CN106040235B - Exhaust gas purifying catalyst and its manufacturing method - Google Patents
Exhaust gas purifying catalyst and its manufacturing method Download PDFInfo
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- CN106040235B CN106040235B CN201610212807.0A CN201610212807A CN106040235B CN 106040235 B CN106040235 B CN 106040235B CN 201610212807 A CN201610212807 A CN 201610212807A CN 106040235 B CN106040235 B CN 106040235B
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- Prior art keywords
- exhaust gas
- gas purifying
- purifying catalyst
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- particle
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- 239000003054 catalyst Substances 0.000 title claims abstract description 175
- 238000004519 manufacturing process Methods 0.000 title abstract description 14
- 239000000203 mixture Substances 0.000 claims abstract description 122
- 239000002923 metal particle Substances 0.000 claims abstract description 114
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 86
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 85
- 239000002245 particle Substances 0.000 claims abstract description 69
- 239000012298 atmosphere Substances 0.000 claims description 74
- 239000000428 dust Substances 0.000 claims description 69
- 238000000034 method Methods 0.000 claims description 46
- 229910052751 metal Inorganic materials 0.000 claims description 40
- 230000009467 reduction Effects 0.000 claims description 32
- 239000002184 metal Substances 0.000 claims description 31
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 claims description 29
- 239000000463 material Substances 0.000 claims description 24
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 claims description 8
- 239000007791 liquid phase Substances 0.000 claims description 5
- 239000007789 gas Substances 0.000 abstract description 173
- 238000000746 purification Methods 0.000 abstract description 39
- 239000002912 waste gas Substances 0.000 abstract description 17
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 206
- 239000010948 rhodium Substances 0.000 description 184
- 230000000052 comparative effect Effects 0.000 description 60
- 150000002500 ions Chemical class 0.000 description 46
- 238000006722 reduction reaction Methods 0.000 description 37
- 239000000243 solution Substances 0.000 description 30
- 239000003638 chemical reducing agent Substances 0.000 description 29
- 238000011156 evaluation Methods 0.000 description 28
- 238000012360 testing method Methods 0.000 description 21
- 238000007254 oxidation reaction Methods 0.000 description 20
- 230000003647 oxidation Effects 0.000 description 19
- 150000002739 metals Chemical class 0.000 description 16
- 230000000694 effects Effects 0.000 description 15
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 12
- 239000004215 Carbon black (E152) Substances 0.000 description 11
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 11
- 229910002091 carbon monoxide Inorganic materials 0.000 description 11
- 229930195733 hydrocarbon Natural products 0.000 description 11
- 150000002430 hydrocarbons Chemical class 0.000 description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 9
- 239000011259 mixed solution Substances 0.000 description 9
- 239000001301 oxygen Substances 0.000 description 9
- 229910052760 oxygen Inorganic materials 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical group O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 239000003795 chemical substances by application Substances 0.000 description 8
- 239000003599 detergent Substances 0.000 description 8
- 230000002829 reductive effect Effects 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 230000036961 partial effect Effects 0.000 description 7
- 239000003223 protective agent Substances 0.000 description 7
- 238000010992 reflux Methods 0.000 description 7
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 6
- 230000004087 circulation Effects 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- 230000007246 mechanism Effects 0.000 description 6
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 6
- 238000000851 scanning transmission electron micrograph Methods 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 5
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 5
- ITHZDDVSAWDQPZ-UHFFFAOYSA-L barium acetate Chemical compound [Ba+2].CC([O-])=O.CC([O-])=O ITHZDDVSAWDQPZ-UHFFFAOYSA-L 0.000 description 5
- 238000009835 boiling Methods 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 5
- 238000001035 drying Methods 0.000 description 5
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 5
- 229910052737 gold Inorganic materials 0.000 description 5
- 239000010931 gold Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- RJIWZDNTCBHXAL-UHFFFAOYSA-N nitroxoline Chemical compound C1=CN=C2C(O)=CC=C([N+]([O-])=O)C2=C1 RJIWZDNTCBHXAL-UHFFFAOYSA-N 0.000 description 5
- 230000033116 oxidation-reduction process Effects 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 5
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 5
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- VVJKKWFAADXIJK-UHFFFAOYSA-N Allylamine Chemical compound NCC=C VVJKKWFAADXIJK-UHFFFAOYSA-N 0.000 description 4
- 230000002776 aggregation Effects 0.000 description 4
- 238000004220 aggregation Methods 0.000 description 4
- 229910052788 barium Inorganic materials 0.000 description 4
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 4
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 239000006104 solid solution Substances 0.000 description 4
- 229910001928 zirconium oxide Inorganic materials 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 3
- 239000000969 carrier Substances 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 3
- 229910052681 coesite Inorganic materials 0.000 description 3
- 229910052593 corundum Inorganic materials 0.000 description 3
- 229910052906 cristobalite Inorganic materials 0.000 description 3
- 239000010419 fine particle Substances 0.000 description 3
- 230000002401 inhibitory effect Effects 0.000 description 3
- 238000005342 ion exchange Methods 0.000 description 3
- 238000011068 loading method Methods 0.000 description 3
- 239000000395 magnesium oxide Substances 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 229910052682 stishovite Inorganic materials 0.000 description 3
- 229910052905 tridymite Inorganic materials 0.000 description 3
- 229910001845 yogo sapphire Inorganic materials 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 150000001299 aldehydes Chemical class 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000005660 chlorination reaction Methods 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000001246 colloidal dispersion Methods 0.000 description 2
- 239000000084 colloidal system Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 239000002274 desiccant Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 150000004820 halides Chemical class 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000007800 oxidant agent Substances 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 238000003908 quality control method Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- SONJTKJMTWTJCT-UHFFFAOYSA-K rhodium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Rh+3] SONJTKJMTWTJCT-UHFFFAOYSA-K 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- 238000010792 warming Methods 0.000 description 2
- SKSORCHTXOEUIU-UHFFFAOYSA-N 2-(aziridin-1-yl)acetic acid Chemical compound OC(=O)CN1CC1 SKSORCHTXOEUIU-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 description 1
- 229910052684 Cerium Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-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
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 101150003085 Pdcl gene Proteins 0.000 description 1
- 229920002873 Polyethylenimine Polymers 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- -1 bis- carboxymethyl Chemical group 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 235000009508 confectionery Nutrition 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000004482 other powder Substances 0.000 description 1
- 150000003891 oxalate salts Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 230000036284 oxygen consumption Effects 0.000 description 1
- HGBOYTHUEUWSSQ-UHFFFAOYSA-N pentanal Chemical compound CCCCC=O HGBOYTHUEUWSSQ-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 229920000083 poly(allylamine) Polymers 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 235000011056 potassium acetate Nutrition 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 230000005476 size effect Effects 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000000629 steam reforming Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/63—Platinum group metals with rare earths or actinides
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/002—Mixed oxides other than spinels, e.g. perovskite
-
- B01J35/61—
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
-
- 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
Abstract
The present invention relates to exhaust gas purifying catalyst and its manufacturing methods.The composition metal particle and its manufacturing method the purpose of the present invention is to provide a kind of exhaust gas purifying catalyst for waste gas purification, particularly wherein contained.Exhaust gas purifying catalyst of the invention has the composition metal particle containing Rh and Pd, when being analyzed using STEM-EDX the particle in exhaust gas purifying catalyst, Pd is 1.7 atom % or more, 24.8 atom % or less relative to total average proportions of Rh and Pd.
Description
Technical field
The present invention relates to exhaust gas purifying catalyst and its manufacturing methods.More specifically, the present invention relates to waste gas purifications
The exhaust gas purifying catalyst and its manufacturing method that can be improved.
Background technique
It is useless what is be discharged from the internal combustion engine (such as the internal combustion engines such as petrol engine or diesel engine) for automobile etc.
Contain harmful components, such as carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxides (NO in gasx) etc..
Therefore, setting utilizes peace for decomposing the waste gas purification apparatus for removing these harmful components usually in internal combustion engine
Exhaust gas purifying catalyst in the waste gas purification apparatus, these harmful components are most of innoxious.As such useless
Gas cleaning catalyst, it is known that have such as three-way catalyst and NOxOcclude reducing catalyst.
Three-way catalyst is under stoichiometric ratio (chemically correct fuel) atmosphere while to carry out oxidation and the NO of CO and HCx's
The catalyst of reduction.
In addition, NOxOccluding reducing catalyst is that the NO in exhaust gas is oxidized to NO under dilute atmosphere2And it occludes, and in chemistry
Metering is than being reduced into nitrogen (N under atmosphere and under dense atmosphere2) catalyst, dilute atmosphere, stoichiometric ratio is dexterously utilized
The variation of the exhaust gas constituents of atmosphere and dense atmosphere.
But even if the purification of exhaust gas is still problem, has carried out various grind using these catalyst
Study carefully.
The composition metal colloid of patent document 1 includes Determination of multiple metal elements, and the average grain diameter of the composition metal colloid is 2~
12nm, and Determination of multiple metal elements is distributed substantially uniformly through in the particle of the composition metal.Specifically, in patent document
In 1, disclose the composition metal colloidal dispersions for palladium chloride solution and rhodium chloride solution being mixed with 1:1 with molar ratio computing
Body.
The exhaust gas purifying catalyst of the CO or HC purification of patent document 2 has the alloy containing Pd and Ag, and the conjunction
Gold is supported at carrier.
Existing technical literature
Patent document
Patent document 1: special open 2002-102679 bulletin
Patent document 2: special open 2011-78857 bulletin
Summary of the invention
Problems to be solved by the invention
The object of the present invention is to provide a kind of exhaust gas purifying catalyst for waste gas purification, particularly wherein contain
Composition metal particle and its manufacturing method.
Means for solving the problems
The inventors discovered that by the following means, the above subject can be solved.
1 > exhaust gas purifying catalyst of < is the exhaust gas purifying catalyst with the composition metal particle containing Rh and Pd,
In,
When being analyzed using STEM-EDX the particle in above-mentioned exhaust gas purifying catalyst, Pd is relative to Rh and Pd
Total average proportions be 1.7 atom % or more, 24.8 atom % hereinafter,
Above-mentioned average proportions are by following calculated value: 10 or more are randomly choosed from exhaust gas purifying catalyst
Particle measures selected whole particles using STEM-EDX respectively, further selects from selected whole particles complete
The above-mentioned composition metal particle containing Rh and Pd in portion amounts to the Pd of above-mentioned each composition metal particle relative to the total of Rh and Pd
Ratio, with the total divided by the total number of the above-mentioned composition metal particle of selected whole.
The exhaust gas purifying catalyst recorded in 2 > < of < 1 > further has dust carrier, and above-mentioned composition metal
Particle is supported at above-mentioned dust carrier.
The exhaust gas purifying catalyst recorded in 3 > < of < 2 >, wherein above-mentioned dust carrier is selected from SiO2、MgO、ZrO2、
CeO2、Al2O3、TiO2, they solid solution and their combination dust carrier.
The exhaust gas purifying catalyst recorded in 4 > < of < 2 > or < 3 >, wherein relative to the quality of above-mentioned dust carrier, on
Dust carrier is stated with more than 0 mass % and 40 mass % or less contain CeO2。
5 > exhaust gas purifying method of <, wherein make under stoichiometric ratio atmosphere containing HC, CO and NOxExhaust gas and 1 > of <~
The exhaust gas purifying catalyst contact recorded in any one of < 4 >, thus by HC and CO oxidation and by NOxIt is also original to carry out only
Change.
6 > exhaust gas purifying method of <, wherein make under dilute atmosphere containing NOxExhaust gas and 1 > of <~<, 4 > any one in
The exhaust gas purifying catalyst of record contacts, by above-mentioned NO under dense atmospherexAlso purified originally.
The manufacturing method of 7 > exhaust gas purifying catalyst of < is to include to containing Rh ion, Pd ion, reducing agent and protection
The solution of agent is heated to reflux, and the manufacturing method of the exhaust gas purifying catalyst of composition metal particle is thus generated, wherein
The molar ratio of above-mentioned Rh ion and above-mentioned Pd ion is 70:30~99:1.
The method of 8 > < of < 7 > records comprising above-mentioned composition metal particle is supported at dust carrier.
The method recorded in 9 > < of < 8 >, wherein above-mentioned dust carrier is selected from SiO2、MgO、ZrO2、CeO2、Al2O3、
TiO2, they solid solution and their combination dust carrier.
The method recorded in 10 > < of < 8 > or < 9 >, wherein relative to the quality of above-mentioned dust carrier, above-mentioned dust carrier
With more than 0 mass % and 40 mass % or less contain CeO2。
Invention effect
In accordance with the invention it is possible to provide a kind of exhaust gas purifying catalyst for waste gas purification, particularly wherein contain
Composition metal particle and its manufacturing method.
Detailed description of the invention
Fig. 1 (a) is to utilize the scanning transmission electron microscope (STEM- with energy dispersion-type X-ray analytical equipment
EDX the STEM image of the exhaust gas purifying catalyst for the embodiment 1) analyzed, Fig. 1 (b) be show it is net from the exhaust gas of embodiment 1
Figure of the Pd of each particle relative to total ratio (atom %) of Rh and Pd in 10 particles extracted at random in change catalyst.
Fig. 2 (a) is the STEM image of the exhaust gas purifying catalyst for the embodiment 2 analyzed using STEM-EDX, Fig. 2
(b) be show the Pd of each particle from 10 particles extracted at random in the exhaust gas purifying catalyst of embodiment 2 relative to Rh and
The figure of total ratio (atom %) of Pd.
Fig. 3 (a) is the STEM image of the exhaust gas purifying catalyst for the embodiment 3 analyzed using STEM-EDX, Fig. 3
(b) be show the Pd of each particle from 10 particles extracted at random in the exhaust gas purifying catalyst of embodiment 3 relative to Rh and
The figure of total ratio (atom %) of Pd.
Fig. 4 (a) is the STEM image of the exhaust gas purifying catalyst for the comparative example 1 analyzed using STEM-EDX, Fig. 4
(b) be show the Pd of each particle from 10 particles extracted at random in the exhaust gas purifying catalyst of comparative example 1 relative to Rh and
The figure of total ratio (atom %) of Pd.
Fig. 5 (a) is the STEM image of the exhaust gas purifying catalyst for the comparative example 3 analyzed using STEM-EDX, Fig. 5
(b) be show the Pd of each particle from 10 particles extracted at random in the exhaust gas purifying catalyst of comparative example 3 relative to Rh and
The figure of total ratio (atom %) of Pd.
Fig. 6 is the evaluation condition about three-way catalyst, shows the figure of the relationship of time (minute) and temperature (DEG C).
Fig. 7 is the temperature shown when evaluating the activity of the exhaust gas purifying catalyst of Examples 1 to 3 and comparative example 1~3
Spend (DEG C) and NOxThe figure of the relationship of purifying rate (%).
Fig. 8 is shown to the Pd of the exhaust gas purifying catalyst of Examples 1 to 3 and comparative example 1 relative to the total of Rh and Pd
Average proportions (atom %) and NOxThe figure of the relationship of 50% purification temperature (DEG C).
Fig. 9 is the exhaust gas purifying catalyst and NO shown to Examples 1 to 3 and comparative example 1~3x50% purification temperature
The figure of the relationship of (DEG C).
Figure 10 is to show the carrier of Examples 1 to 3 and comparative example 1 being replaced as Al respectively2O3- ZrO2- TiO2And
Wherein be added to embodiment 1 '~3 ' of barium acetate and the exhaust gas purifying catalyst of comparative example 1 ' sample be exposed to dilute atmosphere and
Time (second) and NO when dense atmospherexThe figure of the relationship of discharge rate (ppm).
Figure 11 is the enlarged drawing amplified of a part about Figure 10.
Figure 12 is shown as NOxIn the performance evaluation B for occluding reducing catalyst, it is made of dilute atmosphere and dense atmosphere
, NOxOcclude the schematic diagram of 1 cyclic part of reduction circulation.
Figure 13 is the sample of the exhaust gas purifying catalyst about embodiment 4~11 (●) and comparative example 4~11 (■), is shown
CeO in dust carrier2Content (quality %) and NOxDischarge rate/NOxThe figure of the relationship of hold-up (a.u.).
Figure 14 is the sample of the exhaust gas purifying catalyst about embodiment 4~11 (●) and comparative example 4~11 (■), is shown
CeO in dust carrier2Content (quality %) and NOxThe figure of the relationship of purifying rate (%).
Figure 15 is the evaluation about heating reduction (the TPR:Temperature Programmed Reduction) method of being based on
Condition shows the figure of the relationship of time and temperature.
Figure 16 is the sample application for showing the exhaust gas purifying catalyst to embodiment 6 ' (solid line) and comparative example 6 ' (dotted line)
Temperature (DEG C) and H when heating reduction method2The figure of the relationship of consumption (TCD signal) (a.u.).
Specific embodiment
Hereinafter, detailed description of embodiments of the present invention.It is explained, the present invention is not limited to embodiment party below
Formula can carry out various modifications to implement in the range of the gist of the invention.
" exhaust gas purifying catalyst "
Exhaust gas purifying catalyst of the invention has the composition metal particle containing Rh and Pd, and is utilizing STEM-
When EDX analyzes the particle in exhaust gas purifying catalyst, Pd is 1.7 former relative to total average proportions of Rh and Pd
Sub- % or more 24.8 atom % or less.
About previous exhaust gas purifying catalyst, hold platinum family element (such as platinum (Pt), rhodium (Rh) and palladium (Pd) etc.)
In porous oxide carrier (such as aluminium oxide (Al2O3) etc.) and catalyst be widely known.
Wherein, about Rh, NOxReducing power it is high, as the catalyst metals for constituting exhaust gas purifying catalyst by
Think highly of.
But Rh is easily oxidised, NOxReducing power is possible to decline because of the oxidation.Accordingly, it is considered to arrive the oxygen of Rh
Change, makes the Rh in exhaust gas purifying catalyst containing excess quantity.But since Rh is the rare metal of very high price, from warp
From the viewpoint of Ji and environment, it is undesirable for being excessively used.
Therefore, the present inventor is conceived to the Pd weaker with the affinity of oxygen and has carried out wholwe-hearted research, as a result has developed
Containing Rh and Pd and Pd is below multiple as 1.7 atom % or more, 24.8 atom % relative to total average proportions of Rh and Pd
Close metal particle.
In the composition metal particle, since Pd inhibits the oxidation of Rh, the metallic state of Rh can be maintained for a long time.
Therefore, even if under the environmental condition that previous Rh is easily oxidised, such as under conditions ofs gas composition, pressure and temperature etc.,
The catalytic activity of Rh can also be maintained or be improved, and Rh is used with suitable amount.
The present inventors have additionally discovered that since Pd itself also has high exhaust gas purifying ability, as a result, containing Rh and
The composition metal particle of Pd can play the waste gas purification effect of collaboration due to both metallic elements.
Exhaust gas purifying catalyst of the invention also optionally has dust carrier, and composition metal particle is supported at
Dust carrier.
In the case where composition metal particle is supported at the dust carrier, due to the large specific surface area of dust carrier, because
This can increase the contact surface of exhaust gas Yu composition metal particle.The performance of exhaust gas purifying catalyst can as a result, improved.
< composition metal particle >
Composition metal particle contains Rh and Pd.
In the very small situation of partial size of composition metal particle, the NO of specific surface area increase thus RhxActive site quantity
With the NO of PdxActive site quantity increases, it is possible to can be improved the NO of exhaust gas purifying catalystxReducing power.
In addition, in the case where the partial size of composition metal particle appropriateness is big, it is possible to can fully play waste gas purification
The NO of catalystxDetergent power.
Therefore, the average grain diameter as multiple composition metal particles, is not particularly limited, but can enumerate more than 0nm, 1nm with
Upper or 2nm or more average grain diameter.In addition, the average grain diameter as multiple composition metal particles, is not particularly limited, but can enumerate
100nm or less, 70nm or less, 40nm or less, 10nm or less, 7nm or less, 5nm, 4nm or 3nm average grain diameter below.
Specifically, the partial size as composition metal particle, the preferably partial size of 1nm~10nm range, more preferable 2nm~
The partial size of 5nm range, the partial size of further preferred 2nm~3nm range.
By using the composition metal particle with such partial size as catalyst component, it can be achieved that Rh and Pd are with nanometer
Thus the composition metal particle that level coexists can play the effect for inhibiting Rh oxidation by Pd bring.Therefore, NO can be obtainedx
The exhaust gas purifying catalyst that purifying property improves.
It is explained, unless otherwise stated, in the present invention, " average grain diameter ", which refers to, is using scanning transmission electron microscopic
When the equipment such as mirror (STEM) are measured the equivalent circle diameter (Heywood diameter) of randomly selected 10 or more particles they
Measured value arithmetic mean of instantaneous value.
In the case where the Pd of composition metal particle is sufficiently large relative to total average proportions of Rh and Pd, become prone to
Play the effect for inhibiting Rh oxidation by Pd bring.In addition, can be sufficiently ensured the NO of Rh in the case where the ratio is not excessivex
The quantity of active site.
Particularly as total average proportions of the Pd relative to Rh and Pd of multiple composition metal particles, 1.7 can be enumerated
Atom % or more, 2 atom % or more, 3 atom % or more, 4 atom % or more and 5 atom % or more and/or 24.8 atom % with
Under, 20 atom % or less, 15 atom % or less, 13 atom % or less, 10 atom % or less, 8 atom % or less and 6 atom % with
Under average proportions.
In addition, " Pd in multiple composition metal particles relative to Rh and Pd total ratio respectively close to multiple multiple
Close total average proportions of the Pd in metal particle relative to Rh and Pd " refer in the presence of many average proportions having with the Pd
The composition metal particle of the ratio of close Pd.For example, the average proportions in the Pd are net to play exhaust gas of the invention significantly
In the case where changing ratio as the function and effect of catalyst, " there is many with the Pd's close with the average proportions of the Pd
The composition metal particle of ratio " means that the function and effect that can make exhaust gas purifying catalyst of the invention further increase.
It is related to this, as in terms of number benchmark 70%, 75%, 80%, 85%, 90% or 95% or more composition metal
Total ratio of the Pd of particle relative to Rh and Pd, is not particularly limited, but can enumerate the Pd phase in multiple composition metal particles
For total average proportions of Rh and Pd 20% or more, 30% or more, 40% or more and 50% or more and 190% with
Under, 180% or less, 170% or less and 160% average proportions below.
It as a result, can be for NOxPurification maintain enough Rh active site quantity while, effectively play and brought by Pd
Inhibit Rh oxidation effect.Therefore, NO can be obtainedxThe exhaust gas purifying catalyst that reducing power significantly improves.
It is explained, it should be apparent that keep the Pd in multiple composition metal particles each relative to total ratio of Rh and Pd
From the Pd in intentional separate multiple composition metal particles relative to Rh and Pd total average proportions (for example, multiple compound gold
Belong to Pd in particle relative to Rh and Pd total average proportions 1% hereinafter, or 400% with first-class) be usually easy.
It is explained, in the present invention, " total ratio of the Pd relative to Rh and Pd ", which refers in composition metal particle, to be contained
Ratio of some Pd atomicities relative to total atomicity of Rh atom and Pd atom.In the present invention " Pd is relative to Rh and Pd
Total ratio " be, for example, composition metal particle is analyzed by using optical means such as STEM-EDX and is calculated
Value.In addition, in the present invention, " total average proportions of the Pd relative to Rh and Pd " refer to through following calculated value:
The particle that such as 10 or more, 100 or more or 1000 or more are randomly choosed from exhaust gas purifying catalyst, utilizes STEM-
EDX etc. measures selected whole particle respectively, further selected from selected whole particles it is whole containing Rh and
The composition metal particle of Pd amounts to total ratio of the Pd relative to Rh and Pd of each composition metal particle, with the total divided by
The total number of selected whole composition metal particle.
In addition, unless otherwise stated, in the present invention, the ratio of " number benchmark " refers to the specific of exhaust gas purifying catalyst
Ratio of the number of the composition metal particle of composition relative to the number of whole composition metal particles.Waste gas purification of the invention is urged
The composition metal particle of agent has excellent exhaust gas purifying ability.It is understood, therefore, that in terms of number benchmark at least
For 70% or more composition metal particle in the case where preferably constituting, exhaust gas purifying catalyst of the invention is scaled its every ratio
Quality, than volume or specific surface area, further amounts of exhaust gas can be purified.
< dust carrier >
Composition metal particle of the invention is capable of loading and carrying in dust carrier.
The dust carrier for holding composition metal particle is not particularly limited, and can be the technical field in exhaust gas purifying catalyst
In be typically used as any metal oxide of dust carrier.
As such dust carrier, such as silica (SiO can be enumerated2), magnesia (MgO), zirconium oxide (ZrO2), oxygen
Change cerium (CeO2), aluminium oxide (Al2O3), titanium oxide (TiO2) and its solid solution or their combination etc..
Acid carrier (such as SiO2) and reduction NOxCatalyst metals compatibility it is good.Basic supports (such as MgO) with
Occlude NOxK or Ba compatibility it is good.ZrO2It can inhibit other powder at a high temperature of sintering occurs for other dust carriers like that
The sintering of last carrier, and by being combined with the Rh as catalyst metals, Steam Reforming reaction occurs to generate H2, can
Efficiently carry out NOxReduction.CeO2With under dilute atmosphere occlude oxygen, under dense atmosphere release oxygen OSC (Oxygen
Storage Capacity) characteristic, therefore it can be suitably used among three-way catalyst etc..Acid-base property pharmalyte (example
Such as Al2O3) due to that can be used for efficiently carrying out NO with high specific surface areaxOcclusion and reduction.TiO2It can send out
Wave the effect for inhibiting the sulfur poisoning of catalyst metals.
It will be appreciated that according to the characteristic of above-mentioned dust carrier, the waste gas purification energy of exhaust gas purifying catalyst of the invention
Power, particularly NOxDetergent power is possibly based on type, composition, combination and its ratio and/or amount of selected dust carrier
And it improves.
< Rh particle, CeO2And NOxOcclude the relationship > of reduction mechanism
(NOxOcclude reduction mechanism)
As described above, NOxOcclusion reduction mechanism is following mechanism: the NO in exhaust gas being oxidized to NO under dilute atmosphere2And it inhales
It stays, by the NO under stoichiometric ratio atmosphere and dense atmosphere2It is reduced into nitrogen (N2)。
(in NOxOcclude the Rh and NO when using Rh particle in reduction mechanismxBehavior)
As described above, Rh is to be easy to restore NOxMetal, on the other hand, be also easier to the metal being oxidized.In dilute gas
It is especially under atmosphere under dilute atmosphere of low temperature, Rh particle is the state being largely oxidized.It is exposed to by the Rh oxide fine particle
When under dense atmosphere, Rh oxide fine particle is reduced into Rh metal particle, thus it is believed that the NO of Rh is presentedxReducing power.That is, being
Make Rh that NO be presentedxReducing power, it is metal particle rather than the state of its oxide fine particle that Rh, which needs,.
(in NOxIt occludes and uses CeO in reduction mechanism2When CeO2And NOxBehavior)
CeO2Also have other than above-mentioned OSC characteristic and is easy to adsorb NO2Characteristic.Therefore, CeO2Under dilute atmosphere into
The occlusion of row oxygen and NO2Absorption, oxygen and NO are released under dense atmosphere2.It is explained, CeO2It is easy to adsorb NO2The reason of can recognize
To be due to CeO2With Al2O3It is comparably alkalinity.
The inventors discovered that the CeO under dense atmosphere2Inhibit the reduction of Rh oxide to NOxReduction it is insufficient, therefore,
About NOxOcclude reduction mechanism, Rh and CeO2Specific combination it is improper.
Thus, for example including Rh particle and CeO2Exhaust gas purifying catalyst in, about NOxReduction mechanism is occluded, due to
The NO that cannot will be occluded under dilute atmosphere under dense atmospherexIt fully restores, therefore a large amount of NOxIt is discharged to outside, is thus had
It can be it is observed that high NOxSpike (spike).It is explained, " NOxSpike " refers to when switching from dilute atmosphere to dense atmosphere, NOx
The phenomenon that increasing discharge rate moment.
Related to this, present inventor has performed wholwe-hearted researchs, and discovery is using micro- comprising the composition metal containing Rh and Pd
Grain and as dust carrier CeO2Exhaust gas purifying catalyst in the case where, can inhibit the generation of the problem.
It is not limited by any principle, but this is regarded as due in above-mentioned composition metal particle, since Pd can inhibit Rh
Oxidation, therefore under dense atmosphere especially under the dense atmosphere of low temperature, Rh oxide is easy to be reduced into Rh metal.
Therefore, comprising above-mentioned composition metal particle and contain CeO in exhaust gas purifying catalyst of the invention2Powder
In the case where carrier, NO can be improved under dilute atmospherexAdsorbance, while under dense atmosphere especially under the dense atmosphere of low temperature
Improve the catalytic activity of Rh.Therefore, contain the CeO as dust carrier in exhaust gas purifying catalyst of the invention2In the case where,
Exhaust gas can be improved and especially contain NOxExhaust gas detergent power.
Particularly, in the catalyst for purification of exhaust gas of the present invention, above-mentioned dust carrier is relative to the quality of dust carrier
Choosing is with more than 0 mass % and 40 mass % or less contain CeO2。
Dust carrier relative to dust carrier quality with larger proportion, for example to contain CeO more than 0 mass %2's
In the case of, above-mentioned NO can be improvedxAdsorption capacity.Therefore, the CeO that dust carrier contains2Quality of the amount relative to dust carrier
It can be for more than 0 mass %, 5 mass % or more, 10 mass % or more, 15 mass % or more, 20 mass % or more or 24 matter
Measure % or more.
Contain CeO with small percentage, for example with 40 mass % or less relative to the quality of dust carrier in dust carrier2's
In the case of, it can be adequately suppressed by CeO2The oxidation of caused Rh, and/or by under dense atmosphere from CeO2The oxygen of middle releasing causes
Reducing agent (such as the reducing agents such as hydrocarbon) consumption.Therefore, the CeO that dust carrier contains2Matter of the amount relative to dust carrier
Amount can be 40 mass % or less, 35 mass % or less or 29 mass % or less.
The loading amount for the composition metal particle that dust carrier is held is not particularly limited, but for example relative to dust carrier 100
Mass parts, more than typically 0.01 mass parts, more than 0.05 mass parts, more than 0.1 mass parts, more than 0.5 mass parts or 1
Loading amounts more than mass parts, and/or can be for 5 below the mass, 3 below the mass or 1 below the mass.
〈NOxOcclusion material >
Exhaust gas purifying catalyst of the invention optionally contains NOxOcclusion material.
NOxOcclusion material is not particularly limited, but can be basic matterial.As NOxOcclusion material can be enumerated: alkali metal and
Its salt, such as potassium (K) and potassium acetate etc.；Alkaline-earth metal and its salt, such as barium (Ba) and barium acetate etc.；And their combination.
" exhaust gas purifying method "
By waste gas purification the method comprise the steps that making under stoichiometric ratio atmosphere containing HC, CO and NOxExhaust gas with
Exhaust gas purifying catalyst contact of the invention, thus by HC and CO oxidation and by NOxOxidation is to be purified.
It is preferred that method of the invention to be applied to the internal combustion engine operated under stoichiometric ratio atmosphere.In stoichiometric ratio gas
Under atmosphere, as the HC and CO of reducing agent and as the NO of oxidantxIt is reacted, can be converted into theoretical equivalence ratio
H2O、CO2And N2。
The method for contacting exhaust gas under stoichiometric ratio atmosphere with exhaust gas purifying catalyst of the invention is any
The method of selection.
In addition, by waste gas purification the method comprise the steps that making under dilute atmosphere containing NOxExhaust gas and aforementioned present invention
Exhaust gas purifying catalyst contact, by the NO under dense atmospherexAlso purified originally.
It is preferred that method of the invention to be applied to the internal combustion engine operated under dilute atmosphere.This is because under dilute atmosphere, easily
In aoxidizing and removing HC and CO, on the other hand, it is not easy NOxReduction and removing, thus generate a large amount of NOx。
Make as under dilute atmosphere containing NOxThe method that is contacted with exhaust gas purifying catalyst of the invention of exhaust gas, can adopt
With optional method.
" manufacturing method of exhaust gas purifying catalyst "
Make exhaust gas purifying catalyst the method comprise the steps that contain Rh ion, Pd ion, reducing agent and protection
The solution of agent is heated to reflux, the process for thus generating composition metal particle；Wherein, above-mentioned Rh ion and above-mentioned Pd ion
Molar ratio is 70:30~99:1.
In general, the metal particle of nano-scale has the electronics energy structure different from block due to quantum size effect,
Thus the electro-optical characteristic dependent on particle size is shown.In turn, very big for specific surface area nano-scale
Metal particle expects that the catalyst as high activity plays a role.
The manufacturing method of metal particle about such nano-scale, following chemical reduction method is it is known that wrapping
The reducing agents such as alcohol are added in the mixed solution of salt containing each metallic element, and the mixed solution is heated on one side as needed
Deng by the ion for each metallic element for including in mixed solution while restoring on one side.
But in the case where restoring different metal ion chemistry, in general, the metallic element that oxidation-reduction potential is high
Ion be first reduced.Therefore, the high metallic element of oxidation-reduction potential is generated sometimes be present in the middle section of particle, oxidation
The low metallic element of reduction potential is present in the composition metal particle of the so-called nucleocapsid structure of surrounding composition metal particle.
Since in the composition metal particle of the nucleocapsid structure, element is not evenly distributed, therefore, it is possible to cannot fill
The ability for dividing ground to play catalyst.
It is mixed thus, for example patent document 1 is disclosed to by palladium chloride solution with rhodium chloride solution with molar ratio computing with 1:1
Made of composition metal aqueous colloidal dispersion irradiate laser beam so that the side of the element in composition metal colloidal particles being evenly distributed
Method.
In contrast to this, in the method for the invention, without using laser etc..It therefore, can be with less process number next life
At contain Rh and Pd and the uniform composition metal particle of Elemental redistribution.Therefore, it is possible to provide economic and environmental-friendly waste gas purification
The manufacturing method of catalyst.
It is not limited by any principle, but is believed that and can be generated from liquid phase without using laser etc. and contain Rh and Pd and member
The reason of composition metal particle that element is evenly distributed is, the oxidation-reduction potential of oxidation-reduction potential (0.758V) and Pd of Rh
(0.99V) is close value, and the reduction of each metal ion thus occurs at substantially the same time.
As to the time being heated to reflux containing Rh ion, Pd ion, reducing agent and protectant solution, not especially
It limits, but 0.5 hour or more, 1 hour or more, 1.5 hours or more and 3 hours or more and/or 48 hours or less, 24 can be enumerated
Hour or less, 12 hours or less and 6 hours time below.
In addition, method of the invention can optionally further comprise the process for carrying out generating composition metal particle
When or composition metal particle is supported at dust carrier after the process process.
Composition metal particle is supported at the sequence of dust carrier and method can be arbitrary sequence and method.It will be compound
Metal particle is supported at the sequence of dust carrier and method can be for example following sequence and method: to containing Rh ion,
After Pd ion, reducing agent and protectant solution are heated to reflux, dust carrier is added in the solution and is stirred, thus will
Composition metal particle is supported at dust carrier.Composition metal particle can be efficiently supported at dust carrier as a result,.
< Rh ion and Pd ion >
Contain Rh ion and Pd ion containing reducing agent and protectant solution.
As the raw material of Rh ion, be not particularly limited, but such as can enumerate the halide of salt and Rh of Rh and they
Combination.It as the raw material of Rh ion, can enumerate: inorganic salts of Rh, such as nitrate, phosphate and sulfate etc.；Rh's has
Machine hydrochlorate, such as oxalates and acetate etc.；Halide of Rh, such as fluoride, chloride, bromide and iodide etc.；With
And their combination.
About the raw material of Pd ion, the record of the raw material of above-mentioned Rh ion can refer to.
The concentration of Rh ion and Pd ion is not particularly limited.As the concentration of Rh ion and Pd ion, preferably theirs is total
Ion concentration is in the range of 0.01M~0.20M.
It as the molar ratio of Rh ion and Pd ion, is not particularly limited, but can be with the composition metal particle as target
In Rh it is related to the molar ratio of Pd, such as the molar ratio of 70:30~99:1, the molar ratio of 75:25~95:5 and 80 can be enumerated:
The molar ratio of 20~90:10.
As long as the molar ratio of Rh ion and Pd ion can manufacture the compound gold of above-mentioned exhaust gas purifying catalyst of the invention
Belong to particle to be just not particularly limited.Their molar ratio can be with the composition metal particle of the exhaust gas purifying catalyst of aforementioned present invention
Pd it is related to total average proportions of Pd relative to Rh.In such a case it is possible to consider the also archeus (example of these ions
Such as the solid solution easness of oxidation-reduction potential or each element) determine their molar ratio.
< reducing agent >
Contain reducing agent containing Rh ion, Pd ion and protectant solution.
Reducing agent can be used to restore Rh ion and Pd ion to generate composition metal particle.In addition, reducing agent can also
Optionally to have the function of as solvent.
As reducing agent, be not particularly limited, but preferably in normal conditions, have such as 95 DEG C or more, 100 DEG C or more,
The reducing agent of 110 DEG C or more or 120 DEG C or more of boiling point.
Since reducing agent has above-mentioned boiling point, Rh ion and Pd ion can be effectively restored, and produce Rh
With the uniform composition metal particle of Elemental redistribution of Pd.Therefore, as to contain Rh ion, Pd ion, reducing agent and protective agent
The temperature that is heated to reflux of solution, the temperature more than boiling point of preferably above-mentioned reducing agent.
It as reducing agent, is not particularly limited, but alcohol, sweet alcohols and aldehydes can be enumerated etc. and their combination.As reducing agent,
Alcohol, such as propyl alcohol, butanol and amylalcohol etc. can be enumerated；Glycol, such as ethylene glycol etc.；Aldehyde, such as valeral etc.；And their group
It closes.
As the amount of reducing agent, be not particularly limited, but total mole relative to Rh and Pd, can enumerate 1 times~
The mole of the mole of 100000 times of ranges, the mole of 1 times~50000 times ranges and 1 times~10000 times ranges.
< protective agent >
Solution containing Rh ion, Pd ion and reducing agent contains protective agent.
Protective agent can prevent the mutual excessive aggregation of composition metal particle, and divide composition metal particle moderately in the solution
It dissipates.Therefore, protective agent can be such that multiple composition metal particles of substantially uniform nano-scale moderately disperse in exhaust gas catalyst.
It as protective agent, is not particularly limited, but can enumerate: polyvinylpyrrolidone (PVP), polyvinylpyrrolidone K25
(PVP-K25), polyethyleneimine, polyallylamine, poly- (N- carboxymethyl) allylamine, poly- (bis- carboxymethyl of N, N-) allylamine and poly-
(N- carboxymethyl) aziridine etc. and their combination.Wherein, from the viewpoint of solubility height, preferably PVP.
It as protectant concentration, is not particularly limited as long as it can prevent the mutual aggregation of metal particle, but for example opposite
It in total mole of Rh and Pd, can enumerate: the mole of 1 times~1000 times ranges, the mole and 1 of 1 times~500 times ranges
Times~moles of 100 times of ranges.Here, protectant molar concentration refers in the case where protective agent is the polymer such as PVP
The mole of monomer unit.
< solvent >
Optionally contain solvent containing Rh ion, Pd ion, reducing agent and protectant solution.
Solvent is not particularly limited.As the boiling point of solvent, the boiling point of preferably higher than above-mentioned reducing agent.
The other > of <
About the constituent element of method of the invention, the record of above-mentioned exhaust gas purifying catalyst can refer to.
Referring to embodiments illustrated below, present invention be described in more detail, it will be clear that the scope of the present invention is not by these
Embodiment limits.
Embodiment
" embodiment 1 (liquid phase reduction) "
< includes the preparation > of the mixed solution of catalyst metals
Measure chlorination Pd (PdCl of the 0.078mmol as Pd ion2) and 5mL distilled water, by they 100mL burning
It is mixed in cup.In addition, measuring chlorination Rh (RhCl of the 1.477mmol as Rh ion3) and 5mL distilled water, by they
It is mixed in the beaker of 100mL.Solution A is prepared by mixing these Pd solution and Rh solution.
Measure 1- propyl alcohol of the 3.452g as protectant PVP-K25 and 150mL as reducing agent, by they
It is stirred in the separable flask of 500mL, PVP-K25 is dissolved, solution B is thus prepared.
Above-mentioned solution A is washed in the separable flask for being placed with the 500mL of above-mentioned solution B with the 1- propyl alcohol of 150mL, and
Stir the mixed solution.Then, the separable flask that will be placed with the 500mL of the mixed solution immerses 102 DEG C of oil bath, on one side into
Row N2It is bubbled, carries out being heated to reflux lasting 1.5 hours on one side.After being heated to reflux, above-mentioned mixed solution is cooled to room
Temperature.
< catalyst metals on the powdery support hold >
On the other hand, Al of the 80g as dust carrier is measured in the beaker of 500mL2O3-CeO2-ZrO2.In the 500mL
Beaker in add above-mentioned mixed solution and stir, evaporate solvent using hot bath.In addition, residual by what is obtained in drying oven
It after staying object drying over night, is crushed, is persistently burnt at 500 DEG C 2 hours in firing furnace.
The compacting > of < burned material
It from taking-up burned material in firing furnace and is fitted into the sack of CIP (isostatic cool pressing processing method), and carries out vacuum packet
Dress.With 1 ton/cm2It is suppressed, is sieved, and beaten with pestle to be granulated.It is urged using the particle as waste gas purification
The sample of agent.It is explained, it, can also be with grinding in the case where burned material aggregation when taking out burned material from firing furnace
Pestle is crushed burned material.
" embodiment 2 and 3 and comparative example 1 and 2 (liquid phase reduction) "
It is explained, other than the mole of change Rh and Pd, operates similarly with example 1 preparation embodiment 2 and 3
And the sample of the exhaust gas purifying catalyst of comparative example 1 and 2.
" comparative example 3 (impregnated with method) "
< includes the preparation > of the mixed solution of catalyst metals
Nitric acid Pd (8.2 mass %) of the 0.09g as Pd ion is measured, and measures nitric acid of the 1.57g as Rh ion
Rh (2.75 mass %).They are stirred in the beaker of 100mL together with the ion exchange water of 50mL, prepares solution C.
< catalyst metals on the powdery support hold >
On the other hand, Al of the 25g as dust carrier is measured2O3-CeO2-ZrO2.By the ion exchange water of itself and 150mL
It is stirred in the beaker of 500mL together, prepares solution D.
Above-mentioned solution C and solution D are mixed while being washed altogether with ion exchange water, prepare solution E.Steam the solution E
Hair is dried to solid.In addition, in drying oven by the drying solid it is drying over night after, held at 500 DEG C in firing furnace
Continuous firing 2 hours.
The compacting > of < burned material
It from taking-up burned material in firing furnace and is fitted into the sack of CIP (isostatic cool pressing processing method), and carries out vacuum packet
Dress.With 1 ton/cm2It is suppressed, is sieved, and beaten with pestle to be granulated.It is urged using the particle as waste gas purification
The sample of agent.It is explained, it, can also be with grinding in the case where burned material aggregation when taking out burned material from firing furnace
Pestle is crushed burned material.
The mole of Rh and Pd used in Examples 1 to 3 and comparative example 1~3 is shown in following table 1.
[table 1]
It is explained, " the 85:15 in table 1※" indicate in the sample of comparative example 3, Rh particle and Pd particle are deposited by oneself
, and Rh and Pd are contained with 85:15 with molar ratio computing.
< STEM-EDX analyzes >
Sample application STEM-EDX to the exhaust gas purifying catalyst prepared in Examples 1 to 3 and comparative example 1~3, by
This extracts multiple metal particles as measuring point from its STEM image, evaluates the composition and grain of the metal particle at each measuring point
Diameter.The result of Examples 1 to 3 and comparative example 1 and 3 is shown in Fig. 1~5.It is explained, in the sample of an example in office, sample
The average grain diameter of product is about 3nm.
By Fig. 1 (a) it is found that particle dispersedly exists in exhaust gas purifying catalyst.
By Fig. 1 (b) it is found that above-mentioned particle is the composition metal particle containing Rh and Pd.In addition, by Fig. 1 (b) it is found that this
The Pd in composition metal particles is relative to total ratio of Rh and Pd in the range of the 2 atom % of atom %~13.5 a bit.Separately
Outside it is found that by carrying out arithmetic average, Duo Gefu relative to total ratio of Rh and Pd to the Pd in each composition metal particle
It is 7.5 atom % that the Pd in metal particle, which is closed, relative to total average proportions of Rh and Pd.
Thus, it can be known that Pd in composition metal particle relative to Rh and Pd total ratio in multiple above-mentioned composition metals
Pd in particle relative to Rh and Pd total average proportions 27%~180% in the range of.
By Fig. 2 (a) it is found that particle dispersedly exists in exhaust gas purifying catalyst.
By Fig. 2 (b) it is found that above-mentioned particle is the composition metal particle containing Rh and Pd.In addition, by Fig. 2 (b) it is found that this
The Pd in composition metal particles is relative to total ratio of Rh and Pd in the range of the 12 atom % of atom %~31 a bit.In addition
It is found that by carrying out arithmetic average relative to total ratio of Rh and Pd to the Pd in each composition metal particle, it is multiple compound
Pd in metal particle is 16.5 atom % relative to total average proportions of Rh and Pd.
Thus, it can be known that Pd in composition metal particle relative to Rh and Pd total ratio in multiple above-mentioned composition metals
Pd in particle relative to Rh and Pd total average proportions 72.7%~188% in the range of.
By Fig. 3 (a) it is found that particle dispersedly exists in exhaust gas purifying catalyst.
By Fig. 3 (b) it is found that above-mentioned particle is the composition metal particle containing Rh and Pd.In addition, by Fig. 3 (b) it is found that this
The Pd in composition metal particles is relative to total ratio of Rh and Pd in the range of the 5.5 atom % of atom %~46.4 a bit.
In addition we know, multiple by carrying out arithmetic average relative to total ratio of Rh and Pd to the Pd in each composition metal particle
Pd in composition metal particle is 24.8 atom % relative to total average proportions of Rh and Pd.
Thus, it can be known that Pd in composition metal particle relative to Rh and Pd total ratio in multiple above-mentioned composition metals
Pd in particle relative to Rh and Pd total average proportions 22%~187% in the range of.
As described above, " Pd in composition metal particle relative to Rh and Pd total ratio in multiple above-mentioned compound gold
Belong to particle in Pd relative to Rh and Pd total average proportions about 20%~about 190% in the range of ", in other words,
Refer to the composition metal particle in the presence of many ratios with the Pd close with the average proportions of the Pd.
By Fig. 4 (a) it is found that particle dispersedly exists in exhaust gas purifying catalyst.By Fig. 4 (b) it is found that above-mentioned particle is
Only containing the metal particle of Rh.
By Fig. 5 (a) it is found that particle dispersedly exists in exhaust gas purifying catalyst.By Fig. 5 (b) it is found that above-mentioned particle is
Only containing Rh or only containing the metal particle of Pd.
" the evaluation A of catalyst "
About the sample of Examples 1 to 3 and the exhaust gas purifying catalyst of comparative example 1~3, evaluate as three-way catalyst
Performance, and the sample about Examples 1 to 3 and the exhaust gas purifying catalyst of comparative example 1, evaluation are used as NOxReduction is occluded to urge
The performance of agent.
Performance evaluation A > of the < as three-way catalyst
In the performance evaluation A as three-way catalyst, the catalyst test apparatus of using gas flow type.It is specific and
Speech, is made test gas flow through the catalyst test apparatus, is connect to measure with sample by using infrared measure (FT-IR)
The composition of test gas after touch.
It is explained, the quality of above-mentioned sample is 3g, and the test gas when evaluation of three-way catalyst to be constituted as follows:
NO:0.15%, O2: 0.70%, CO2: 10.00%, CO:0.65%, C3H6: 0.10%, H2O:3.00%, N2: surplus.
In addition, being 20L/ minutes by the flow rate set of test gas, the heating rate in evaluation is set as 20 DEG C/minute
Clock, and evaluated in the range of temperature is 100 DEG C~400 DEG C.The summary of the determination condition is shown in Fig. 6.
Specifically, the evaluation of three-way catalyst by carrying out as follows: temperature (DEG C) and NOxThe measurement of purifying rate (%)；
And total average proportions (atom %) and NO of the Pd relative to Rh and PdxThe measurement of 50% purification temperature (DEG C).By result
It is shown in Fig. 7 and Fig. 8.
(temperature (DEG C) and NOxThe measurement of purifying rate (%))
Fig. 7 is the temperature shown when evaluating the activity of the exhaust gas purifying catalyst of Examples 1 to 3 and comparative example 1~3
Spend (DEG C) and NOxThe figure of the relationship of purifying rate (%).Following (i)~(iii) as shown in Figure 7:
(i) in NOxSample in the range of purifying rate becomes about 0%~about 60%, with the comparative example 1 only with Rh particle
Temperature compare, with the composition metal particle containing Rh and Pd Examples 1 to 3 sample temperature be lower temperature.It is special
Not, in NOxIn the range of purifying rate (%) becomes about 0%~about 95%, compared with the temperature of the sample of comparative example 1, implement
The temperature of the sample of example 1 and 2 is lower temperature；
(ii) in NOxSample in the range of purifying rate becomes about 5%~95%, with the comparative example 2 only with Pd particle
Temperature compare, with the composition metal particle containing Rh and Pd Examples 1 to 3 sample temperature be lower temperature；
(iii) with the NO of the sample of the comparative example 3 containing Rh particle and Pd particlexPurifying rate is compared, and contains Rh's and Pd
The NO of the sample of the Examples 1 to 3 of composition metal particlexPurifying rate is at least higher in the range of about 260 DEG C~400 DEG C.
Therefore, by above-mentioned (i)~(iii) it is understood that the waste gas purification with the composition metal particle containing Rh and Pd is urged
The NO of agentxPurifying rate and the previous exhaust gas purifying catalyst containing Rh particle, Pd particle or Rh particle and Pd particle
NOxPurifying rate is higher activity compared to higher.
This is regarded as that the metallic state of Rh can be maintained for a long time because Pd inhibits the oxidation of Rh, thus maintain or
Improve NOxDetergent power.
(total average proportions (atom %) and NO of the Pd relative to Rh and PdxThe measurement of 50% purification temperature (DEG C))
Fig. 8 is shown to the Pd of the exhaust gas purifying catalyst of Examples 1 to 3 and comparative example 1 relative to the total of Rh and Pd
Average proportions (atom %) and NOxThe figure of the relationship of 50% purification temperature (DEG C).As shown in Figure 8, and the ratio containing Rh particle
Sample (Pd:0 atom %) compared with example 1 is compared, and the sample of the Examples 1 to 3 with the composition metal particle containing Rh and Pd exists
50% NO is realized under more low temperaturexPurifying rate.
In addition, indicating total average proportions (atom %) and NO of the Pd relative to Rh and Pdx50% purification temperature (DEG C)
Relationship curve be downwardly projecting curve.By the Fig. 8 it is found that NOxThere are compared with the past lower for 50% purification temperature
That is, there is the temperature range of exhaust gas purifying catalyst activation in temperature range.It can therefore be understood that Pd within the scope of this relative to Rh and
Total average proportions of Pd are to be suitable for purifying NOxTotal average proportions of the Pd relative to Rh and Pd.
In the NO of the sample of sample and comparative example 1 to Examples 1 to 3xWhen 50% purification temperature is compared, embodiment
The NO of 3 sample (Pd:24.8 atom %)x(294.8 DEG C) of the 50% purification temperature samples (Pd:0 atom %) lower than comparative example 1
50%NOxPurification temperature (296.9 DEG C).In addition, by the curve of Fig. 8 it is found that being averaged in Pd relative to the total of Rh and Pd
Ratio is NO more than 0 atom % and in the case where being less than about 27 atom %x50% purification temperature is lower than 296.9 DEG C, and then can manage
Solution exists within the scope of 294.8 DEG C or less of embodiment 3 of temperature and is best suited for purification NOxConjunction of the Pd relative to Rh and Pd
The average proportions of meter, according to the curve of Fig. 8, which is about 1.7 atom of atom %~24.8 %.
It is explained, as described above, if it is considered that total ratio of the Pd relative to Rh and Pd in composition metal particle
Pd of the example in multiple above-mentioned composition metal particles relative to Rh and Pd total average proportions about 20%~about 190%
In range, then it is appreciated that in the sample of Examples 1 to 3 there is the composition metal particle of many ratios with such Pd,
The ratio of the Pd with for purify NOxThe average proportions (the atom % of about 1.7 atom %~about 24.8) of effective Pd are close.Therefore
It is understood that since the Pd in multiple composition metal particles is micro- in multiple above-mentioned composition metals relative to total ratio of Rh and Pd
Pd in grain relative to Rh and Pd total average proportions about 20%~about 190% in the range of, therefore Examples 1 to 3
Sample NOxDetergent power further increases.
It is explained, the sample and NO of Examples 1 to 3 and comparative example 1~3 is shown in table 2 and Fig. 9x50% purification
The relationship of temperature (DEG C).
[table 2]
It is explained, " the 85:15 in table 2※" indicate that Rh particle and Pd particle exist by oneself in the sample of comparative example 3,
Rh and Pd are contained with 85:15 with molar ratio computing.
By table 2 and Fig. 9 it is found that NO with the sample of comparative example 2 and 3x50% purification temperature is compared, the sample of Examples 1 to 3
The NO of productx50% purification temperature is low, therefore the NO of the sample of Examples 1 to 3xDetergent power is higher.
Particularly, in the sample for the sample and the comparative example 3 for using impregnated with method for using the embodiment 2 of liquid phase reduction
In, the molar ratio of Rh and Pd in sample are roughly the same, but the NO of the sample of embodiment 2xLow 35 DEG C of 50% purification temperature or more.
This, which is believed that, is: in the sample of embodiment 2, the particle of catalyst metals contains Rh and Pd, and Rh and Pd
It is coexisted with nanometer level.I.e., it is believed that Pd inhibits the oxidation of Rh, maintains the metallic state of Rh, therefore Rh is activated, and implements
The NO of the sample of example 2x50% purification temperature is lower.
In addition, it can be said that composition metal since Pd itself also has high exhaust gas purifying ability, as a result containing Rh and Pd
Particle has played the waste gas purification effect of collaboration due to both metallic elements.
< is as NOxOcclude the performance evaluation A > of reducing catalyst
As NOxIn the performance evaluation for occluding reducing catalyst, the Al of 32g has been used2O3-ZrO2-TiO2As powder
Carrier, and use barium acetate as NO using in terms of 11 mass % by the quality of samplexOcclusion material uses in addition to this
Sample same as the sample of Examples 1 to 3 used in the performance evaluation of three-way catalyst and comparative example 1.Hereinafter, by this property
The sample (3g) that can be evaluated is referred to as the sample of embodiment 1 ', 2 ' and 3 ' and comparative example 1 '.
In addition, as NOxIn the performance evaluation for occluding reducing catalyst, the evaluating catalyst of gas flow type has been used
Device.Specifically, test gas is made to flow through the catalyst test apparatus, come by using infrared measure (FT-IR)
Measure the composition of the test gas after contacting with sample.
Test gas is made of dilute atmosphere and dense atmosphere, in the evaluation, 450 DEG C at a temperature of be alternately repeated 60 seconds it is dilute
Atmosphere and 6 seconds dense atmosphere.Show the composition of the test gas of dilute atmosphere and dense atmosphere in following Table 3, and in Figure 10 and
Evaluation result is shown in Figure 11.
[table 3]
In addition, being 20L/ minutes by the flow rate set of test gas, air speed (SV:Space Velocity) is set as
200000h-1.It is explained, air speed refers to the flow (volume/h) of test gas divided by value obtained from sample volume.
It is explained, " λ " of the intensity index as dilute atmosphere is defined as " oxidant equivalent/reducing agent equivalent ".For example,
Dense atmosphere, stoichiometric ratio atmosphere and dilute atmosphere can be indicated with λ < 1, λ=1 and λ > 1 respectively.
As shown in Figure 10, during 60 seconds dilute atmosphere, the occlusion that there are NO on sample is gradually saturated, NOxDischarge rate
(ppm) trend gradually increased.In addition, as shown in Figure 10, (during this period, due in test gas during 6 seconds dense atmosphere
In NO, therefore NO is not presentxDischarge rate die-offs) carry out so-called dense spike (rich spike) operation.Moreover, in 60 then
Second dilute atmosphere during, it is known that there are NO gradually to be occluded and trend that occlusion of the NO on sample is gradually saturated by sample.
It is explained, " dense spike " refers to the dense burning of very short time, thus can be by NOxThe NO that occlusion material is occludedxAlso
It is former.
Figure 11 is the enlarged drawing that with a portion of amplification about Figure 10.As shown in Figure 11, with the sample of comparative example 1 '
NOxDischarge rate is compared, the NO of the sample of embodiment 1 '~3 'xDischarge rate is less.
This is regarded as containing Rh and Pd due to the particle of catalyst metals, and Rh and Pd are coexisted with nanometer level, because
This Pd inhibits the oxidation of Rh, maintains the metallic state of Rh.Thus, it is believed that in the sample of embodiment 1 '~3 ', due to
Its NOxDetergent power is maintained or is improved, and can fully purify NOx, therefore NOxDischarge rate is reduced.
Relatively, it is believed that in the sample of comparative example 1 ', the NO of RhxDetergent power is deteriorated because of oxidation of Rh etc., and
And NO cannot be fully purified under dense atmospherex.Therefore, because the NO not being cleanedxBe expelled directly out, thus with embodiment 1 '
The NO of~3 ' samplexDischarge rate is compared, the NO of the sample of comparative example 1 'xDischarge rate increases.
It is explained, as shown in Figure 11, the peak of dense spike is reduced with the sequence of embodiment 1 '~3 '.This be regarded as because
The content of Pd in composition metal particle is higher, and the oxidation of Rh is more suppressed.
" embodiment 4~11 "
In the process that the catalyst metals of embodiment 2 are supported at dust carrier, using 16g by Al2O3And CeO2It constitutes
Dust carrier replace Al2O3-CeO2-ZrO2, and burned material is immersed in the barium acetate solution of 11 mass % will make
For NOxThe barium of occlusion material is supported at catalyst, in addition to this, in the same manner as the sample of the exhaust gas purifying catalyst of embodiment 2
Prepare the sample (grain shape, 1mm~1.7mm diameter, 3g) of the exhaust gas purifying catalyst of embodiment 4~11.It is explained, embodiment
The Al for the dust carrier that the sample of 4~11 exhaust gas purifying catalyst is included2O3And CeO2Mass ratio be respectively 100:0,
90:10,76:24,71:29,60:40,50:50,40:60 and 20:80.
" comparative example 4~11 "
In the process that the catalyst metals of comparative example 1 are supported at dust carrier, using 16g by Al2O3And CeO2It constitutes
Dust carrier replace Al2O3-CeO2-ZrO2, and burned material is immersed in the barium acetate solution of 11 mass % will make
For NOxThe barium of occlusion material is supported at catalyst, in addition to this, in the same manner as the sample of the exhaust gas purifying catalyst of comparative example 1
Prepare the sample (grain shape, 1mm~1.7mm diameter, 3g) of the exhaust gas purifying catalyst of comparative example 4~11.It is explained, comparative example
The Al for the dust carrier that the sample of 4~11 exhaust gas purifying catalyst is included2O3And CeO2Mass ratio be respectively 100:0,
90:10,76:24,71:29,60:40,50:50,40:60 and 20:80.
" the evaluation B of catalyst "
About the sample of embodiment 4~11 and the exhaust gas purifying catalyst of comparative example 4~11, evaluation is used as NOxIt occludes also
The performance of raw catalyst, in addition, for the sample of exhaust gas purifying catalyst, by applying heating reduction (TPR:Temperature
Programmed Reduction) method evaluates reduction temperature.
< is as NOxOcclude the performance evaluation B > of reducing catalyst
As NOxIn the performance evaluation B for occluding reducing catalyst, the catalyst test apparatus of using gas flow type.
Specifically, test gas is made to flow through the catalyst test apparatus, measured by using infrared measure (FT-IR) with
The composition of test gas after sample contact.
Test gas is made of dilute atmosphere and dense atmosphere, in the evaluation, 400 DEG C at a temperature of by 60 seconds dilute atmosphere and
6 seconds dense atmosphere is set as 1 circulation, repeats 5 circulations.In addition, being 20L/ minutes by the flow rate set of test gas, air speed is set
For 200000h-1.The composition of the test gas of dilute atmosphere and dense atmosphere is shown in following table 4, and in following table 5, Figure 13
With the result of evaluation is shown in Figure 14.
It is explained, the sample tool of the exhaust gas purifying catalyst of embodiment 4~11 and comparative example 4~11 is described in table 5
Details (the CeO in the ratio between form, Rh and Pd of particle, dust carrier of some dust carriers2Content) and NOxDischarge rate
Relative to NOxRatio (the NO of hold-upxDischarge rate/NOxHold-up).It is explained, in table 5, " NOxDischarge rate/NOxIt occludes
Amount " is 2~4 circulations extracted in above-mentioned 5 circulations, to their NOxDischarge rate/NOxHold-up carries out arithmetic average and obtains
The value arrived.
[table 4]
[table 5]
2 " the NO for illustrating table 5 referring to Fig.1xDischarge rate/NOxHold-up ".Figure 12 is shown as NOxOcclude reduction catalysts
In the performance evaluation B of agent, the NO that is made of 60 seconds dilute atmosphere and 6 seconds dense atmospherexOcclude the schematic diagram of reduction circulation.In Figure 12
In, dotted line indicates the content (certain) of the NO of dilute atmosphere before contacting with the sample of exhaust gas purifying catalyst；The region table of " S1 "
Show NO that the sample of the exhaust gas purifying catalyst under dilute atmosphere is occluded and/or absorptionxTotal amount (NOxHold-up)；" S2's "
Region (also referred to as NOxSpike) indicate the NO not being reduced being discharged from the sample of exhaust gas purifying catalyst under dense atmospherex's
Total amount (NOxDischarge rate).That is, above-mentioned " NOxDischarge rate/NOxHold-up " is equivalent to " S2/S1 " in Figure 12.
(as NOxOcclude the result of the performance evaluation B of reducing catalyst)
Figure 13 is shown in the sample for show the exhaust gas purifying catalyst of embodiment 4~11 (●) and comparative example 4~11 (■)
CeO in dust carrier out2Content (quality %) and NOxDischarge rate/NOxThe figure of the relationship of hold-up (a.u.).It is explained,
About the CeO in dust carrier2Content (quality %) and NOxDischarge rate/NOxThe relationship of hold-up (a.u.), is also referred to table
5。
As shown in Figure 13, the sample about the exhaust gas purifying catalyst of comparative example 4~11 (■), in dust carrier
CeO2Content rises, NOxDischarge rate/NOxThe value of hold-up linearly rises.This is regarded as due to the CeO in dust carrier2
Content is more, and the reduction of Rh oxide is more by CeO2Inhibition, and reducing agent (such as the reducing agents such as hydrocarbon) is disappeared by the oxygen
Consumption.
In addition, as shown in Figure 13, the sample of the exhaust gas purifying catalyst about embodiment 4~7 (●), when in dust carrier
CeO2When content is in the range more than 0 mass % and 29% or less, NOxDischarge rate/NOxThe value of hold-up is small and almost phase
Together.This is regarded as since in the composition metal particle containing Rh and Pd, Pd can inhibit the oxidation of Rh, therefore under dense atmosphere
It inhibits by CeO2The oxidation of caused Rh, the most of NO thus occludedxIt is cleaned.
It is explained, as shown in Figure 13, the sample of the exhaust gas purifying catalyst about embodiment 8~11 (●), with powder
CeO in last carrier2Content rises in the range of the 40 mass % of mass %~80, NOxDischarge rate/NOxThe value of hold-up is linear
Ground rises.But by Figure 13 it is understood that about NOxDischarge rate/NOxThe value of hold-up is being respectively compared embodiment 8 and comparative example
It 8, is all to implement in the case where embodiment 9 and comparative example 9, embodiment 10 and comparative example 10 and embodiment 11 and comparative example 11
The NO of examplexDischarge rate/NOxThe value of hold-up is smaller."NOxDischarge rate/NOxThe value of hold-up is small " indicate exhaust gas purifying catalyst
The most of NO occludedxIt is cleaned.
Figure 14 is the sample of the exhaust gas purifying catalyst about embodiment 4~11 (●) and comparative example 4~11 (■), is shown
CeO in dust carrier2Content (quality %) and NOxThe figure of the relationship of purifying rate (%).
As shown in Figure 14, comparing the CeO in these dust carriers2The exhaust gas of the identical embodiment of content and comparative example is net
In the case where changing catalyst (for example, combination of embodiment 7 and comparative example 7), the NO of the exhaust gas purifying catalyst of embodimentxPurification
Rate is higher than the NO of the exhaust gas purifying catalyst of comparative examplexPurifying rate.
In addition, by the curve of the embodiment of Figure 14 it is found that about the CeO in dust carrier2Content, more than 0 matter
It measures in % (embodiment 4) and the range of 40 mass % (embodiment 8) below, realizes extra high NOxPurifying rate.This is believed that
It is due to being combined with composition metal particle and CeO2Exhaust gas purifying catalyst in, improve NO under dilute atmospherexAdsorbance
While, the catalytic activity of Rh is improved under dense atmosphere.
The evaluation B > of < reduction temperature
The evaluation for carrying out reduction temperature, shows the result in Figure 16.
It is explained, specifically, carrying out reduction temperature by carrying out the process of following (1)~(6) in the order
Evaluation:
It (1) will be in the Sample introduction sample cell of 50mg exhaust gas purifying catalyst.
(2) according to gas generation apparatus, sample cell, desiccant and thermal conductivity detector (TCD) (TCD:Thermal
Conductivity Detector) sequence constitute evaluating apparatus.
(3) make by O2The gas that 10 volume % and 90 volume % of helium are constituted is with 30mL/ minutes from gas generation apparatus to sample
Quality control flows through, while so that the temperature of gas is warming up to 500 DEG C with 20 DEG C/min of heating rate.
(4) after the temperature of the gas reaches 500 DEG C, the constant temperature is maintained 10 minutes, thereafter by the temperature of the gas
Degree is cooled to 50 DEG C.
(5) gas being made of 100 volume % of Ar is flowed through from gas generation apparatus to sample cell.
(6) make by H21 volume % and Ar 99 the gas that constitutes of volume % with 30mL/ minutes from gas generation apparatus to sample
Quality control flows through, while so that the temperature of gas is warming up to 500 DEG C with 10 DEG C/min of heating rate.
It is explained, the effect of the desiccant of above-mentioned (2) is to capture the water for including in the gas by sample cell.Separately
Outside, the variation for the heat conductivity of gas that thermal conductivity detector (TCD) (TCD) measurement changes with gas componant, thus calculates the dense of gas
Degree.
In addition, the sample of embodiment 6 ' He comparative example 6 ' is respectively adopted in the sample of the exhaust gas purifying catalyst of above-mentioned (1).It is real
Applying example 6 ' and comparative example 6 ' is respectively the sample made in the same manner as embodiment 6 and comparative example 6, in addition to without that will be used as NOx
The barium of occlusion material be supported at the operation of carrier.
It is explained, about above-mentioned operation (1)~(6), a series of process is shown in FIG. 15.
(result of the evaluation B of reduction temperature)
Figure 16 be show to the exhaust gas purifying catalyst of embodiment 6 ' He comparative example 6 ' sample application heating reduction (TPR:
Temperature Programmed Reduction) method when temperature (DEG C) and H2The pass of consumption (TCD signal) (a.u.)
The figure of system.
In Figure 16, solid line indicates that the sample of the exhaust gas purifying catalyst of embodiment 6 ', dotted line indicate the useless of comparative example 6 '
The sample of gas cleaning catalyst.As shown in Figure 16, the H of the temperature of embodiment 6 '2The peak of consumption is about 115 DEG C, and is compared
The H of the temperature of example 6 '2The peak of consumption is about 170 DEG C.It can thus be appreciated that the compound gold of the exhaust gas purifying catalyst of embodiment 6 '
Belong to particle, particularly Rh therein is converted into metal from its oxide at lower temperatures.
This is regarded as since in the composition metal particle, Rh and Pd are coexisted with nanometer level, show significantly by
Pd bring inhibits the effect of Rh oxidation.
Although describing the preferred embodiments of the invention in detail, it will be appreciated by those skilled in the art that about this hair
Device, equipment and reagent used in bright etc. can be changed its manufacturer, grade and quality etc., without departing from right
The range of claim.
Claims (5)
1. exhaust gas purifying method, to make under dilute atmosphere containing NOxExhaust gas contacted with exhaust gas purifying catalyst, in dense atmosphere
It is lower by the NOxThe exhaust gas purifying method also purified originally, wherein
The exhaust gas purifying catalyst has composition metal particle and dust carrier containing Rh and Pd, and the composition metal is micro-
Grain is supported at the dust carrier, and the composition metal particle is obtained by liquid phase reduction,
When being analyzed using STEM-EDX the particle in the exhaust gas purifying catalyst, conjunction of the Pd relative to Rh and Pd
The average proportions of meter be 1.7 atom % or more, 24.8 atom % hereinafter,
Relative to the quality of the dust carrier, the dust carrier is with more than 5 mass % and 40 mass % or less contain CeO2,
The average proportions are by following calculated value: random selection 10 or more is micro- from exhaust gas purifying catalyst
Grain measures selected whole particles using STEM-EDX respectively, further selects whole from selected whole particles
The composition metal particle containing Rh and Pd, amount to the Pd of each composition metal particle relative to the total of Rh and Pd
Ratio, with the total divided by the total number of the selected whole composition metal particle.
2. exhaust gas purifying method described in claim 1, wherein relative to the quality of the dust carrier, the dust carrier
With more than 10 mass % and 40 mass % or less contain CeO2。
3. exhaust gas purifying method of any of claims 1 or 2, wherein in utilization STEM-EDX to the exhaust gas purifying catalyst
In particle when being analyzed, Pd is 2 atom % or more, 20 atom % or less relative to total average proportions of Rh and Pd.
4. exhaust gas purifying method of any of claims 1 or 2, wherein the exhaust gas purifying catalyst further contains NOx occlusion
Material.
5. exhaust gas purifying method as claimed in claim 3, wherein the exhaust gas purifying catalyst further contains NOx and occludes material
Material.
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| JP7020110B2 (en) * | 2017-12-26 | 2022-02-16 | トヨタ自動車株式会社 | Manufacturing method of catalyst for exhaust gas purification and catalyst for exhaust gas purification |
| CN108736030B (en) * | 2018-05-17 | 2020-12-25 | 福州大学 | Porous carbon-free catalyst for proton exchange membrane fuel cell and preparation method thereof |
| JP7099304B2 (en) * | 2018-12-19 | 2022-07-12 | トヨタ自動車株式会社 | Exhaust gas purification catalyst |
| JP7444762B2 (en) | 2020-07-28 | 2024-03-06 | トヨタ自動車株式会社 | Catalyst and exhaust gas purification device |
| CN114471046A (en) * | 2022-02-16 | 2022-05-13 | 福建龙净环保股份有限公司 | Flue gas purification device and MTO regeneration flue gas purification process system |
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Also Published As
| Publication number | Publication date |
|---|---|
| CN106040235A (en) | 2016-10-26 |
| JP6414043B2 (en) | 2018-10-31 |
| JP2016198759A (en) | 2016-12-01 |
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