yttrium oxide and praseodymium oxide.
15. The composite oxide according to any one of claims 1 to 14, wherein the cerium oxide and the zirconium oxide are provided in the form of cerium oxide and zirconium oxide, respectively.
16. The composite oxide according to any one of claims 1 to 14, wherein the content of the cerium oxide is 15 to 50 wt%.
17. The composite oxide according to claim 13 or 14, wherein the content of ceria is 20 to 48 wt%, the content of zirconia is 40 to 65 wt%, the content of lanthana is 2 to 15 wt%, the content of yttria is 2 to 15 wt%, and the content of praseodymia is 2 to 15 wt%.
18. The composite oxide according to claim 13 or 14, wherein the composite oxide contains 22 to 45 wt% of cerium oxide, 45 to 61 wt% of zirconium oxide, 3 to 6 wt% of lanthanum oxide, 5 to 14 wt% of yttrium oxide, and 3 to 6 wt% of praseodymium oxide.
19. A method for storing and/or releasing oxygen, comprising the step of storing and/or releasing oxygen using the composite oxide according to any one of claims 1 to 18.
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| CN105983403A (en) * | 2015-02-09 | 2016-10-05 | 有研稀土新材料股份有限公司 | Cerium-zirconium composite oxide, preparation method of cerium-zirconium composite oxide and use of catalyst |
| CN108855132A (en) * | 2018-06-26 | 2018-11-23 | 中国石油大学(北京) | Multi-stage porous cerium zirconium oxide supported spinel-type palladium cobalt composite oxide catalyst |
| CN109529802A (en) * | 2018-11-12 | 2019-03-29 | 山东国瓷功能材料股份有限公司 | A kind of cerium zirconium compound oxide and its preparation method and application |
| CN109529801A (en) * | 2018-11-12 | 2019-03-29 | 山东国瓷功能材料股份有限公司 | Controllable double hole channel cerium zirconium compound oxide and its preparation method and application |
| CN109464999A (en) * | 2018-12-07 | 2019-03-15 | 昆明冶金研究院 | A kind of VOCs catalysis burning catalyst carrier modified aluminas and preparation method thereof |
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