CN104888845B - Platinum/cerium aluminum molecular screen catalyst for catalysis oxidation ammonia and preparation method thereof - Google Patents
Platinum/cerium aluminum molecular screen catalyst for catalysis oxidation ammonia and preparation method thereof Download PDFInfo
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- CN104888845B CN104888845B CN201510306885.2A CN201510306885A CN104888845B CN 104888845 B CN104888845 B CN 104888845B CN 201510306885 A CN201510306885 A CN 201510306885A CN 104888845 B CN104888845 B CN 104888845B
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 title claims abstract description 206
- 239000003054 catalyst Substances 0.000 title claims abstract description 178
- 229910052697 platinum Inorganic materials 0.000 title claims abstract description 100
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 89
- 229910052684 Cerium Inorganic materials 0.000 title claims abstract description 45
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 44
- 238000002360 preparation method Methods 0.000 title claims abstract description 29
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 28
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 22
- 230000003647 oxidation Effects 0.000 title claims abstract description 19
- 238000007254 oxidation reaction Methods 0.000 title claims abstract description 19
- 238000006555 catalytic reaction Methods 0.000 title claims abstract description 16
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 title abstract description 39
- 239000002131 composite material Substances 0.000 claims abstract description 61
- WLLURKMCNUGIRG-UHFFFAOYSA-N alumane;cerium Chemical compound [AlH3].[Ce] WLLURKMCNUGIRG-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000002808 molecular sieve Substances 0.000 claims abstract description 54
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 claims abstract description 52
- 229910052779 Neodymium Inorganic materials 0.000 claims abstract description 51
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 49
- 239000000919 ceramic Substances 0.000 claims abstract description 41
- 229910052878 cordierite Inorganic materials 0.000 claims abstract description 41
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 claims abstract description 41
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims abstract description 29
- 230000003197 catalytic effect Effects 0.000 claims abstract description 22
- PLDDOISOJJCEMH-UHFFFAOYSA-N neodymium(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Nd+3].[Nd+3] PLDDOISOJJCEMH-UHFFFAOYSA-N 0.000 claims abstract description 9
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910000420 cerium oxide Inorganic materials 0.000 claims abstract description 6
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 claims abstract description 6
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 60
- 239000000843 powder Substances 0.000 claims description 38
- 239000002002 slurry Substances 0.000 claims description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 13
- 229910001868 water Inorganic materials 0.000 claims description 11
- 239000004411 aluminium Substances 0.000 claims description 10
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 claims description 9
- 239000006255 coating slurry Substances 0.000 claims description 8
- NWAHZABTSDUXMJ-UHFFFAOYSA-N platinum(2+);dinitrate Chemical compound [Pt+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O NWAHZABTSDUXMJ-UHFFFAOYSA-N 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 claims description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 238000001704 evaporation Methods 0.000 claims description 5
- CFYGEIAZMVFFDE-UHFFFAOYSA-N neodymium(3+);trinitrate Chemical compound [Nd+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CFYGEIAZMVFFDE-UHFFFAOYSA-N 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 2
- ZDYCQQFBTFDFOK-UHFFFAOYSA-N acetic acid;platinum Chemical compound [Pt].CC(O)=O ZDYCQQFBTFDFOK-UHFFFAOYSA-N 0.000 claims description 2
- 239000008367 deionised water Substances 0.000 claims description 2
- 229910021641 deionized water Inorganic materials 0.000 claims description 2
- 238000000227 grinding Methods 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 2
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 claims 6
- GBHHXUXUWINXQG-UHFFFAOYSA-H [Pt](F)(F)(F)(F)(F)F.[Xe] Chemical compound [Pt](F)(F)(F)(F)(F)F.[Xe] GBHHXUXUWINXQG-UHFFFAOYSA-H 0.000 claims 1
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical compound [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 description 30
- 239000000243 solution Substances 0.000 description 28
- 238000006243 chemical reaction Methods 0.000 description 24
- 235000015165 citric acid Nutrition 0.000 description 20
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 18
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 13
- 238000000034 method Methods 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 9
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 9
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 239000011159 matrix material Substances 0.000 description 8
- 235000005979 Citrus limon Nutrition 0.000 description 6
- 238000001914 filtration Methods 0.000 description 6
- 238000009616 inductively coupled plasma Methods 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 239000007787 solid Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000003643 water by type Substances 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 5
- 238000000498 ball milling Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 4
- 239000004202 carbamide Substances 0.000 description 4
- 229910052763 palladium Inorganic materials 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 244000248349 Citrus limon Species 0.000 description 3
- 244000131522 Citrus pyriformis Species 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 230000007717 exclusion Effects 0.000 description 3
- 238000003801 milling Methods 0.000 description 3
- 230000010718 Oxidation Activity Effects 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003638 chemical reducing agent Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910010272 inorganic material Inorganic materials 0.000 description 2
- 239000011147 inorganic material Substances 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 150000003057 platinum Chemical class 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000000197 pyrolysis Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 210000002345 respiratory system Anatomy 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 239000010948 rhodium Substances 0.000 description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 2
- 229910052717 sulfur Inorganic materials 0.000 description 2
- 239000011593 sulfur Substances 0.000 description 2
- 208000024891 symptom Diseases 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- QGHDLJAZIIFENW-UHFFFAOYSA-N 4-[1,1,1,3,3,3-hexafluoro-2-(4-hydroxy-3-prop-2-enylphenyl)propan-2-yl]-2-prop-2-enylphenol Chemical group C1=C(CC=C)C(O)=CC=C1C(C(F)(F)F)(C(F)(F)F)C1=CC=C(O)C(CC=C)=C1 QGHDLJAZIIFENW-UHFFFAOYSA-N 0.000 description 1
- 206010013952 Dysphonia Diseases 0.000 description 1
- 206010014561 Emphysema Diseases 0.000 description 1
- 208000010473 Hoarseness Diseases 0.000 description 1
- 206010028813 Nausea Diseases 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000012876 carrier material Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 208000002173 dizziness Diseases 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- DNJIEGIFACGWOD-UHFFFAOYSA-N ethanethiol Chemical compound CCS DNJIEGIFACGWOD-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000003205 fragrance Substances 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 230000007794 irritation Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 230000008693 nausea Effects 0.000 description 1
- 239000001272 nitrous oxide Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- MUMZUERVLWJKNR-UHFFFAOYSA-N oxoplatinum Chemical group [Pt]=O MUMZUERVLWJKNR-UHFFFAOYSA-N 0.000 description 1
- 150000002927 oxygen compounds Chemical class 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000000638 stimulation Effects 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon atom Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)
Landscapes
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention provides a kind of platinum/cerium aluminum molecular screen catalyst for catalysis oxidation ammonia.The platinum/cerium aluminum molecular screen catalyst is using cordierite ceramic as carrier, and carrier surface is coated with catalyst layer, and the catalytic active center of residing catalyst layer is made up of noble metal platinum, cerium-aluminium composite oxide and neodymium modified molecular screen；The weight ratio of the cerium-aluminium composite oxide, neodymium modified molecular screen and noble metal platinum is 20~80:20~80:0.01~0.1；The weight ratio of cerium oxide and aluminum oxide is 1~3 in the cerium-aluminium composite oxide:1~5；The weight ratio of neodymia and molecular sieve is 1~10 in the neodymium modified molecular screen:90~100.Platinum of the present invention/cerium aluminum molecular screen catalyst can also realize that low temperature active window is wide under high air speed (SV), and catalytic activity is good, and selectivity is high, can effectively suppress N2O、NO、NO2The generation of secondary pollution.Present invention also offers the preparation method of the platinum/cerium aluminum molecular screen catalyst.
Description
Technical field
The invention belongs to catalyst technical field, it is related to a kind of catalyst for catalysis oxidation ammonia and its preparation side
Method, more particularly to a kind of platinum/cerium aluminium-molecular sieve catalyst for catalysis oxidation ammonia and preparation method thereof.
Background technology
Diesel engine is increasingly widely applied with its low oil consumption, high-power feature, but the height in cylinder of diesel engine
Warm high pressure can produce substantial amounts of nitrogen oxides, bring serious environmental problem.At present, China is substantially to use selective catalysis
Reduce (SCR) to handle the nitrogen oxides of diesel engine generation, wherein the most reducing agent of application is aqueous solution of urea, hydrolysis of urea
Generate ammonia.In order to reach tightened up NOx emission standard, following two methods are mainly used in the world：(1) spray more
Urea liquid, the shortcoming of this method is that unnecessary ammonia leakage can be caused；(2) it is this using the catalyst of absorption ammonia
The shortcoming of method is, when diesel vehicle carries out anxious accelerate, the exhaust temperature of discharge can be made drastically to raise, the ammonia aggravation of desorption
The leakage of ammonia, causes new secondary environmental pollution.
Ammonia is gas a kind of colourless and with intense irritation stench, and can be mutually dissolved in any proportion with water and
Highly volatile.It has stimulation and corrosiveness, resistance of the reduction human body to disease to human respiratory tract.People sucks in a short time
Substantial amounts of ammonia, in fact it could happen that shed tears, pharyngalgia, hoarseness, dizziness, nausea, the symptom such as uncomfortable in chest, weak, severe patient occurs
Pulmonary emphysema, while it also occur that respiratory tract symptom.Ammonia is included in odorant pollutant discharge by China, as field of Environment Protection
Item controlled, it is necessary to the discharge of strict control ammonia.
At present, the method for removing ammonia mainly has chemical absorption method, physisorphtion, catalystic pyrolysis, biofiltration process
And catalytic oxidation.Chemical absorption method and physisorphtion are although simple to operate, but need to regularly replace adsorbent, easily production
Raw secondary pollution.Catalystic pyrolysis needs to decompose at relatively high temperatures, and fixing equipment investment is larger.Biofiltration process,
Though secondary pollution is not produced, because of the low and difficult to realize industrialization of ammonia removal efficiency.
Catalytic oxidation is a kind of ideal Treatment process, is that under the atmosphere of catalyst and oxygen, ammonia is urged
Change is oxidized to free of contamination nitrogen and water., it is necessary to which catalyst low temperature performance well, can just make ammonia maximum in practical application
Nitrogen and water are converted into, the generation of nitrogen oxides accessory substance is reduced.Conventional catalyst system mainly has following a few classes：Metal oxygen
Compound type catalyst, Ion exchange-Size exclusion type catalyst and noble metal type catalyst.Although metal-oxide catalyst is selected
Selecting property is good and cheap, but its low temperature active is relatively low, and the conversion ratio at 250 DEG C is only 60%.Ion exchange-Size exclusion
Although type catalyst low temperature window is wide, nitrous oxide is also easy to produce at 250~300 DEG C, secondary pollution is caused.
Noble metal type catalyst be by platinum, palladium even load in the inorganic material such as aluminum oxide, have higher at 250~450 DEG C
Catalytic oxidation activity, preferable low temperature active window, the ammonia that will leak out aoxidized, shown in its reaction equation such as following formula (1).
4NH3+3O2→2N2+6H2O (1)
However, existing noble metal type catalyst is that, using aluminum oxide as carrier material, noble metal is distributed in oxygen mostly at present
Change on aluminium, cause noble metal catalyst while ammonia oxidation is carried out, easily cause N2O、NO、NO2Pollutant is produced, therefore sternly
The application of noble metal type catalyst in practice is limited again, and specific reaction is as shown in following formula (2)~(3).
4NH3+5O2→4NO+6H2O (2)
4NH3+7O2→4NO2+6H2O (3)
2NH3+2O2→N2O+3H2O (4)
CN 103476495A disclose a kind of ammoxidation catalyst and have used its waste gas purification apparatus and user
Method, using bilayer coating, lower floor is the inorganic material for having loaded noble metal, and upper strata is molecular sieve catalyst, although 250~
400 DEG C to NH3There is higher catalytic oxidation activity, but also generate higher concentration N simultaneously2O and NOx。
Therefore, in SCR (SCR) system of aqueous solution of urea as diesel engine reducing agent is used, exploitation
Go out low-temperature catalytic oxidation ammonia performance good, and can effectively suppress N2O、NO、NO2The noble metal type catalysis produced Deng pollutant
Agent is very urgent and necessary.
The content of the invention
Above-mentioned not enough there is provided one kind it is used for catalytic oxidation ammonia it is an object of the invention to overcome in the presence of prior art
The platinum of gas/cerium aluminium-molecular sieve catalyst and preparation method thereof.The platinum/cerium aluminium-molecular sieve catalyst is using cordierite ceramic as load
Body, is catalysis with noble metal platinum, cerium-aluminium composite oxide (Ce-Al composite oxides) and neodymium modified molecular screen (Nd/ZSM-5)
Activated centre, noble metal platinum is distributed on cerium-aluminium composite oxide and neodymium modified molecular screen, and adjusts its weight, is made
The platinum/cerium aluminium-molecular sieve catalyst can also realize that low temperature active window is wide under high air speed (SV), catalytic activity
Good, selectivity is high, can effectively suppress N2O、NO、NO2The generation of secondary pollution.
In order to realize foregoing invention purpose, the present invention provides following technical scheme：
Platinum/cerium aluminium-molecular sieve catalyst of the present invention for catalysis oxidation ammonia, using cordierite ceramic as carrier,
Carrier surface is coated with catalyst layer, it is characterised in that：The catalytic active center of the catalyst layer is by noble metal platinum, cerium-aluminium
Composite oxides and neodymium modified molecular screen composition；Cerium-the aluminium composite oxide, neodymium modified molecular screen and noble metal platinum are (with Pt
Meter) weight ratio be 20~80:20~80:0.01~0.1；The weight of cerium oxide and aluminum oxide in the cerium-aluminium composite oxide
Amount is than being 1~3:1~5；The weight ratio of neodymia and molecular sieve is 1~10 in the neodymium modified molecular screen:90~100.
The platinum of catalysis oxidation ammonia of the present invention/cerium aluminium-molecular sieve catalyst, noble metal platinum is with simple substance platinum and platinum oxide
Form exist.In the prior art, catalytic active center is generally used as using precious metal palladium, rhodium or gold.Wherein, precious metal palladium is to ammonia
The oxidation susceptibility of gas is not strong, it is impossible to by ammonia complete oxidation be nitrogen, cause to generate substantial amounts of oxynitrides, cause secondary dirt
Dye；And the sulfur resistance of palladium is very poor, easily causes sulfur poisoning.Noble Metal Rhodium does not have oxidation susceptibility, Er Qieqi to ammonia substantially
Price is somewhat expensive.Although gold has good oxidation susceptibility and selectivity at low temperature, ageing resistace is poor.Applicant passes through
Test of many times is found, noble metal platinum is distributed on cerium-aluminium composite oxide and neodymium modified molecular screen, is not only remarkably improved
The low-temperature catalytic activity of platinum/cerium aluminium-molecular sieve catalyst, and selectivity is high, and ammonia is being oxidized into N2While effectively press down
N is made2O、NO、NO2The generation of secondary pollution.Its main mechanism provides active sites for noble metal platinum, and ammonia is oxidized to
Oxynitrides or nitrogen, oxynitrides absorption there is provided secondary response, are converted into nitrogen in face over a molecular sieve, it is suppressed that
N2O、NO、NO2The generation of secondary pollution.
In catalyst layer, cerium-aluminium composite oxide makes ammonia react rapidly as the carrier of noble metal platinum；Neodymium is modified
The effect of molecular sieve serves not only as the carrier of noble metal, while can enter oxynitrides with the oxynitrides of adsorption reaction
Single step reaction generates nitrogen, suppresses N2O、NO、NO2The generation of secondary pollution.In the prior art, it is generally that noble metal is direct
It is distributed on non-modified molecular sieve, N can be caused2O、NO、NO2The generation of secondary pollution；The present invention is using neodymium to molecular sieve
It is modified, efficiently avoid the defect.
Preferably, the catalyst is counted in the coated weight of carrier surface according to the dry weight of catalyst layer for 120~180g/L
Calculate.That is catalyst pulp is after carrier surface is dried, is calcined, and the coated weight on its surface should reach every liter of cordierite ceramic load
Body surface face 120~180g of coating catalyst.When the dry weight of catalyst layer is less than 120g/L, ammonia oxidation is incomplete, does not reach height
Conversion ratio；When the dry weight of catalyst layer is more than 180g/L, the back pressure of diesel engine can be increased, the fuel economy of diesel engine is made
Into bad influence.It is further preferred that the dry weight of the catalyst layer is 150~170g/L.Most preferably preferably, the catalysis
The dry weight of oxidant layer is 155~165g/L.
Preferably, the molecular sieve is ZSM-5 molecular sieve.ZSM-5 molecular sieve basic structural unit is by eight five-membered rings
Composition, its crystal structure belongs to orthorhombic system, beneficial to the absorption of oxynitrides.
Applicant has found through many experiments, cerium-aluminium composite oxide, neodymium modified molecular screen and noble metal in catalyst layer
The weight ratio of platinum is to influence one of key factor of platinum/cerium aluminium-molecular sieve catalyst catalytic activity and selectivity.When cerium-aluminium is multiple
The weight ratio of oxide, neodymium modified molecular screen and noble metal platinum is closed 20~80:20~80:When in the range of 0.01~0.1,
Platinum/cerium aluminium-molecular sieve catalyst is preferable to ammonia catalytic activity and selectivity.It is further preferred that the cerium-aluminium composite oxygen
The weight ratio of compound, neodymium modified molecular screen and noble metal platinum is 40~70:30~60:0.04~0.06.Most preferably preferably, it is described
The weight ratio of cerium-aluminium composite oxide, neodymium modified molecular screen and noble metal platinum is 50:50:0.0441.More than preferably, can
So that the catalytic activity of platinum/cerium aluminium-molecular sieve catalyst and selectivity reach optimal, maximum journey while catalytic activity is improved
Degree ground suppresses N2O、NO、NO2The generation of secondary pollution.
The preparation method of platinum of the present invention/cerium aluminium-molecular sieve catalyst, it is characterised in that comprise the following steps：
(1) preparation of cerium-aluminium composite oxide
0.1~0.4g/ml aluminum nitrate solution and 0.1~0.4g/ml cerous nitrate solution are taken, is well mixed, is added to
In 0.1~0.3g/ml citric acid solution, 1~2h of stirring, evaporating water, in drying 20~24h at 100~120 DEG C, then
Roasting, obtains cerium-aluminium composite oxide；
(2) preparation of neodymium modified molecular screen
0.1~0.4g/ml neodymium nitrate solution is added in molecular sieve powder, at 100~120 DEG C dry 8~
10h；Then it is calcined, obtains neodymium modified molecular screen powder；
(3) preparation of slurry
Cerium-aluminium composite oxide, neodymium modified molecular screen powder, citric acid and platinum salt are added in deionized water, fully
Stirring, obtains catalyst pulp；
(4) ground slurry：Catalyst pulp is ground, until catalyst pulp particle is 2~5 μm；
(5) coating slurry：Using cordierite ceramic as carrier, cordierite ceramic is immersed into the catalyst pulp after grinding
In, submerge 3~5min；Then cordierite ceramic is taken out from catalyst pulp, blows remainder catalyst slurry in duct off, obtain
The cordierite ceramic of catalyst pulp is coated with to surface；
(6) dry and be calcined：By surface be coated with the cordierite ceramic of catalyst pulp at 100~120 DEG C dry 4~
6h, is then calcined, and is finally cooled to room temperature, obtains platinum/cerium aluminium-molecular sieve catalyst；Wherein catalyst pulp it is fired after
Coated weight is 120~180g/L.
Preparation method cost of the present invention is low, and small toxicity is simple to operate, is easily controlled, and obtained platinum/cerium aluminium-point
Sub- sieve catalyst low-temperature catalytic activity is good, can convert ammonia completely at 225 DEG C, and simultaneous selection is high, can effectively suppress
N2O、NO、NO2Secondary pollution generation.
Preferably, the volume ratio of aluminum nitrate solution and citric acid solution is 1 in the step (1):1~4.It is compound in cerium aluminium
In the preparation process of thing, the effect of citric acid is into the duct of cerium-aluminium composite oxide crystal, to increase its specific surface area.
When the volume ratio of aluminum nitrate solution and citric acid solution is less than 1:1, the cerium-aluminium composite oxide of preparation, which has, less compares surface
Product, is unfavorable for the reaction of ammonia.When the volume ratio of aluminum nitrate solution and citric acid solution is more than 1:4, excessive citric acid can enter
Enter in cerium-aluminium composite oxide crystal, because heat release is big during roasting, the tunnel collapse of a part can be caused, equally cause to compare table
Area reduces, and is unfavorable for the reaction of ammonia.
Preferably, it is roasted to 3~4h of roasting at 550~650 DEG C in the step (1).It is less than 3h between upon firing,
Citric acid incomplete combustion can be caused, while cerium-aluminium composite oxide stability is poor.Between upon firing be more than 4h, cause cerium-
Aluminium composite oxide is under the condition of high temperature for a long time, is caused cerium-aluminium composite oxide to sinter, is reduced its specific surface area.
Most preferably preferably, the roasting time in the step (1) is 3h.
Preferably, it is roasted to 3~4h of roasting at 550~650 DEG C in the step (2).Most preferably preferably, the step
Suddenly the roasting time in (2) is 3.5h.
Preferably, the platinum salt in the step (3) is platinum nitrate, chloroplatinic acid, acetic acid platinum, cyaniding platinum, platinic hydroxide, hexafluoro
Close the one or more in platinic acid xenon and ammonium chloroplatinate.
Preferably, the weight ratio of citric acid and cerium-aluminium composite oxide is 1 in the step (3):3~9.In catalyst
In the preparation process of slurry, the effect of citric acid is the pH value for adjusting slurry, changes slurry fluidity.When citric acid and cerium-aluminium
The weight ratio of composite oxides is 1:When 3~9, it can make slurry is more preferable must be coated in cordierite ceramic table by way of dipping
Face.Citric acid can generate carbon dioxide and water with oxygen reaction, will not remain in catalyst coat in roasting process.It is excellent
The weight ratio of citric acid and cerium-aluminium composite oxide is 1 in selection of land, the step (3):5~9.Most preferably preferably, the step
(3) the weight ratio of citric acid and cerium-aluminium composite oxide is 1 in:5.
Preferably, the roasting time in the step (6) is 2~3h.Obtained platinum/cerium aluminium-molecular sieve catalyst catalysis
Activity is good, and selectivity is high.Most preferably preferably, the roasting time is 2.5h.
The beneficial effects of the present invention are：
(1) platinum of the present invention/cerium aluminium-molecular sieve catalyst is using cordierite ceramic as carrier, with noble metal platinum, cerium-aluminium
Composite oxides and neodymium modified molecular screen are catalytic active center, and noble metal platinum is distributed in cerium-aluminium composite oxide and neodymium is modified
On molecular sieve, and by adjusting coated weight of the catalyst layer in carrier surface, and noble metal platinum, cerium-aluminium are multiple in catalyst layer
The weight of oxide and neodymium modified molecular screen is closed, makes the platinum/cerium aluminium-molecular sieve catalyst even in high air speed
(SV) it can also realize that low temperature active window is wide under, catalytic activity is good, can convert ammonia completely at 225 DEG C, simultaneous selection
Height, can effectively suppress N2O、NO、NO2The generation of secondary pollution.
(2) the preparation method cost of platinum of the present invention/cerium aluminium-molecular sieve catalyst is low, and small toxicity is simple to operate, holds
It is easy to control.
Brief description of the drawings
Fig. 1 is the NH of various ammonia VPO catalysts3Conversion ratio chart.
The N of the various ammonia VPO catalysts of Fig. 22O discharges concentration chart.
Fig. 3 is the NO of various ammonia VPO catalystsxDischarge concentration chart.
Embodiment
With reference to test example and embodiment, the present invention is described in further detail.But this should not be understood
Following embodiment is only limitted to for the scope of above-mentioned theme of the invention, it is all that this is belonged to based on the technology that present invention is realized
The scope of invention.
In embodiment of the present invention and comparative example, the cordierite ceramic used is diameter 25.4mm, high
25.4mm cylindrical cordierite ceramics.
Embodiment 1
(1) prepared by cerium-aluminium composite oxide
Take 0.4g/ml aluminum nitrate solution 261.0ml, 0.2g/ml cerous nitrate solution 236.7ml, and 0.2g/ml lemon
Lemon acid solution 758.7ml is well mixed；2h is stirred, reuses and 20h is dried at Rotary Evaporators evaporating water, 120 DEG C, finally put
Enter in Muffle furnace, from room temperature to 650 DEG C, and 3h is calcined at 650 DEG C, obtains cerium-aluminium composite oxide, the cerium-aluminium is multiple
The mass ratio for closing aluminum oxide and cerium oxide in oxide is 1:1.
(2) prepared by neodymium modified molecular screen
Take 0.2g/ml neodymium nitrate solution 29.5ml to be added in 47g ZSM-5 molecular sieve powder, place into baking oven,
10h is dried at 100 DEG C；It is subsequently placed into Muffle furnace, is calcined 3.5h at 600 DEG C, obtains neodymium modified molecular screen；The neodymium modified molecules
Neodymium element exists in the form of neodymia in sieve, and the mass ratio of neodymia and ZSM-5 molecular sieve is 6:94.
(3) preparation of catalyst pulp
Take 50g ceriums-aluminium composite oxide, 50g neodymium modified molecular screens powder, 10g citric acids, 1.588g platinum nitrate solutions
(metal platinum 2.78wt%) is added in 112.3ml deionized waters, is stirred, and obtains catalyst pulp.
(4) ball milling catalyst pulp：Catalyst pulp is ground by planetary ball mill, it is 2~5 μ to make pulp particle
M, obtains catalyst pulp；Wherein the rotating speed of planetary ball mill is 380~400 revs/min, and milling time is 1~1.5h.
(5) coating slurry：Cordierite ceramic matrix is immersed into polished catalyst pulp, submerges 3~5min；
Cordierite ceramic matrix is taken out from slurry, leftover slurry in duct is blown off, obtains being coated with the cordierite of catalyst pulp
The weightening of ceramics, wherein cordierite ceramic surface is 4.42g, and Pt contents are 2g/ft in final catalyst unit volume3。
(6) dry and be calcined：Surface is coated with the cordierite ceramic of catalyst pulp in 100 DEG C of dry 6h, Ran Houfang
Enter in Muffle furnace, 2.5h is calcined at 600 DEG C, obtain platinum/cerium aluminum molecular screen catalyst, i.e. Pt-1/CA-ZSM in accompanying drawing；Its
Coated weight after middle catalyst pulp is fired reaches 155~165g/L.
The catalyst pulp 20g for taking above-mentioned steps (4) to prepare is put into Muffle furnace, and 1~2h is calcined at 550~650 DEG C,
Room temperature is finally cooled to, is weighed, it is 46.74% as a result to obtain the solid content that powder quality is 9.348g, i.e. catalyst pulp.Then
Powder 10g is weighed again, and after the steps such as dissolving, precipitation, filtering, dissolving, noble metal platinum is carried out using inductively coupled plasma
The measure of content, as a result content of the noble metal platinum in powder be 0.0441 (platinum, g)/100 (powder, g).
From the foregoing, in platinum of the present invention/cerium aluminum molecular screen catalyst, cerium-aluminium composite oxide, neodymium are modified
The weight ratio of molecular sieve catalyst and noble metal platinum is 50:50:0.0441.
Embodiment 2
(1) prepared by cerium-aluminium composite oxide
Take 0.2g/ml aluminum nitrate solution 835.3ml, 0.3g/ml cerous nitrate solution 252.2ml, and 0.2g/ml lemon
Lemon acid solution 1213.6ml is well mixed；2h is stirred, reuses and 20h is dried at Rotary Evaporators evaporating water, 120 DEG C, finally
It is put into Muffle furnace, from room temperature to 650 DEG C, and 3h is calcined at 650 DEG C, obtains cerium-aluminium composite oxide, the cerium-aluminium
The mass ratio of aluminum oxide and cerium oxide is 4 in composite oxides:3.
(2) prepared by neodymium modified molecular screen
0.1g/ml neodymium nitrate solution 23.6ml is taken, is added in 28.8g ZSM-5 molecular sieve powder, places into baking oven
In, 8h is dried at 120 DEG C；It is subsequently placed into Muffle furnace, is calcined 3h at 650 DEG C, obtains neodymium modified molecular screen；The neodymium modified molecules
Neodymium element exists in the form of neodymia in sieve, and the mass ratio of neodymia and ZSM-5 molecular sieve is 4:96.
(3) preparation of catalyst pulp
Take 70g ceriums-aluminium composite oxide, 30g neodymium modified molecular screens powder, 10.0g citric acids, 2.054g platinum nitrate solutions
(metal platinum 2.78wt%) is added in 110.8ml deionized waters, is stirred, and obtains catalyst pulp.
(4) ball milling catalyst pulp：Catalyst pulp is ground by planetary ball mill, it is 2~5 μ to make pulp particle
M, obtains catalyst pulp；Wherein the rotating speed of planetary ball mill is 380~400 revs/min, and milling time is 1~1.5h.
(5) coating slurry：Cordierite ceramic matrix is immersed into polished catalyst pulp, submerges 3~5min；
Cordierite ceramic matrix is taken out from slurry, leftover slurry in duct is blown off, obtains being coated with the cordierite of catalyst pulp
The weightening of ceramics, wherein cordierite ceramic surface is 3.39g, and Pt contents are 2g/ft in final catalyst unit volume3。
(6) dry and be calcined：Surface is coated with the cordierite ceramic of catalyst pulp in 120 DEG C of dry 4h, Ran Houfang
Enter in Muffle furnace, 2h is calcined at 650 DEG C, obtain platinum/cerium aluminum molecular screen catalyst, i.e. Pt-2/CA-ZSM in accompanying drawing；Wherein
Coated weight after catalyst pulp is fired reaches 120~130g/L.
The catalyst pulp 20g for taking above-mentioned steps (4) to prepare is put into Muffle furnace, and 1~2h is calcined at 550~650 DEG C,
Room temperature is finally cooled to, is weighed, it is 47.03% as a result to obtain the solid content that powder quality is 9.506g, i.e. catalyst pulp.Then
Powder 10g is weighed again, and after the steps such as dissolving, precipitation, filtering, dissolving, noble metal platinum is carried out using inductively coupled plasma
The measure of content, as a result content of the noble metal platinum in powder be 0.0571 (platinum, g)/100 (powder, g).
From the foregoing, in platinum of the present invention/cerium aluminum molecular screen catalyst, cerium-aluminium composite oxide, neodymium are modified
The weight ratio of molecular sieve catalyst and noble metal platinum is 70:30:0.0571.
Embodiment 3
(1) prepared by cerium-aluminium composite oxide
Take 0.3g/ml aluminum nitrate solution 348.0ml, 0.4g/ml cerous nitrate solution 71.1ml, and 0.2g/ml lemon
Lemon acid solution 664.2ml is well mixed；1.5h is stirred, reuses and 24h is dried at Rotary Evaporators evaporating water, 100 DEG C, finally
It is put into Muffle furnace, from room temperature to 550 DEG C, and 4h is calcined at 550 DEG C, obtains cerium-aluminium composite oxide, the cerium-aluminium
The mass ratio of aluminum oxide and cerium oxide is 5 in composite oxides:3.
(2) prepared by neodymium modified molecular screen
0.2g/ml neodymium nitrate solution 11.8ml is taken, is added in 58.8g ZSM-5 molecular sieve powder, places into baking oven
In, 8h is dried at 120 DEG C；It is subsequently placed into Muffle furnace, is calcined 4h at 550 DEG C, obtains neodymium modified molecular screen；The neodymium modified molecules
Neodymium element exists in the form of neodymia in sieve, and the mass ratio of neodymia and ZSM-5 molecular sieve is 2:98.
(3) preparation of catalyst pulp
Take 40g ceriums-aluminium composite oxide, 60g neodymium modified molecular screens powder, 10g citric acids, 1.469g platinum nitrate solutions
(metal platinum 2.78wt%) is added in 115.2ml deionized waters, is stirred, and obtains catalyst pulp.
(4) ball milling catalyst pulp：Catalyst pulp is ground by planetary ball mill, it is 2~5 μ to make pulp particle
M, obtains catalyst pulp；Wherein the rotating speed of planetary ball mill is 380~400 revs/min, and milling time is 1~1.5h.
(5) coating slurry：Cordierite ceramic matrix is immersed into polished catalyst pulp, submerges 3~5min；
Cordierite ceramic matrix is taken out from slurry, leftover slurry in duct is blown off, obtains being coated with the cordierite of catalyst pulp
The weightening of ceramics, wherein cordierite ceramic surface is 4.82g, and Pt contents are 2g/ft in final catalyst unit volume3。
(6) dry and be calcined：Surface is coated with the cordierite ceramic of catalyst pulp in 120 DEG C of dry 4h, Ran Houfang
Enter in Muffle furnace, 3h is calcined at 550 DEG C, obtain platinum/cerium aluminum molecular screen catalyst, i.e. Pt-3/CA-ZSM in accompanying drawing；Wherein
Coated weight after catalyst pulp is fired reaches 170~180g/L.
The catalyst pulp 20g for taking above-mentioned steps (4) to prepare is put into Muffle furnace, and 1~2h is calcined at 550~650 DEG C,
Room temperature is finally cooled to, is weighed, it is 46.15% as a result to obtain the solid content that powder quality is 9.23g, i.e. catalyst pulp.Then
Powder 10g is weighed again, and after the steps such as dissolving, precipitation, filtering, dissolving, noble metal platinum is carried out using inductively coupled plasma
The measure of content, as a result content of the noble metal platinum in powder be 0.0408 (platinum, g)/100 (powder, g).
From the foregoing, in platinum of the present invention/cerium aluminum molecular screen catalyst, cerium-aluminium composite oxide, neodymium are modified
The weight ratio of molecular sieve catalyst and noble metal platinum is 40:60:0.0408.
Comparative example 1
Step (1) be the same as Example 1.
(2) preparation of catalyst pulp
100g ceriums-aluminium composite oxide, 10g citric acids, 1.588g platinum nitrate solutions (metal platinum 2.78wt%) is taken to add
Into 107.5ml deionized waters, stir, obtain catalyst pulp.
(3) step (4) in be the same as Example 1.
(4) coating slurry：Step (5) in be the same as Example 1, cordierite ceramic surface weightening is 4.31g, final catalyst
Pt contents are 2g/ft in unit volume3。
(5) dry and be calcined：Step (6) in be the same as Example 1, obtains the Pt-1/CA- in ammonia VPO catalysts, i.e. accompanying drawing
1。
The catalyst pulp 20g for taking step (4) to prepare is put into Muffle furnace, 1~2h is calcined at 550~650 DEG C, finally
Room temperature is cooled to, is weighed, it is 47.85% as a result to obtain the solid content that powder quality is 9.569g, i.e. catalyst pulp.Then claim again
Powder 10g is taken, after the steps such as dissolving, precipitation, filtering, dissolving, the measure of noble metal platinum content is carried out using ICP, as a result
Content of the noble metal platinum in powder is 0.0441 platinum, and g)/100 (powder, g).
From the foregoing, in platinum of the present invention/cerium aluminum molecular screen catalyst, cerium-aluminium composite oxide, neodymium are modified
The weight ratio of molecular sieve catalyst and noble metal platinum is 100:0:0.0441.
Comparative example 2
(1) prepared by cerium-aluminium composite oxide
Step (1) in be the same as Example 1.
(2) preparation of catalyst pulp
100g ceriums-aluminium composite oxide, 10g citric acids, 3.113g platinum nitrate solutions (metal platinum 2.78wt%) is taken to add
Into 104.6ml deionized waters, stir, obtain catalyst pulp.
(3) ball milling catalyst pulp：Step (4) in be the same as Example 1.
(4) coating slurry：Cordierite ceramic matrix is immersed into polished catalyst pulp, submerges 3~5min；
Cordierite ceramic matrix is taken out from slurry, leftover slurry in duct is blown off, obtains being coated with the cordierite of catalyst pulp
The weightening of ceramics, wherein cordierite ceramic surface is 2.18g, and Pt contents are 2g/ft in final catalyst unit volume3。
(6) dry and be calcined：Surface is coated with the cordierite ceramic of catalyst pulp in 100 DEG C of dry 6h, Ran Houfang
Enter in Muffle furnace, 2.5h is calcined at 600 DEG C, obtain the Pt-1/CA-2 in ammonia VPO catalysts, i.e. accompanying drawing；Wherein catalyst slurry
Coated weight after material is fired reaches 78~83g/L.
The catalyst pulp 20g for taking above-mentioned steps (4) to prepare is put into Muffle furnace, and 1~2h is calcined at 550~650 DEG C,
Room temperature is finally cooled to, is weighed, it is 48.16% as a result to obtain the solid content that powder quality is 9.632g, i.e. catalyst pulp.Then
Powder 10g is weighed again, and after the steps such as dissolving, precipitation, filtering, dissolving, noble metal platinum is carried out using inductively coupled plasma
The measure of content, as a result content of the noble metal platinum in powder be 0.0865 (platinum, g)/100 (powder, g).
From the foregoing, in platinum of the present invention/cerium aluminum molecular screen catalyst, cerium-aluminium composite oxide, neodymium are modified
The weight ratio of molecular sieve catalyst and noble metal platinum is 100:0:0.0865.
Comparative example 3
(1) prepared by cerium-aluminium composite oxide
Be the same as Example 1.
(2) preparation of catalyst pulp
50g ceriums-aluminium composite oxide, 50g ZSM-5 molecular sieves powder, 10g citric acids, 1.588g platinum nitrate solutions is taken to add
Enter into 113.1ml deionized waters, stir, obtain catalyst pulp.
(3) ball milling catalyst pulp：Step (4) in be the same as Example 1.
(4) coating slurry：The weightening of step (5) in be the same as Example 1, wherein cordierite ceramic surface is 4.35g, is finally urged
Pt contents are 2g/ft in agent unit volume3。
(5) dry and be calcined：Step (6) in be the same as Example 1, obtains ammonia VPO catalysts.Pt-1/CA- i.e. in accompanying drawing
3。
The catalyst pulp 20g for taking above-mentioned steps (3) to prepare is put into Muffle furnace, and 1~2h is calcined at 550~650 DEG C,
Room temperature is finally cooled to, is weighed, it is 46.62% as a result to obtain the solid content that powder quality is 9.324g, i.e. catalyst pulp.Then
Powder 10g is weighed again, and after the steps such as dissolving, precipitation, filtering, dissolving, noble metal platinum is carried out using inductively coupled plasma
The measure of content, as a result content of the noble metal platinum in powder be 0.0441 (platinum, g)/100 (powder, g).
From the foregoing, in platinum of the present invention/cerium aluminum molecular screen catalyst, cerium-aluminium composite oxide, molecular sieve
The weight ratio of catalyst and noble metal platinum is 50:50:0.0441.
Experimental example 1
Catalytic performance test is carried out to catalyst prepared by above-described embodiment 1~3 and comparative example 1~3.
By 200ppm ammonia (NH3), 10% oxygen (O2), 7% carbon dioxide (CO2), 8% vapor (H2O), remaining
For nitrogen (N2) mixed gas be passed through model gas experimental rig, reaction velocity is 150000~160000h-1, 200 DEG C,
Under 225 DEG C, 250 DEG C, 300 DEG C, 350 DEG C, 400 DEG C, 450 DEG C and 500 DEG C eight temperature conditionss, set point of temperature is being reached and dense
Degree gas circulation have passed through after 30 minutes after starting, and is measured in the case where the concentration of various gas componants is stable state.Respectively
NH at metered catalyst entrance and exit3、NO2、NO、N2O gas concentration, utilizes NH3Conversion ratio, NOx discharges concentration, N2O is arranged
Go out concentration this 3 indexs to evaluate catalyst (ASC) performance.
Wherein：NH3Conversion ratio %=(entrance NH3Concentration-outlet NH3Concentration)/(entrance NH3Concentration) × 100
(NOx discharges concentration ppm)=(outlet NO concentration ppm)+(outlet NO2Concentration ppm)
As a result as shown in table 1~3.
Fig. 1 is each catalyst to NH3Conversion ratio chart.Understand as shown in Figure 1, because prepared by the embodiment of the present invention 1~3
Catalyst comprising specific cerium-aluminium composite oxide and neodymium modified molecular screen (Nd/ZSM-5) powder as catalyst carrier,
I.e. noble metal platinum is distributed on cerium-aluminium composite oxide and neodymium modified molecular screen, in 225~500 DEG C of intervals to NH3Conversion ratio
Reach more than 90%, NH3Substantially completely it is converted.
And catalyst prepared by comparative example 1,2 causes NH due to the molecular sieve not being modified using neodymium3Conversion ratio relatively implement
Example 1~3 is decreased obviously, especially at 225 DEG C, to NH3Conversion ratio be only 70% or so, when catalyst coated weight is not enough
When, catalytic performance is substantially reduced.
Catalyst prepared by comparative example 3 causes NH due to not being modified using neodymium to molecular sieve3Conversion ratio is compared with embodiment
1~3 has decline, especially at 225 DEG C, to NH3Conversion ratio be less than 90%.
Fig. 2 is the N of each catalyst2O discharges concentration chart.As shown in Figure 2, the catalysis that prepared by the embodiment of the present invention 1~3
Agent, its exit N2O discharge concentration is very low, in the range of 200~500 DEG C, respectively less than 30ppm, especially 200~250
DEG C and 400~500 DEG C in the range of, respectively less than 15ppm.Show, platinum of the present invention/cerium aluminum molecular screen catalyst is right
NH3While with more than 90% conversion ratio, moreover it is possible to significantly inhibit harmful side product N2O generation.
By the N of comparative example 1~32O discharges concentration compared with embodiment 1~3, in the range of 200~500 DEG C, its N2O row
Except concentration has different degrees of raising, especially in the range of 300~400 DEG C, 5~15ppm or so has been respectively increased.
Fig. 3 is the NO of each catalystxExclude concentration chart.From the figure 3, it may be seen that catalysis prepared by the embodiment of the present invention 1~3
Agent, its exit NOxDischarge concentration it is very low, in the range of 200~500 DEG C, respectively less than 110ppm, especially 200~300
DEG C, respectively less than 20ppm.Show, platinum of the present invention/cerium aluminum molecular screen catalyst is to NH3With more than 90% conversion
While rate, moreover it is possible to significantly inhibit harmful side product NOxGeneration.This is due to NH3With NO or NO2Reaction, is generated nontoxic
N2And H2O is discharged.
By the NO of comparative example 1~3xConcentration is discharged compared with embodiment 1~3, in the range of 200~500 DEG C, its NOxRow
Except concentration has different degrees of raising, and it is obvious with the exclusion concentration difference of embodiment 1~3.
From Fig. 1~3, platinum of the present invention/cerium aluminium-molecular sieve catalyst can obtain higher than prior art
NH3Transformation efficiency, and N can be significantly inhibited2O accessory substances and adjoint NH3The NO that incomplete oxidation is causedxThe generation of accessory substance.Cause
This, platinum of the present invention/cerium aluminum molecular screen catalyst is widely portable to Diesel engine and leaks NH3Purification.
The NH of the platinum again prepared by embodiment 1/cerium aluminium-molecular sieve catalyst3Conversion ratio, N2O discharges concentration and NOxRow
Go out concentration compared with platinum/cerium aluminum molecular screen catalyst prepared by embodiment 2 and 3：In 200~500 DEG C, the NH of embodiment 13Conversion
Rate is higher than embodiment 2, is just slightly below embodiment 3.But the N of embodiment 12O、NOxDischarge concentration has not compared with Example 3,
With degree reduction；And the coated weight of embodiment 3 is bigger, cost increase influences Fuel Economy.To sum up, embodiment 1 with
Less advantage is in preferably effect, is preferred embodiment of the invention.
Claims (9)
1. a kind of platinum/cerium aluminium-molecular sieve catalyst for catalysis oxidation ammonia, using cordierite ceramic as carrier, carrier surface
It is coated with catalyst layer,
It is characterized in that：
The catalytic active center of the catalyst layer is made up of noble metal platinum, cerium-aluminium composite oxide and neodymium modified molecular screen；
The weight ratio of the cerium-aluminium composite oxide, neodymium modified molecular screen and noble metal platinum is 20~80:20~80:0.01~
0.1；
The weight ratio of cerium oxide and aluminum oxide is 1 ~ 3 in the cerium-aluminium composite oxide:1~5；
The weight ratio of neodymia and molecular sieve is 1~10 in the neodymium modified molecular screen:90~100.
2. platinum according to claim 1/cerium aluminium-molecular sieve catalyst, it is characterised in that：The catalyst is in carrier surface
Coated weight according to the dry weight of catalyst layer be 120~180g/L calculate.
3. platinum according to claim 1/cerium aluminium-molecular sieve catalyst, it is characterised in that：The molecular sieve is ZSM-5 points
Son sieve.
4. platinum according to claim 1/cerium aluminium-molecular sieve catalyst, it is characterised in that：Cerium-the aluminium composite oxide,
The weight ratio of neodymium modified molecular screen and noble metal platinum is 40~70:30~60:0.04~0.06.
5. it is a kind of such as the preparation method of any one of the claim 1 ~ 4 platinum/cerium aluminium-molecular sieve catalyst, it is characterised in that bag
Include following steps：
（1）The preparation of cerium-aluminium composite oxide
0.1 ~ 0.4g/ml aluminum nitrate solution and 0.1 ~ 0.4g/ml cerous nitrate solution are taken, is well mixed, it is added to 0.1 ~
In 0.3g/ml citric acid solution, 1~2h is stirred, then evaporating water is dried, be calcined, obtain cerium-aluminium composite oxide；
（2）The preparation of neodymium modified molecular screen
0.1 ~ 0.4g/ml neodymium nitrate solution is added in molecular sieve powder, is dried, is then calcined, obtains neodymium modified molecules
Sieve powder；
（3）The preparation of slurry
Cerium-aluminium composite oxide, neodymium modified molecular screen powder, citric acid and platinum source are added in deionized water, are sufficiently stirred for,
Obtain catalyst pulp；
The platinum source is in platinum nitrate, chloroplatinic acid, acetic acid platinum, cyaniding platinum, platinic hydroxide, xenon platinum hexafluoride and ammonium chloroplatinate
It is one or more of；
（4）Ground slurry：Catalyst pulp is ground, until catalyst pulp particle is 2~5 μm；
（5）Coating slurry：Using cordierite ceramic as carrier, cordierite ceramic is immersed into the catalyst pulp after grinding；So
Cordierite ceramic is taken out from catalyst pulp afterwards, remainder catalyst slurry in duct is blown off, obtains to surface and is coated with catalysis
The cordierite ceramic of agent slurry；
（6）Dry and be calcined：The cordierite ceramic that surface is coated with into catalyst pulp is dried, and is then calcined, last cold
But to room temperature, platinum/cerium aluminium-molecular sieve catalyst is obtained；Coated weight after wherein catalyst pulp is fired is 120~180g/
L。
6. preparation method according to claim 5, it is characterised in that：The step（1）Middle aluminum nitrate solution and citric acid
The volume ratio of solution is 1:1~4.
7. preparation method according to claim 5, it is characterised in that：The step（1）In be roasted at 550 ~ 650 DEG C
3~4h of lower roasting.
8. preparation method according to claim 5, it is characterised in that：The step（3）Middle citric acid and cerium-aluminium composite oxygen
The weight ratio of compound is 1:3~9.
9. preparation method according to claim 5, it is characterised in that：The step（6）In be roasted at 550 ~ 650 DEG C
2~3h of lower roasting.
Priority Applications (1)
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| CN109261200A (en) * | 2018-09-30 | 2019-01-25 | 无锡威孚环保催化剂有限公司 | NH_3 leakage catalyst and preparation method thereof for equivalent burn natural gas engines |
| CN110075907A (en) * | 2019-05-08 | 2019-08-02 | 中自环保科技股份有限公司 | A kind of ammoxidation catalyst and preparation method thereof for diesel car tail gas refining |
| CN112547115A (en) * | 2019-09-26 | 2021-03-26 | 中国石油化工股份有限公司 | Multi-effect catalyst for waste gas purification and waste gas purification method |
| CN113578374A (en) * | 2021-07-30 | 2021-11-02 | 芜湖美的厨卫电器制造有限公司 | Peculiar smell removing catalyst and preparation method and application thereof |
| CN115843275B (en) * | 2021-09-01 | 2024-02-06 | 宁波吉利罗佑发动机零部件有限公司 | Ammonia adsorption catalyst, preparation method and application thereof |
| CN116139923B (en) * | 2022-12-28 | 2024-04-05 | 济南大学 | Method for preparing Cu-based small-pore molecular sieve catalyst by gradient loading method, obtained product and application |
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