CN114870860A - Natural gas vehicle tail gas purification catalyst and preparation method thereof - Google Patents
Natural gas vehicle tail gas purification catalyst and preparation method thereof Download PDFInfo
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- CN114870860A CN114870860A CN202210391348.2A CN202210391348A CN114870860A CN 114870860 A CN114870860 A CN 114870860A CN 202210391348 A CN202210391348 A CN 202210391348A CN 114870860 A CN114870860 A CN 114870860A
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- 239000003054 catalyst Substances 0.000 title claims abstract description 141
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- 239000007789 gas Substances 0.000 title claims abstract description 28
- 239000003345 natural gas Substances 0.000 title claims abstract description 24
- 238000000746 purification Methods 0.000 title claims abstract description 18
- 238000002360 preparation method Methods 0.000 title abstract description 26
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- 239000011248 coating agent Substances 0.000 claims abstract description 125
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- RCFVMJKOEJFGTM-UHFFFAOYSA-N cerium zirconium Chemical compound [Zr].[Ce] RCFVMJKOEJFGTM-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 14
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- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 30
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- 238000005470 impregnation Methods 0.000 claims description 8
- 229910052748 manganese Inorganic materials 0.000 claims description 8
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims description 7
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims description 6
- 229910052777 Praseodymium Inorganic materials 0.000 claims description 6
- 235000011114 ammonium hydroxide Nutrition 0.000 claims description 6
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- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 claims description 4
- 229910052783 alkali metal Inorganic materials 0.000 claims description 4
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- 229910052700 potassium Inorganic materials 0.000 claims description 2
- 238000004537 pulping Methods 0.000 claims description 2
- 229910052701 rubidium Inorganic materials 0.000 claims description 2
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- 229910052723 transition metal Inorganic materials 0.000 claims description 2
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- 239000000446 fuel Substances 0.000 abstract description 16
- 229910052760 oxygen Inorganic materials 0.000 abstract description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 12
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- 239000001301 oxygen Substances 0.000 abstract description 12
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- 230000000694 effects Effects 0.000 abstract description 9
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- 238000006243 chemical reaction Methods 0.000 description 22
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 15
- 229910052878 cordierite Inorganic materials 0.000 description 14
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical group [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 14
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 13
- 239000010948 rhodium Substances 0.000 description 13
- 229910052746 lanthanum Inorganic materials 0.000 description 12
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 8
- 229910052726 zirconium Inorganic materials 0.000 description 8
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 7
- 150000002823 nitrates Chemical class 0.000 description 7
- 229910021645 metal ion Inorganic materials 0.000 description 6
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 5
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 4
- NWAHZABTSDUXMJ-UHFFFAOYSA-N platinum(2+);dinitrate Chemical compound [Pt+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O NWAHZABTSDUXMJ-UHFFFAOYSA-N 0.000 description 4
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 4
- 239000010970 precious metal Substances 0.000 description 4
- 239000007864 aqueous solution Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 229910052727 yttrium Inorganic materials 0.000 description 3
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 229910021193 La 2 O 3 Inorganic materials 0.000 description 2
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 2
- 229910017493 Nd 2 O 3 Inorganic materials 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- GPNDARIEYHPYAY-UHFFFAOYSA-N palladium(ii) nitrate Chemical compound [Pd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O GPNDARIEYHPYAY-UHFFFAOYSA-N 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- MKYBYDHXWVHEJW-UHFFFAOYSA-N N-[1-oxo-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propan-2-yl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(C(C)NC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 MKYBYDHXWVHEJW-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- AZJLMWQBMKNUKB-UHFFFAOYSA-N [Zr].[La] Chemical compound [Zr].[La] AZJLMWQBMKNUKB-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
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- 238000002485 combustion reaction Methods 0.000 description 1
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- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
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- 230000035484 reaction time Effects 0.000 description 1
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 1
- 238000003980 solgel method Methods 0.000 description 1
- 238000000629 steam reforming Methods 0.000 description 1
- 239000011232 storage material Substances 0.000 description 1
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Classifications
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- 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
- B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
- B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
- B01J23/8933—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/8986—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals also combined with metals, or metal oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with manganese, technetium or rhenium
-
- 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
- B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
- B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
-
- B01J35/615—
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- 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
- B01J37/0201—Impregnation
-
- 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
- B01J37/0215—Coating
- B01J37/0228—Coating in several steps
-
- 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
- B01J37/024—Multiple impregnation or coating
- B01J37/0244—Coatings comprising several layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/90—Physical characteristics of catalysts
- B01D2255/902—Multilayered catalyst
- B01D2255/9025—Three layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/90—Physical characteristics of catalysts
- B01D2255/903—Multi-zoned catalysts
- B01D2255/9035—Three zones
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/01—Engine exhaust gases
- B01D2258/018—Natural gas engines
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- 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
-
- 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
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
The invention discloses a natural gas vehicle tail gas purification catalyst and a preparation method thereof, wherein the catalyst comprises a catalyst carrier, and a first coating, a second coating and a third coating which are coated in a segmented and/or layered mode, wherein the first coating is La x A y Mn z B 1‑z O 3 The perovskite type composite oxide is loaded on the specific surfaceAt 150m 2 Per gram of alumina or first modified alumina; the second coating is formed by loading noble metal Pt and/or Pd on the cerium-zirconium composite oxide and/or the second modified alumina; the third coating is made of noble metal Pt, Rh or Pd, Rh loaded on the cerium zirconium composite oxide and/or the third modified alumina; the second coating is arranged at the front end or the lower layer of the third coating. The first coating of the catalyst can fully exert the oxygen storage and release function and the catalytic function of the perovskite, convert part of pollutants and simultaneously adjust the fluctuation of the air-fuel ratio, and after the first coating is matched with an oxidation type catalyst and a reduction type catalyst for use, the activity of the catalyst can be improved, the emission of pollutants is reduced, the consumption of noble metals is reduced, and the cost is saved.
Description
Technical Field
The invention relates to the technical field of motor vehicle tail gas purification, in particular to a natural gas vehicle tail gas purification catalyst and a preparation method thereof.
Background
Natural gas vehicles are increasingly being used as "clean fuels". The emission standard of the natural gas vehicle at the present stage of China is implemented to the sixth stage of China, compared with the fifth stage of China, the emission limit value of each pollutant is further reduced, the endurance mileage is increased, and a by-product NH is regulated 3 The emission value of (c). Because the exhaust temperature of the natural gas vehicle is much lower than that of the gasoline vehicle, the exhaust temperature is CH 4 The C-H bond in the molecule has high energy and is difficult to break, in addition, the triple effect window is slightly rich and narrow, the fluctuation of the air-fuel ratio is large, and the higher content of the C-H bond in the molecule is generally required to be usedThe noble metal can achieve effective conversion of the three pollutants. In the prior art, precious metals are used as active components to prepare catalysts, but in recent years, the prices of precious metals Pd, Pt and Rh are continuously increased, especially Rh is extremely expensive, and the market requirement is continuously reduced. The general formula of the perovskite composite oxide is ABO 3 Research shows that perovskite oxides have the effect on CO, HC and NO x Has certain catalyst activity and can be used as a three-way catalyst for automobile exhaust.
Patent document CN112246251A discloses a natural gas automobile exhaust purification catalyst and a preparation method thereof. The preparation method comprises the following steps: la 0.67 Fe 0.83 Cu 0.17 O 3 Preparation of perovskite, Pd/Al 2 O 3 Preparing materials and preparing an integral catalyst; the catalyst component comprises Pd/Al 2 O 3 The catalyst and the perovskite are ball-milled and mixed in a ratio of 10-3: 1, the perovskite is prepared by a sol-gel method, and the pure perovskite catalyst prepared by the method is difficult to apply in practice due to a plurality of reasons such as small specific surface, difficult forming, low strength and the like. Patent CN111604050A discloses a method for preparing natural gas engine exhaust catalyst and treating lower hydrocarbons by catalyst oxidation, the engine exhaust catalyst uses ceo3 perovskite as catalytic carrier, and by controlling preparation process parameters and components of precursor solution, the perovskite catalyst with porous sponge structure is obtained, the disadvantage of insufficient specific surface area of perovskite material is effectively improved, the capture capacity of catalyst to exhaust gas molecules is improved, and the reaction time is prolonged. And meanwhile, noble metal elements are introduced to realize doping and surface loading of the perovskite B site, the porous sponge structure can be controlled by controlling preparation process parameters and components of a precursor solution in the technical scheme, but the preparation process parameters are complex, a good porous structure cannot be achieved, and industrial production is difficult. Therefore, it is required to develop a perovskite catalyst capable of preparing a large surface area and a method for preparing a catalyst having a high catalytic efficiencyAnd the tail gas can be more efficiently purified.
Disclosure of Invention
The invention aims to overcome the problems of small specific surface area of perovskite type catalysts and high cost of noble metal type catalysts in the prior art, and provides a natural gas vehicle tail gas purification catalyst and a preparation method thereof.
In order to achieve the above purpose, the invention provides the following technical scheme:
the catalyst comprises a catalyst carrier, and a first coating, a second coating and a third coating which are coated on the catalyst carrier in a segmented and/or layered mode, wherein the first coating is La x A y Mn z B 1-z O 3 The perovskite type composite oxide is loaded on the specific surface not less than 150m 2 The aluminum oxide or the first modified aluminum oxide is coated with the aluminum oxide or the first modified aluminum oxide, wherein x, y and z are molar values, x + y is less than or equal to 1, A is one of rare earth metal, alkali metal and alkaline earth metal, and B is one of transition metal Cu, Co, Ni, Fe and Cr; the second coating is formed by loading precious metal Pt and/or Pd on the first cerium-zirconium composite oxide and/or the second modified alumina; the third coating is formed by loading noble metals of Pt and Rh or Pd and Rh on a second cerium-zirconium composite oxide and/or third modified alumina; the second coating is arranged at the front end or the lower layer of the third coating.
The technical scheme provided by the invention is that the coating comprises a first coating, a second coating and a third coating, wherein the coating is in a segmented and/or layered integrated mode on the catalyst carrier, when the coating is in the segmented and layered mode, the first coating is positioned at the front section, the second coating is a bottom layer, the third coating is a top layer, and is positioned at the rear section, or the second coating is a bottom layer, the third coating is a top layer, and is positioned at the front section, the first coating is positioned at the rear section, the front section is a part close to the air inlet end in the catalyst coating, the rear section is a part close to the air outlet end in the catalyst coating, and the middle section is positioned between the front section and the rear end; the bottom layer is the part of the catalyst coating layer nearest to the wall surface of the catalyst carrier, the top layer is the part of the catalyst coating layer farthest from the wall surface of the catalyst carrier, and the middle layer is positioned at the top layer and the bottom layerBetween the layers; when the coating is in a segmented mode, the first coating is positioned at the front section or the middle section or the rear section, and the second coating is positioned at the front end of the third coating; when the coating is in a layered mode, the first coating is located on the bottom or middle layer or top layer of the catalyst, and the second coating is located under the third coating. Catalytic material La in the first coating x A y Mn z B 1-z O 3 In the perovskite type composite oxide, A or B site atoms can form lattice distortion after being substituted by external atoms to generate oxygen vacancies, the formation of the oxygen vacancies greatly increases the mobility of oxygen, can further enhance the activity of the catalyst, simultaneously increases the oxygen storage amount and can adjust the fluctuation of the air-fuel ratio, so that the first coating can be used as an oxygen storage material to effectively adjust the fluctuation of the air-fuel ratio and can be used as a noble metal catalyst to convert partial pollutants, and the second coating mainly plays an oxidation role and can oxidize HC and CO in the tail gas of a motor vehicle into CO 2 And H 2 O, the third coating mainly plays a role of reduction and can convert NO x Reduction to N 2 And H 2 And O. According to the invention, the first coating, the second coating and the third coating are integrated, the perovskite and the noble metal catalyst are applied in a layered or segmented coating mode, and the perovskite oxide partially replaces the noble metal, so that the conversion efficiency of the catalyst can be improved, the consumption of the noble metal can be reduced, and the purpose of saving the cost is achieved.
As a preferable scheme of the invention, the first modified alumina is one or more of lanthanum modified alumina, silicon modified alumina, zirconium modified alumina and magnesium modified alumina, and the content of lanthanum, silicon, zirconium and magnesium is 1-10 wt% in terms of oxide; the second modified alumina is one or more of lanthanum modified alumina, cerium modified alumina, zirconium modified alumina, barium modified alumina, yttrium modified alumina and praseodymium modified alumina, and the content of lanthanum, cerium, zirconium, barium, yttrium and praseodymium is 1-30 wt% in terms of oxide; the third modified alumina is one or more of lanthanum modified alumina, cerium modified alumina, zirconium modified alumina, barium modified alumina, yttrium modified alumina and praseodymium modified alumina, and the content of lanthanum, cerium, zirconium, barium and praseodymium is 5-20 wt% in terms of oxide;
as a preferable mode of the present invention, the specific surface area of the alumina or the first modified alumina is not less than 180m 2 (ii) in terms of/g. The first coating adopts a catalytic material with a large specific surface area, which is beneficial to improving the catalytic efficiency. Further, the specific surface area of the alumina or the first modified alumina is not less than 250m 2 (ii) in terms of/g. Still further, the specific surface area of the alumina or the first modified alumina is not less than 280m 2 /g。
In a preferred embodiment of the present invention, a is one of rare earth metals Ce, Pr, Nd, Sm, Eu, one of alkali metals Li, Na, K, Rb, Cs, or one of alkaline earth metals Mg, Ca, Sr, Ba.
As a preferable aspect of the present invention, the first cerium-zirconium composite oxide comprises, in mass percent: 20 to 80 wt% of CeO 2 、15～75wt％ZrO 2 And 5 to 20 wt% of La 2 O 3 、Y 2 O 3 、Pr 6 O 11 、Nd 2 O 3 One or more of them. The second cerium-zirconium composite oxide comprises the following components in percentage by mass: 20 to 80 wt% of CeO 2 、15～75wt％ZrO 2 And 5 to 20 wt% of La 2 O 3 、Y 2 O 3 、Pr 6 O 11 、Nd 2 O 3 One or more of them.
As a preferred aspect of the present invention, when the coating layer adopts the segmented mode, the first coating layer is located at the front segment.
As a preferred embodiment of the present invention, when the coating layer adopts a layered mode, the first coating layer is located on the bottom layer.
As a preferable aspect of the present invention, when the coating layer adopts a segmented mode, the coating length of the first coating layer is 10% to 40% of the catalyst carrier; the coating length of the second coating layer is 20-50% of the catalyst carrier; the coating length of the third coating layer is 20-50% of the catalyst carrier.
As a preferable scheme of the invention, when the second coating is a lower layer and the third coating is a top layer and is positioned at the rear section or the front section in a layered mode, the coating length of the first coating is 30-70% of the catalyst carrier; the coating length of the second coating layer or the third coating layer is 30-70% of the catalyst carrier.
As a preferable aspect of the present invention, the catalyst support is a ceramic honeycomb support.
In a preferred embodiment of the present invention, the ratio of the perovskite-type composite oxide to the alumina or the first modified alumina in the first coating layer is 10 to 70 wt%.
As a preferred embodiment of the present invention, the total content of the noble metals Pt and Pd in the second coating layer is not more than 30g/ft 3 (ii) a In the third coating, the total content of the noble metals of Pt, Rh or Pd and Rh does not exceed 20g/ft 3 Wherein the content of the noble metal Rh is not more than 3g/ft 3 。
The invention also provides a preparation method of the natural gas vehicle tail gas purification catalyst, which comprises the following steps:
step S1, preparing a first powder material: respectively dissolving soluble salts corresponding to La, A, Mn and B in deionized water, adding complexing agent, dispersant and precipitant, adjusting pH of the solution to 5-11, and adding the solution with specific surface not less than 150m 2 The alumina or the first modified alumina is continuously stirred until a uniform sol is formed on the surface of the alumina or the first modified alumina; evaporating the sol to dryness, drying and roasting to obtain first powder;
preparing a second powder material: loading a noble metal salt solution containing Pt and/or Pd on the first cerium-zirconium composite oxide and/or the second modified alumina by an isometric impregnation method, and then drying and roasting to obtain second powder;
preparing third powder: loading a noble metal salt solution containing Pt and Rh or Pd and Rh on a second cerium-zirconium composite oxide and/or a third modified alumina by an isometric impregnation method, and then drying and roasting to obtain third powder;
step S2, mixing the first powder, the second powder and the third powder with a binder respectively, and performing ball milling and pulping to obtain first slurry, second slurry and third slurry respectively;
and step S3, coating the first slurry, the second slurry and the third slurry on the catalyst carrier respectively, drying each slurry after coating, coating the next slurry, and roasting the slurry after all the slurries are coated to obtain the natural gas vehicle tail gas purification catalyst.
As a preferable scheme of the invention, the soluble salts corresponding to La, A, Mn and B comprise nitrate or acetate or oxalate or sulfate.
As a preferable scheme of the invention, the complexing agent comprises one of citric acid, oxalic acid and EDTA, and the molar ratio of the complexing agent to the total metal ions is 0.5-2; the dispersing agent comprises one of ethylene glycol, glycerol, polyethylene glycol and polyvinyl alcohol, and the addition amount of the dispersing agent is 0.5-8 wt%; the precipitator is one or more of NaOH, ammonium carbonate and ammonia water, and the concentration of the precipitator is 2-5.5 mol/L.
As a preferred scheme of the invention, when the first powder is prepared, the sol is dried by distillation, dried for 8-20h at 80-120 ℃, and roasted for 4-8h at 650-800 ℃; when the second powder is prepared, after the noble metal solution is loaded, drying the powder at 80-120 ℃ for 2-10h, and roasting the powder at 500-550 ℃ for 2-5h in the air atmosphere; when preparing the third powder, after loading the noble metal solution, drying at 80-120 ℃ for 2-10h, and roasting at 500-550 ℃ for 2-5h in air atmosphere; drying at 60-120 deg.C for 2-5h, and calcining at 500-550 deg.C in air atmosphere for 2-5 h.
In a preferred embodiment of the present invention, the binder is one of aluminum sol, silica sol, and zirconium sol, and the amount of the binder added is 2 to 8 wt% of the first powder, the second powder, or the third powder.
As a preferable scheme of the invention, the loading capacity of the first slurry is 50-180g/L, the loading capacity of the second slurry is 60-150g/L, and the loading capacity of the third slurry is 60-150 g/L.
As a preferable scheme of the invention, after the first slurry, the second slurry and the third slurry are coated on the catalyst carrier, each slurry is dried for 2-5h at 60-120 ℃ after being coated, and then the next slurry is coated after being dried, and the slurry is roasted for 2-5h in an air atmosphere at 500-550 ℃ after being coated completely.
Compared with the prior art, the invention has the beneficial effects that:
the catalyst prepared by the invention is applied to an exhaust system of a natural gas equivalent combustion engine, because the air-fuel ratio of the engine always fluctuates near lambda 1, when tail gas passes through a first coating, the catalyst can adjust the air-fuel ratio, when the oxygen content in the tail gas is high (lambda is more than 1), the perovskite catalyst can absorb and store oxygen, and when the oxygen content in the tail gas is low (lambda is less than 1), the perovskite catalyst can release oxygen, so that the fluctuation range of the air-fuel ratio is reduced, and the catalyst is more beneficial to always keeping the state of CO and CH 4 、NO x The three are within the range of a high-efficiency transformation window. Meanwhile, the perovskite catalyst can purify partial CO and NO x And CH 4 A contaminant. After the tail gas passes through the second coating, most of CH 4 And CO is oxidatively converted to CO 2 、H 2 O and N 2 While the catalyst exothermically heats up to cause CH 4 Steam reforming reaction to produce H 2 And CO, residual CH after oxygen consumption 4 CO and newly formed CO and H 2 NO in the system is further coated by a third coating x The conversion is carried out, and the effective conversion of the three pollutants is realized. When the coating adopts a segmented mode, the first coating is positioned at the front segment or the coating adopts a layered mode, the first coating is positioned at the lowest layer, and the prepared catalyst has better tail gas conversion efficiency.
The catalyst of the invention loads the perovskite composite oxide on the alumina with large specific surface area or the first modified alumina, can fully exert the oxygen storage and release function and the catalytic function of the perovskite, convert part of pollutants and simultaneously adjust the fluctuation of the air-fuel ratio, can improve the activity of the catalyst after being matched with the oxidized and reduced catalysts, can fully exert the catalytic function and the performance of adjusting the fluctuation of the air-fuel ratio of the perovskite, improve the conversion efficiency of the catalyst, reduce the emission of pollutants, thereby reducing the consumption of noble metals and saving the cost. The preparation method is simple in preparation process, easy to realize and suitable for industrial production.
Description of the drawings:
FIG. 1 is a schematic cross-sectional view of the catalyst preparation by segmented coating in example 1;
FIG. 2 is a flow chart of the preparation of the catalyst in example 1;
FIG. 3 is a schematic cross-sectional view of the catalyst preparation by the segmented coating in example 2;
FIG. 4 is a schematic cross-sectional view of the catalyst preparation by the segmented coating in example 3;
FIG. 5 is a schematic cross-sectional view of the catalyst preparation by the layered segmented coating in example 4;
FIG. 6 is a schematic cross-sectional view of the catalyst prepared by the layer coating in example 5;
FIG. 7 is a schematic cross-sectional view of the catalyst prepared by the layer coating in example 6;
FIG. 8 is a schematic cross-sectional view of the catalyst prepared by the layer coating in example 7;
FIG. 9 shows catalyst CH of examples 1, 4 and 5 and comparative examples 1 and 5 4 The window scan of (1);
FIG. 10 shows the catalysts NO of examples 1, 4 and 5 and comparative examples 1 and 5 x The window scan of (1);
FIG. 11 is a window scan of the catalyst CO of examples 1, 4, 5 and comparative examples 1, 5;
the labels in the figure are: 1-catalyst carrier, 2-first coating, 3-second coating, 4-third coating, 5-air inlet end and 6-air outlet end.
Detailed Description
The present invention will be described in further detail with reference to test examples and specific embodiments. It should be understood that the scope of the above-described subject matter is not limited to the following examples, and any techniques implemented based on the disclosure of the present invention are within the scope of the present invention.
Example 1
As shown in fig. 1, a natural gas vehicle exhaust purification catalyst comprises a catalyst carrier 1, and a first coating layer 2, a second coating layer 3, and a third coating layer 4 coated on the catalyst carrier 1, wherein the coating layers are coated on the catalyst carrier 1 in a segmented manner, the first coating layer 2 is positioned at a front section, the second coating layer 3 is positioned at a middle section, and the third coating layer 4 is positioned at a rear section, the front section is a part of the catalyst coating layer close to an air inlet end 5, the rear section is a part of the catalyst coating layer close to an air outlet end 6, and the middle section is positioned between the front section and the rear end; the coating lengths of the first coating 2, the second coating 3 and the third coating 4 are 1/3, 1/3 and 1/3 of the carrier 1; the catalyst carrier is cordierite, the preparation method of the catalyst is shown in figure 2, and the specific steps are as follows:
step S1, respectively dissolving nitrates corresponding to La, Sr, Mn and Co in deionized water, wherein the molar ratio is La: sr: mn: adding ethylene glycol and citric acid, wherein the adding amount of the ethylene glycol is 2 wt% of the aqueous solution, and the molar ratio of the citric acid to the total metal ions is 1: 1. adding ammonia water, adjusting pH to 8, and adding 280m specific surface 2 The perovskite accounts for 30 percent of the weight of the alumina with large specific surface, and the perovskite is continuously stirred at 90 ℃ until uniform sol is formed on the surface of the alumina or the first modified alumina; the sol was evaporated to dryness, then dried at 120 ℃ for 15h and calcined at 700 ℃ for 5h to obtain first powder SA 1.
Platinum nitrate and palladium nitrate solution are loaded on the cerium-zirconium composite oxide and the cerium, zirconium and lanthanum modified alumina by an equal-volume impregnation method, and the total content of Pt and Pd in the second coating 3 is 25g/ft 3 The content ratio of Pt to Pd is 4: 1, drying at 90 ℃ for 5 hours, and roasting at 550 ℃ in an air atmosphere for 2 hours to obtain second powder material SB 1;
loading platinum nitrate and rhodium nitrate solution on the cerium-zirconium composite oxide and lanthanum-zirconium modified alumina by an equal-volume impregnation method, wherein the total content of Pt and Rh in the third coating 4 is 15g/ft 3 The content ratio of Pt to Rh was 9:1, then dried at 80 ℃ for 8h and calcined at 500 ℃ in an air atmosphere for 3h to obtain a third powder SC 1.
And S2, mixing the first powder SA1, the second powder SB1 and the third powder SC1 with alumina sol respectively, adding deionized water and carrying out ball milling for 20min, wherein the alumina sol accounts for 7% of the first powder SA1, the second powder SB1 or the third powder SC1, and obtaining first slurry, second slurry and third slurry respectively, and the solid content of each slurry is 45%.
Step S3, coating the first slurry on the front section 1/3 of the cordierite carrier with the coating amount of 100g/L, drying for 5 hours at 90 ℃, coating the second slurry on the middle section 1/3 of the cordierite carrier with the coating amount of 100g/L, and drying for 5 hours at 90 ℃; the third slurry was applied to a rear stage 1/3 of a cordierite carrier at a coating amount of 100g/L, dried at 90 ℃ for 5 hours and calcined at 500 ℃ for 2 hours to obtain catalyst S1 of the present example.
Example 2
This example is similar to example 1 except that the second coating 3 is located at the front section, the first coating 2 is located at the middle section, and the third coating 4 is located at the rear section, as shown in fig. 3.
The catalyst S2 of this example was obtained according to the preparation method of example 1.
Example 3
This embodiment is similar to embodiment 1 except that the second coating layer 3 is located at the front section, the third coating layer 4 is located at the middle section, and the first coating layer 2 is located at the rear section, as shown in fig. 4.
The catalyst S3 of this example was obtained according to the preparation method of example 1.
Example 4
This example is similar to example 1 except that the first coat layer 2 is located at the front stage, the second coat layer 3 is a bottom layer, and the third coat layer 4 is a top layer, which are layered and located at the rear stage, as shown in fig. 5, the bottom layer is the portion of the catalyst coat layer closest to the wall surface of the catalyst carrier 1, the top layer is the portion of the catalyst coat layer farthest from the wall surface of the catalyst carrier 1, and the intermediate layer is located between the top layer and the bottom layer.
The catalyst S4 of this example was obtained according to the preparation method of example 1.
Example 5
This example is similar to example 1 except that the coatings are applied in layers, with the first coating 2 on the bottom layer, the second coating 3 on the middle layer and the third coating 4 on the top layer, as shown in figure 6.
The catalyst S5 of this example was obtained according to the preparation method of example 1.
Example 6
This example is similar to example 1 except that the coating layers are applied in layers, the second coating layer 3 being on the bottom layer, the first coating layer 2 being on the middle layer and the third coating layer 4 being on the top layer, as shown in fig. 7.
The catalyst S6 of this example was obtained according to the preparation method of example 1.
Example 7
This example is similar to example 1 except that the coatings are applied in layers, with the second coating 3 on the bottom layer, the third coating 4 on the middle layer and the first coating 2 on the top layer, as shown in fig. 8.
The catalyst S7 of this example was obtained according to the preparation method of example 1.
Example 8
This example is similar to example 1, except that the first powder was prepared differently from example 1, specifically: respectively dissolving nitrates corresponding to La, Sr, Mn and Co in deionized water, wherein the molar ratio is La: sr: mn: adding glycerol and EDTA, wherein the molar ratio of the EDTA to the total metal ions is 1: 1. then NaOH is added, the pH value of the solution is adjusted to 9, and then the solution is added with the specific surface of 180m 2 The perovskite accounts for 30 percent of the weight of the alumina, and is continuously stirred at the temperature of 90 ℃ until uniform sol is formed on the surface of the alumina or the first modified alumina; the sol was evaporated to dryness, then dried at 120 ℃ for 15h and calcined at 700 ℃ for 5h to obtain first powder SA 2.
The first powder SA2 prepared in this example, the second powder SB1 prepared in example 1 and the third powder SC1 were subjected to the steps S2 and S3 of example 1 to prepare a catalyst S8 of this example.
Example 9
This example is similar to example 1, except that the first powder was prepared differently from example 1, specifically: respectively dissolving nitrates corresponding to La, Ce, Mn and Cu in deionized water, wherein the molar ratio of the nitrates to the nitrates is La: ce: mn: adding ethylene glycol and citric acid, wherein the adding amount of the ethylene glycol is 2 wt% of the aqueous solution, and the molar ratio of the citric acid to the total metal ions is 1.5: 1. adding ammonia water, regulating pH value to 7, and adding ammonia waterThe post-addition specific surface area is 280m 2 The perovskite accounts for 30 percent of the weight of the alumina, and is continuously stirred at the temperature of 100 ℃ until uniform sol is formed on the surface of the alumina or the first modified alumina; the sol was evaporated to dryness, then dried at 110 ℃ for 20h and calcined at 650 ℃ for 8h to obtain a first powder SA 3.
The first powder SA3 prepared in this example, the second powder SB1 prepared in example 1 and the third powder SC1 were subjected to the steps S2 and S3 of example 1 to prepare a catalyst S9 of this example.
Comparative example 1
In this example, using the second powder SB1 and the third powder SC1 prepared in example 1, a second slurry and a third slurry were prepared in accordance with step S2, respectively.
Step S3, coating the second slurry on the front end 1/2 of the cordierite carrier, and drying for 5 hours at 90 ℃; the third slurry was applied to the latter stage 1/2 of cordierite carrier, dried at 90 ℃ for 5 hours, calcined at 500 ℃ for 2 hours, and the amount of each noble metal in this example was controlled to be exactly the same as that in example 1, to obtain catalyst D1 of this example.
Comparative example 2
This example is similar to example 1, except that there is no first coating and the second and third powders are prepared differently from example 1, specifically:
step S1, loading platinum nitrate and palladium nitrate solution on the cerium zirconium composite oxide and the second modified alumina by an isometric impregnation method, wherein the total content of Pt and Pd in the second coating 3 is 30g/ft 3 The content ratio of Pt to Pd is 4: 1, drying at 90 ℃ for 5 hours, and roasting at 550 ℃ in an air atmosphere for 2 hours to obtain second powder DB 1;
loading platinum nitrate and rhodium nitrate solution on the cerium-zirconium composite oxide and the third modified alumina by an equal-volume impregnation method, wherein the total content of Pt and Rh in the third coating 4 is 20g/ft 3 The content ratio of Pt to Rh was 9:1 were then dried at 80 ℃ for 8h and calcined at 500 ℃ in an air atmosphere for 3h to give a third powder DC 1.
And S2, mixing the second powder DB1 and the third powder DC1 with the alumina sol respectively, adding water ionized water, and performing ball milling for 20min to obtain second slurry and third slurry respectively, wherein the solid content is 45%.
Step S3, coating the second slurry on the front end 1/2 of the cordierite carrier, and drying for 5 hours at 90 ℃; the third slurry was applied to the latter stage 1/2 of cordierite carrier, dried at 90 ℃ for 5 hours and calcined at 500 ℃ for 2 hours to obtain catalyst D2 of this example.
Comparative example 3
This example is similar to example 1, except that the first powder was prepared differently from example 1, specifically: respectively dissolving nitrates corresponding to La, Sr, Mn and Co in deionized water, wherein the molar ratio is La: sr: mn: adding ethylene glycol and citric acid, wherein the molar ratio of the citric acid to the total metal ions is 1: 1. adding ammonia water, adjusting pH to 8, and adding 100m specific surface 2 The perovskite accounts for 30 percent of the weight of the alumina with large specific surface, and the perovskite is continuously stirred at 90 ℃ until uniform sol is formed on the surface of the alumina or the first modified alumina; and (3) evaporating the sol to dryness, then drying at 120 ℃ for 15h, and roasting at 700 ℃ for 5h to obtain first powder DA 1.
The first powder DA1 prepared in this example, the second powder SB1 prepared in example 1 and the third powder SC1 were subjected to the steps S2 and S3 of example 1 to prepare a catalyst D3 according to this example.
Comparative example 4
Step S1, respectively dissolving nitrates corresponding to La, Sr, Mn and Co in deionized water, wherein the molar ratio is La: sr: mn: adding ethylene glycol into the citric acid, wherein the adding amount of the ethylene glycol is 2 wt% of the aqueous solution, and the molar ratio of the citric acid to the total metal ions is 1: 1. and adding ammonia water, adjusting the pH value of the solution to 8, evaporating the solution to dryness, drying at 120 ℃ for 15h, and roasting at 700 ℃ for 5h to obtain first powder DA 2.
The second powder DB2 and the third powder DC2 of example 1 were used as the second powder SB1 and the third powder SC1, respectively
Step S2, adding the first powder DA2 into the second powder DB2 and the third powder DC2 respectively, and mixing, wherein the ratio of the first powder DA2 to the second powder DB2 or the third powder DC2 is 1: and 4, respectively mixing the mixture with the alumina sol, adding water ionized water, and carrying out ball milling for 20min to respectively obtain second slurry and third slurry.
Step S3, coating the second slurry on the front end 1/2 of the cordierite carrier, and drying for 5 hours at 90 ℃; the third slurry was applied to the latter stage 1/2 of cordierite carrier, dried at 90 ℃ for 5 hours, calcined at 500 ℃ for 2 hours, and the amount of each noble metal in this example was controlled to be exactly the same as that in example 1, to obtain catalyst D4 of this example.
Comparative example 5
In this example, using the second powder SB1 and the third powder SC1 prepared in example 1, a second slurry and a third slurry were prepared in accordance with step S2, respectively.
Step S3, coating the second slurry on the bottom layer 1/2 of the cordierite carrier, drying the cordierite carrier at 90 ℃ for 5 hours, and roasting the cordierite carrier at 500 ℃ for 2 hours; the third slurry was applied to the top layer 1/2 of a cordierite carrier, dried at 90 ℃ for 5 hours, and calcined at 500 ℃ for 2 hours, and the amount of each noble metal in this example was controlled to be exactly the same as that in example 1, to obtain catalyst D5 of this example.
Test example 1
The catalysts of examples 1 to 9 and comparative examples 1 to 5 were subjected to an activity test in an atmosphere of H concentration 2 3000ppm、CO 1％、NO 1000ppm、CH 4 3000ppm、CO 2 5％、H 2 O 10％，N 2 Is balance gas, and has space velocity of 40000h -1 By adjusting O 2 The concentration was such that the air-fuel ratio lambda was switched in turn between 0.963-0.993-1.003-0.993, each lambda value was maintained for 5s, and the structure of the conversion of the resulting catalyst to each pollutant at 300 ℃ is shown in Table 1.
Table 1 conversion data for catalysts for each contaminant
| Number of | CO conversion (%) | CH 4 Conversion (%) | NO x Conversion (%) |
| Example 1 | 99 | 98 | 99 |
| Example 2 | 100 | 95 | 94 |
| Example 3 | 99 | 94 | 93 |
| Example 4 | 100 | 96 | 99 |
| Example 5 | 100 | 97 | 98 |
| Example 6 | 99 | 95 | 98 |
| Example 7 | 100 | 94 | 99 |
| Example 8 | 99 | 92 | 95 |
| Example 9 | 100 | 98 | 98 |
| Comparative example 1 | 100 | 80 | 88 |
| Comparative example 2 | 99 | 96 | 98 |
| Comparative example 3 | 100 | 87 | 94 |
| Comparative example 4 | 99 | 75 | 83 |
| Comparative example 5 | 99 | 83 | 87 |
Test example 2
The catalysts of example 1, example 4 and example 5 and comparative example 1 and comparative example 5 were subjected to a window scan test in an atmosphere concentration similar to that of the activity test atmosphere by adjusting O 2 Concentrations were switched sequentially between 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 0.994, 0.998, 1, 1.004, 1.008, 1.01, 1.02, 1.03, 1.04, respectively, with each lambda value held for 1min, and the air-fuel ratio windows for each catalyst were tested at 500 ℃, with the data shown in fig. 9, 10, 11.
Combining the data in Table 1 and FIGS. 9, 10, and 11, the coatings for the catalysts of examples 1, 2, and 3 were all applied in segmented fashion, with example 1 catalyst on CH 4 And NO x Is slightly higher than in examples 2 and 3, which shows that the use of the segmented coating allows better adjustment of the air-fuel ratio when the first coating is located at the front segment. Example 4 catalyst coatings were layered and segmented, example 1 catalyst vs. CH 4 Slightly higher conversion than in example 4; the coating of the catalysts of example 5, example 6 and example 7 are all applied in a layered manner, and the catalyst of example 5 is applied to CH 4 Is slightly higher than in examples 6 and 7, which shows that the air-fuel ratio can be adjusted better with the layered coating when the first coating is in the lowermost layer. Example 9 the composition of the perovskite-type composite oxide of the first coating layer of the catalyst was changed, and the catalyst of example 9 was paired with CH as compared with example 1 4 And NO x The conversion of (a) is not greatly different.
Example 1 in comparison to comparative example 1, where the precious metal content was the same, no perovskite was added to comparative example 1 and the catalyst of comparative example 1 was paired with CH 4 And NO x Is significantly lower than in example 1 and comparative example 1 on CH 4 、NO x The window for CO conversion was narrower than in example 1; examples 4, 5, 6, 7 compared to comparative example 5, when the noble metal content was the same, no perovskite was added in comparative example 5 and the catalyst of comparative example 5 was paired with CH 4 And NO x Has a significantly low conversion rateIn examples 4-7, and comparative example 5 for CH 4 、NO x The CO conversion window was narrower than in examples 4 and 5. Example 1 in comparison to comparative example 2, with perovskite added in example 1 and no perovskite but increased noble metal usage in comparative example 2, the catalysts of example 1 and comparative example 2 are data on CH 4 And NO x The conversion rate of the perovskite composite oxide is equivalent, which shows that the first coating formed by loading the perovskite composite oxide on the large-specific-surface alumina or the first modified alumina can fully exert the oxygen storage and storage functions and the catalytic function of the perovskite, convert part of pollutants and simultaneously adjust the fluctuation of the air-fuel ratio, after the perovskite composite oxide is matched with the oxidized catalyst and the reduced catalyst for use, the activity of the catalyst can be improved, the catalytic function of the perovskite and the performance of adjusting the fluctuation of the air-fuel ratio can be fully exerted, the conversion efficiency of the catalyst is improved, the emission of pollutants is reduced, the consumption of noble metals is reduced, and the cost is saved.
The specific surface areas of the catalytic materials in the first coating layers of the catalysts of example 1, example 8 and comparative example 3 were 280m, respectively 2 /g、180m 2 /g、100m 2 Catalyst pair CH 4 And NO x With the conversion of example 8 on CH, increasing with the increase of the specific surface area of the catalytic material 4 Conversion of (2) was 92%, comparative example 3 was for CH 4 The conversion of (A) was only 87%. Example 1 in comparison with comparative example 4, comparative example 4 in which the perovskite composite oxide of the first coating layer was not supported on alumina but was mechanically mixed with noble metal powder, comparative example 4 in which the catalyst was paired with CH 4 And NO x The conversion rate of (A) is significantly lower than that of example 1, which shows that the perovskite composite oxide of the first coating layer needs to be supported on alumina or first modified alumina with a large specific surface, and the specific surface of the alumina or first modified alumina is not less than 150m 2 /g。
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. Natural gasThe catalyst for purifying the tail gas of the vehicle is characterized by comprising a catalyst carrier, and a first coating, a second coating and a third coating which are coated on the catalyst carrier in a segmented and/or layered mode, wherein the first coating is La x A y Mn z B 1-z O 3 The perovskite type composite oxide is loaded on the specific surface not less than 150m 2 The aluminum oxide or the first modified aluminum oxide is coated with the aluminum oxide or the first modified aluminum oxide, wherein x, y and z are molar values, x + y is less than or equal to 1, A is one of rare earth metal, alkali metal and alkaline earth metal, and B is one of transition metal Cu, Co, Ni, Fe and Cr; the second coating is formed by loading noble metal Pt and/or Pd on the first cerium-zirconium composite oxide and/or the second modified alumina; the third coating is formed by loading noble metals of Pt and Rh or Pd and Rh on a second cerium-zirconium composite oxide and/or third modified alumina; the second coating is arranged at the front end or the lower layer of the third coating.
2. The natural gas vehicle tail gas purification catalyst according to claim 1, wherein a is one of rare earth metals Ce, Pr, Nd, Sm, Eu or one of alkali metals Li, Na, K, Rb, Cs or one of alkaline earth metals Mg, Ca, Sr, Ba.
3. The natural gas vehicle tail gas purification catalyst according to claim 1, wherein the specific surface area of the alumina or the first modified alumina is not less than 180m 2 /g。
4. The natural gas vehicle tail gas purification catalyst as claimed in claim 1, wherein when the coating layer adopts a segment mode, the first coating layer is located at the front segment; when the coating is in a layered mode, the first coating is on the bottom layer.
5. The natural gas vehicle tail gas purification catalyst according to claim 1, wherein the ratio of the perovskite-type composite oxide to alumina or first modified alumina in the first coating layer is 10 to 70 wt%.
6. The natural gas vehicle tail gas purification catalyst as claimed in claim 1, wherein the total content of noble metals Pt and Pd in the second coating layer is not more than 30g/ft 3 (ii) a In the third coating, the total content of the noble metals of Pt, Rh or Pd and Rh does not exceed 20g/ft 3 Wherein the content of the noble metal Rh is not more than 3g/ft 3 。
7. A method for preparing a catalyst for purifying tail gas of a natural gas vehicle according to any one of claims 1 to 6, which comprises the following steps:
step S1, preparing a first powder material: respectively dissolving soluble salts corresponding to La, A, Mn and B in deionized water, adding complexing agent, dispersant and precipitant, adjusting pH of the solution to 5-11, and adding the solution with specific surface not less than 150m 2 The method comprises the following steps of (1) continuously stirring alumina or first modified alumina until uniform sol is formed on the surface of the alumina or the first modified alumina; evaporating the sol to dryness, drying and roasting to obtain first powder;
preparing a second powder material: loading a noble metal salt solution containing Pt and/or Pd on the first cerium-zirconium composite oxide and/or the second modified alumina by an isometric impregnation method, and then drying and roasting to obtain second powder;
preparing third powder: loading a noble metal salt solution containing Pt and Rh or Pd and Rh on a second cerium-zirconium composite oxide and/or a third modified alumina by an isometric impregnation method, and then drying and roasting to obtain third powder;
step S2, mixing the first powder, the second powder and the third powder with an adhesive respectively, and performing ball milling and pulping to obtain first slurry, second slurry and third slurry respectively;
and step S3, coating the first slurry, the second slurry and the third slurry on the catalyst carrier respectively, drying each slurry after coating, coating the next slurry, and roasting the slurry after all the slurries are coated to obtain the natural gas vehicle tail gas purification catalyst.
8. The method for preparing a natural gas vehicle tail gas purification catalyst according to claim 1, wherein the complexing agent comprises one of citric acid, oxalic acid and EDTA; the dispersing agent comprises one of ethylene glycol, glycerol, polyethylene glycol and polyvinyl alcohol; the precipitator is one or more of NaOH, ammonium carbonate and ammonia water.
9. The method for preparing a natural gas vehicle tail gas purification catalyst according to claim 1, wherein the loading amount of the first slurry is 50-180g/L, the loading amount of the second slurry is 60-150g/L, and the loading amount of the third slurry is 60-150 g/L.
10. The method for preparing a catalyst for purifying tail gas of a natural gas vehicle as claimed in claim 1, wherein after the first slurry, the second slurry and the third slurry are coated on the catalyst carrier, each slurry is dried at 60-120 ℃ for 2-5h, and after the drying, the next slurry is coated, and after the slurry is completely coated, the slurry is roasted at 500-550 ℃ for 2-5 h.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115970687A (en) * | 2023-01-31 | 2023-04-18 | 中自环保科技股份有限公司 | Pt-based natural gas tail gas purification catalyst and preparation method thereof |
| CN116251592A (en) * | 2023-01-31 | 2023-06-13 | 昆明贵研催化剂有限责任公司 | Post-treatment catalyst for hybrid electric vehicle, preparation method and application thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0734757A1 (en) * | 1995-03-31 | 1996-10-02 | General Motors Corporation | Catalytic converter having tri precious metal catalysts |
| CN1714931A (en) * | 2004-06-14 | 2006-01-04 | 中国科学院生态环境研究中心 | The perovskite type rare earth complex oxide catalyst of catalytic decomposition NOx under the excess oxygen |
| CN101274215A (en) * | 2007-12-27 | 2008-10-01 | 清华大学 | Rare earth perovskite type oxygen storage material for purifying vehicle tail gas |
| CN101632930A (en) * | 2008-07-25 | 2010-01-27 | 比亚迪股份有限公司 | Catalyst for purifying automobile tail gas and preparation method thereof |
| CN103143351A (en) * | 2013-03-15 | 2013-06-12 | 无锡威孚环保催化剂有限公司 | Ternary catalyst |
| CN107597127A (en) * | 2017-08-16 | 2018-01-19 | 柳州申通汽车科技有限公司 | A kind of ternary catalyst for automobile tail gas |
| CN109603823A (en) * | 2019-01-09 | 2019-04-12 | 无锡威孚环保催化剂有限公司 | The lean-burn NO of diesel engine vent gas purification systemxTrap catalyst and preparation method thereof |
| CN109876807A (en) * | 2019-03-17 | 2019-06-14 | 中自环保科技股份有限公司 | A kind of three-way catalyst preparation method and its catalyst with high NOx detergent power |
-
2022
- 2022-04-14 CN CN202210391348.2A patent/CN114870860B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0734757A1 (en) * | 1995-03-31 | 1996-10-02 | General Motors Corporation | Catalytic converter having tri precious metal catalysts |
| CN1714931A (en) * | 2004-06-14 | 2006-01-04 | 中国科学院生态环境研究中心 | The perovskite type rare earth complex oxide catalyst of catalytic decomposition NOx under the excess oxygen |
| CN101274215A (en) * | 2007-12-27 | 2008-10-01 | 清华大学 | Rare earth perovskite type oxygen storage material for purifying vehicle tail gas |
| CN101632930A (en) * | 2008-07-25 | 2010-01-27 | 比亚迪股份有限公司 | Catalyst for purifying automobile tail gas and preparation method thereof |
| CN103143351A (en) * | 2013-03-15 | 2013-06-12 | 无锡威孚环保催化剂有限公司 | Ternary catalyst |
| CN107597127A (en) * | 2017-08-16 | 2018-01-19 | 柳州申通汽车科技有限公司 | A kind of ternary catalyst for automobile tail gas |
| CN109603823A (en) * | 2019-01-09 | 2019-04-12 | 无锡威孚环保催化剂有限公司 | The lean-burn NO of diesel engine vent gas purification systemxTrap catalyst and preparation method thereof |
| CN109876807A (en) * | 2019-03-17 | 2019-06-14 | 中自环保科技股份有限公司 | A kind of three-way catalyst preparation method and its catalyst with high NOx detergent power |
Non-Patent Citations (2)
| Title |
|---|
| XING ZHU ET AL.: "Perovskites as Geo-inspired Oxygen Storage Materials for Chemical Looping and Three-Way Catalysis: A Perspective", 《ACS CATALYSIS》, pages 8213 - 8236 * |
| 刘志军: "机动车尾气净化催化剂的研究与展望", 《化工设计通讯》, no. 08, pages 237 - 245 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115970687A (en) * | 2023-01-31 | 2023-04-18 | 中自环保科技股份有限公司 | Pt-based natural gas tail gas purification catalyst and preparation method thereof |
| CN116251592A (en) * | 2023-01-31 | 2023-06-13 | 昆明贵研催化剂有限责任公司 | Post-treatment catalyst for hybrid electric vehicle, preparation method and application thereof |
| CN116251592B (en) * | 2023-01-31 | 2023-12-12 | 昆明贵研催化剂有限责任公司 | Post-treatment catalyst for hybrid electric vehicle, preparation method and application thereof |
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