CN101015801A - Catalyst for catalytic cleaning of lean-burn engine tail gas and its preparing process - Google Patents
Catalyst for catalytic cleaning of lean-burn engine tail gas and its preparing process Download PDFInfo
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- CN101015801A CN101015801A CN 200710010360 CN200710010360A CN101015801A CN 101015801 A CN101015801 A CN 101015801A CN 200710010360 CN200710010360 CN 200710010360 CN 200710010360 A CN200710010360 A CN 200710010360A CN 101015801 A CN101015801 A CN 101015801A
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- 239000003054 catalyst Substances 0.000 title claims abstract description 81
- 238000000034 method Methods 0.000 title claims abstract description 19
- 230000003197 catalytic effect Effects 0.000 title claims description 29
- 230000008569 process Effects 0.000 title claims description 8
- 238000004140 cleaning Methods 0.000 title description 10
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 108
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000004408 titanium dioxide Substances 0.000 claims abstract description 49
- 239000011248 coating agent Substances 0.000 claims abstract description 47
- 238000000576 coating method Methods 0.000 claims abstract description 47
- 238000002360 preparation method Methods 0.000 claims abstract description 36
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 25
- RCFVMJKOEJFGTM-UHFFFAOYSA-N cerium zirconium Chemical compound [Zr].[Ce] RCFVMJKOEJFGTM-UHFFFAOYSA-N 0.000 claims abstract description 13
- 238000005470 impregnation Methods 0.000 claims abstract description 3
- 238000000746 purification Methods 0.000 claims abstract description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims abstract 5
- 238000011068 loading method Methods 0.000 claims abstract 2
- 239000000843 powder Substances 0.000 claims description 28
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 26
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 22
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 15
- 239000000243 solution Substances 0.000 claims description 14
- 239000002202 Polyethylene glycol Substances 0.000 claims description 11
- 229920001223 polyethylene glycol Polymers 0.000 claims description 11
- 239000011259 mixed solution Substances 0.000 claims description 10
- 238000003756 stirring Methods 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 101150003085 Pdcl gene Proteins 0.000 claims description 5
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 239000011247 coating layer Substances 0.000 claims description 2
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims 3
- YHWCPXVTRSHPNY-UHFFFAOYSA-N butan-1-olate;titanium(4+) Chemical compound [Ti+4].CCCC[O-].CCCC[O-].CCCC[O-].CCCC[O-] YHWCPXVTRSHPNY-UHFFFAOYSA-N 0.000 claims 2
- 229960000935 dehydrated alcohol Drugs 0.000 claims 2
- 229910002492 Ce(NO3)3·6H2O Inorganic materials 0.000 claims 1
- 229960004756 ethanol Drugs 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 claims 1
- 239000007787 solid Substances 0.000 claims 1
- 229910052726 zirconium Inorganic materials 0.000 claims 1
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 abstract description 18
- 239000007789 gas Substances 0.000 abstract description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 10
- 229910052760 oxygen Inorganic materials 0.000 abstract description 10
- 239000001301 oxygen Substances 0.000 abstract description 9
- 230000000694 effects Effects 0.000 abstract description 8
- 230000008901 benefit Effects 0.000 abstract description 6
- 238000005516 engineering process Methods 0.000 abstract description 3
- QWDUNBOWGVRUCG-UHFFFAOYSA-N n-(4-chloro-2-nitrophenyl)acetamide Chemical compound CC(=O)NC1=CC=C(Cl)C=C1[N+]([O-])=O QWDUNBOWGVRUCG-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052684 Cerium Inorganic materials 0.000 description 20
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 20
- 238000009413 insulation Methods 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 11
- 238000006722 reduction reaction Methods 0.000 description 10
- 230000009467 reduction Effects 0.000 description 8
- FPCJKVGGYOAWIZ-UHFFFAOYSA-N butan-1-ol;titanium Chemical compound [Ti].CCCCO.CCCCO.CCCCO.CCCCO FPCJKVGGYOAWIZ-UHFFFAOYSA-N 0.000 description 7
- 238000010531 catalytic reduction reaction Methods 0.000 description 7
- 238000001035 drying Methods 0.000 description 7
- 238000006555 catalytic reaction Methods 0.000 description 6
- 239000003638 chemical reducing agent Substances 0.000 description 6
- 239000006185 dispersion Substances 0.000 description 6
- OERNJTNJEZOPIA-UHFFFAOYSA-N zirconium nitrate Chemical compound [Zr+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O OERNJTNJEZOPIA-UHFFFAOYSA-N 0.000 description 6
- 239000001257 hydrogen Substances 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 5
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 229940043237 diethanolamine Drugs 0.000 description 4
- 235000019441 ethanol Nutrition 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- 239000010970 precious metal Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 238000003980 solgel method Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 239000002912 waste gas Substances 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 2
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 230000002829 reductive effect Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000001802 infusion Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000001282 iso-butane Substances 0.000 description 1
- 235000013847 iso-butane Nutrition 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000002808 molecular sieve Substances 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 231100000572 poisoning Toxicity 0.000 description 1
- 230000000607 poisoning effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Landscapes
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
汽车尾气净化技术领域中的一种催化净化贫燃发动机尾气的催化剂及其制备方法，包括载体和催化活性组分，其特征在于：催化剂是以γ－Al2O3为载体，并在载体表面附着二氧化钛和铈锆混合氧化物涂层，在该多组分氧化物载体上采用浸渍法负载活性组分钯，其中，以载体的重量为基准，TiO2的含量为14.0－20.0wt.％；CeZrO的含量为3.0～6.0wt.％；以催化剂的重量为基准，催化剂活性组分钯的含量为0.1～1.0wt.％；制备步骤为：二氧化钛溶胶的制备；氧化铝表面二氧化钛涂层的制备；铈锆溶胶的制备；附着二氧化钛涂层的载体上铈锆氧化物的负载；引入活性组分钯。优点：该催化剂于过量氧存在条件下，在较低温度范围，具有较高的去除氮氧化物活性；制备工艺简单。A catalyst for catalytically purifying lean-burn engine exhaust gas and a preparation method thereof in the technical field of automobile exhaust purification technology, including a carrier and a catalytically active component, characterized in that the catalyst uses γ-Al 2 O 3 as a carrier, and on the surface of the carrier A coating of titanium dioxide and cerium-zirconium mixed oxide is attached, and the active component palladium is loaded on the multi-component oxide carrier by impregnation method, wherein, based on the weight of the carrier, the content of TiO2 is 14.0-20.0wt.%. The content of CeZrO is 3.0-6.0wt.%; based on the weight of the catalyst, the content of palladium, the active component of the catalyst, is 0.1-1.0wt.%. The preparation steps are: preparation of titania sol; preparation of titania coating on the surface of alumina ; Preparation of cerium-zirconium sol; Loading of cerium-zirconium oxide on a carrier with titania coating; Introduction of active component palladium. Advantages: the catalyst has high nitrogen oxide removal activity in a relatively low temperature range under the condition of excess oxygen; the preparation process is simple.
Description
Technical field
The present invention relates to a kind of Catalysts and its preparation method of catalytic cleaning of lean-burn engine tail gas, this catalyst is carrier with the aluminium oxide, at its area load titanium dioxide and cerium Zr mixed oxide, precious metal palladium belongs to the catalytic cleaning of car tail gas technical field as active component.
Background technology
Along with energy savings and protection environment cry grow to even greater heights, poor burn engine reduces greenhouse gases CO because of improving the economy that fuel utilizes
2Discharging, and be subjected to more and more widely paying attention to.Poor burn engine comprises poor combustion petrol engine and Diesel engine, and this kind engine is controlled at the petrol engine of operating under the stoichiometric proportion condition with tradition and compares, the reproducibility waste gas component carbon monoxide (CO) in the tail gas, hydrogen (H
2) and imperfect combustion hydrocarbon (HC) content less, include excessive oxidation component oxygen (O in the corresponding waste gas
2) and nitrogen oxide (NO
x), wherein the concentration of oxygen is generally 3-15%.
Because the tail gas that poor burn engine is discharged contains a large amount of oxygen, now commercial three-way catalyst can not be catalytically conveted to nitrogen effectively with the nitrogen oxide that is wherein contained.Round the catalytic purification of exhaust of lean-burn automotive, carried out a large amount of research.At present, remove NO in the exhaust of lean-burn automotive
xMethod mainly be: NO
xDirect decomposition, poor combustion NO
xAbsorption, reduction technique and NO
xThe selection catalytic reduction.Wherein select Reduction of NO
xBe proved to be a kind of very potential NO that is used for removing under the excess oxygen
xMethod.
Poor burn engine is different with the petrol engine situation of operating under the stoichiometric proportion condition, for this type of catalyst, the catalytic reduction that can observe nitrogen oxide has a suitable temperature range, before this temperature range, transformation efficiency of the oxides of nitrogen increases along with the rising of EGT, under a certain temperature, conversion ratio reaches maximum, and conversion ratio reduces gradually under higher temperature.
When being used to select the reducing agent of catalyzing and reducing nitrogen oxides certain, when promptly selecting hydro carbons remaining in the waste gas to be reducing agent, the position of temperature window and width depend on the prescription and the preparation method of catalyst.Wherein typical example has:
(1) people such as Zhiming Liu is at Appl.Catal.B 2004, " the bimetallic Co-In/Al that delivers on the 48:37-48
2O
3Active facilitation with selecting reduction of NO by propylene " (Activity enhancement ofbimetallic Co-In/Al
2O
3Catalyst for the selective reduction of NO by propene) in the literary composition, its scheme is: prepare Co/Al by sol-gel process
2O
3Catalyst, and add In, Sn and Ag promotes its catalytic activity.Under excess oxygen, be reducing agent with the propylene, check the selecting catalytic performance energy of these catalyst to NO.Advantage: (1) Co-In/Al
2O
3The ability of the removal NO that the catalyst performance is good; (2) SO
2And H
2O is very little to the inhibitory action of Reduction of NO.Shortcoming: the reaction temperature of catalyst is higher, and the conversion ratio of NO just reaches maximum at 400 ℃.
(2) people such as Thomas Holam is at Appl.Catal.B.2004, and that delivers on the 48:95-100 " uses the hydrocarbon reductive NO on the diplopore System Catalyst
x" (Continuous lean NO
xReduction withhydrocarbons over dual pore system catalysts) in the literary composition, its scheme is: CoFER and HZSM-5 diplopore System Catalyst with the mechanical mixing preparation are applied to NO under the lean-burn condition
xCatalytic reduction, iso-butane is a reducing agent.Advantage: at moderate temperature scope catalyst to NO
xCatalytic reduction ability is preferably arranged.Shortcoming: the catalytic reaction temperature is higher, and because its carrier belongs to molecular sieve, anti-steam deactivation is relatively poor.
(3) people such as Erol Seker is at J.Catal.2000, deliver on the 194:4-13 " research prepares Pt/ aluminium oxide catalyst selective reduction NO with sol-gel process
xActivity and N
2Selectivity " (Activity and N
2Selectivity of sol-gel prepared Pt/alumina catalysts for selective NO
xReduction) in the literary composition, its scheme is: by preparing Pt/Al with a step sol-gel process
2O
3Catalyst is also used NO
xCatalytic reaction check its catalytic activity and N
2Selectivity.Advantage: (1) catalyst shows excellent NO
xConversion ratio and higher N
2Selectivity; (2) catalyst performance better low temperature activity; (3) the sulfur poisoning-resistant ability of catalyst is higher.Shortcoming: in (1) catalytic reduction product N is arranged
2O generates; (2) active temperature windows is narrower.
(4) people such as Gongshin Qi is at J.Catal.2006, in " catalyst based the going up of Pd selected catalyzing and reducing nitrogen oxides with hydrogen " (Selective catalytic reduction of nitric oxidewith hydrogen over Pd-based catalysts) literary composition of delivering on the 237:381-392, its scheme is: under excess oxygen, with hydrogen is reducing agent, selects Reduction of NO on Pd is catalyst based.Compared TiO
2-Al
2O
3, Al
2O
3And TiO
2As the influence of carrier, and add V to catalytic reaction
2O
5Influence to catalyst performance.Advantage:
(1) TiO
2-Al
2O
3The mixed oxide carrier shows than single carrier excellent catalytic performance: (2) Pd-V
2O
5/ TiO
2-Al
2O
3Catalyst shows good low-temperature catalyzed performance, and reaction temperature window broad.Shortcoming: reducing agent is a hydrogen, can not make full use of exhaust gas component.
Summary of the invention
Purpose of the present invention and task will overcome existing catalyst and exist: (1) is good Reduction of NO at a lower temperature
x(2) the narrow deficiency of active temperature windows, and a kind of low-temperature catalytic activity height that has is provided, the operating temperature window is wide, is applicable to the Catalysts and its preparation method of NOx in the catalytic cleaning of lean-burn engine tail gas, special proposition technical solution of the present invention.
The catalyst of a kind of catalytic cleaning of lean-burn engine tail gas proposed by the invention comprises carrier and catalytic active component, it is characterized in that: catalyst is with γ-Al
2O
3Be carrier, and on carrier, adhere to titanium dioxide and cerium Zr mixed oxide coating, on this multi-component oxide carrier, adopt infusion process load active component palladium, wherein, a) γ-Al
2O
3Be pressed powder; B) weight with carrier is benchmark, TiO
2Content be 14.0～20.0wt.%; The content of CeZrO is 3.0～6.0wt.%; C) weight with catalyst is benchmark, and the content of catalyst activity component palladium is 0.1～1.0wt.%; D) expression formula of catalyst is Pd/CeZrO/TiO
2/ Al
2O
3
The Preparation of catalysts method of a kind of catalytic cleaning of lean-burn engine tail gas proposed by the invention is characterized in that preparation process is as follows:
The first step, the preparation of TiO 2 sol
With the volume ratio is V
Butyl titanate: V
Absolute ethyl alcohol=1: 2～1: 6 ratio, butyl titanate is added in the absolute ethyl alcohol, then adding its concentration in solution of diethanol amine is 4.8% (volume ratio), magnetic agitation 2h at room temperature, slowly dripping its volume ratio then is V
Ethanol: V
Water=10: 1 the absolute ethyl alcohol and the mixed solution of water, adding molecular weight then and be its concentration in colloidal sol of polyethylene glycol of 2000 is 5～20g/L, ultrasonic again dispersion 10～20min obtains transparent TiO
2Colloidal sol;
Second step, the preparation of alumina powder surface titanium dioxide coating
Alumina powder is immersed this TiO
2In the colloidal sol, treat to take out behind 2～10min, at first, dry 6-10h under 100-120 ℃; Subsequently, sample is immersed TiO again
2Colloidal sol repeats 2-5 time repeatedly; Then, the speed with 120 ℃/h in Muffle furnace is warming up to 400-600 ℃, insulation 2-3h; At last, reduce to room temperature;
The 3rd step, the preparation of cerium zirconium colloidal sol
Be M in molar ratio
Ce: M
Zr=67: 33 ratio is with Ce (NO
3)
36H
2O and Zr (NO
3)
45H
2O is mixed with mixed aqueous solution, and adding molecular weight then and be its concentration of polyethylene glycol of 2000 is 1.5～3.0g/L, and mixed solution is stirred in 60～80 ℃ of lower magnetic forces, slowly drips the 0.1mol/L citric acid in the process that stirs, and obtains white emulsus CeZrO colloidal sol;
The 4th step, the load of adhering to cerium Zr mixed oxide on the carrier of coating of titanium dioxide
The alumina powder that will adhere to coating of titanium dioxide immerses in the CeZrO colloidal sol, treats to take out behind 5～15min, then, at 100～120 ℃ of down dry 6～10h; Dried sample places Muffle furnace to rise to 400～600 ℃ with the programming rate of 120 ℃/h, insulation 2～3h; At last, reduce to room temperature;
In the 5th step, introduce the catalytic active component palladium
With the powder impregnation of good titanium dioxide of load and cerium Zr mixed oxide coating PdCl at 100ppm
21～32h in the solution, then, at 100-120 ℃ of down dry 6～10h; Dried sample places Muffle furnace to rise to 400～600 ℃ with the programming rate of 120 ℃/h, insulation 2～3h; At last, reduce to room temperature, the catalyst that obtains is Pd/CeZrO/TiO
2/ Al
2O
3
Added TiO in the catalyst provided by the present invention
2With the CeZrO mixed oxide be support material, at NO
xCatalytic reduction catalysts in these two kinds of compounds often used, wherein the CeZrO carrier has the effect of tangible storage oxygen.In catalytic reaction process, they and precious metal palladium produce synergy, have not only improved activity of such catalysts but also have improved the stability of catalyst.
The catalyst of a kind of catalytic cleaning of lean-burn engine tail gas proposed by the invention when the content of active component palladium is lower than 0.1wt%, can not well be brought into play the catalytic performance of catalytic active component; When the content of palladium during, not only reduced the catalytic activity of catalyst, and increased the cost of catalyst owing to the increase of palladium content greater than 1.0wt%.The content of catalytic active component Pd is relevant with dip time, along with the increase of dip time, and Pd content height.The content of titanium dioxide surpasses 20wt% in the catalyst, and promptly coating of titanium dioxide is thicker, through roasting, is easy to form and chaps; When content was lower than 14wt%, coating of titanium dioxide was thinner, can not cover aluminium dioxide fully.The too high levels of cerium Zr mixed oxide surpasses at 6.0% o'clock, and the CeZrO that titanium dioxide surface adheres to is too much, has hindered titanium dioxide and has participated in reaction; When cerium Zr mixed oxide content is lower than 3.0%, can not satisfy the needs of experiment.
Content, coating time, number of times and the roasting condition of the ratio of butyl titanate and absolute ethyl alcohol, polyethylene glycol are relevant in the Preparation of catalysts method of a kind of catalytic cleaning of lean-burn engine tail gas proposed by the invention, coating of titanium dioxide and TiO 2 sol proportioning.When the ratio of butyl titanate and absolute ethyl alcohol is low excessively, the colloidal sol of preparation is thickness relatively, influences adhering to of coating; When its ratio was too high, the viscosity of obtained colloidal sol was less, can not satisfy the requirement of coating.The excessive meeting of polyethylene glycol causes adhering to of coating insecure.The thickness of coating time and number of times and coating of titanium dioxide, promptly the content of titanium dioxide has direct relation.The overlong time of coating or the number of times of coating are too much, can cause the too high levels of titanium dioxide, and promptly coating of titanium dioxide is blocked up, through roasting, are easy to form and chap; But the coating time is very short or number of times seldom the time, and the coating of titanium dioxide that alumina surface forms is very thin, can not satisfy actual needs.
Baking temperature and drying time are as the criterion with the coating bone dry.In the dry run,, the temperature of drying need the dry time oversize when being lower than 100 ℃; Baking temperature is high more, drying time the long more drying that helps coating, still, temperature is higher than 120 ℃ and time and surpasses 8h and then consume the too much energy.
The firm degree of sintering temperature and coating and the crystalline structure of coating composition are relevant.When sintering temperature is lower than 400 ℃, can not make coating firm attached to alumina surface; When sintering temperature is higher than 600 ℃,, can cause the transformation of titanium dioxide crystalline form although can improve the adhesive ability of coating.
Catalyst of the present invention has the following advantages:
(1) adopts sol-gel technology preparing TiO
2Coating makes TiO
2Coating evenly distributes on the alumina powder surface, helps the high degree of dispersion of active component, has improved dispersion degree of active components, thereby has improved activity of such catalysts; (2) catalyst of the present invention is introduced the cerium Zr mixed oxide, further improved the decentralization of noble metal catalyst, and had certain storage oxygen function, under excess oxygen, catalyst can be operated in wider temperature range, thereby enlarged the reactivity window; (3) catalyst of the present invention is active component with the precious metal palladium, produces synergy with titanium dioxide and cerium Zr mixed oxide, makes this catalyst to the NO in the exhaust of lean-burn automotive
xHas the good low-temperature catalytic activity; (4) the catalysis of the present invention good characteristic of wide window has at low temperatures solved the cold start-up problem of motor vehicle exhaust emission to a great extent.
Specific embodiment:
Below by specific embodiment, further specify the Catalysts and its preparation method of catalytic cleaning of lean-burn engine tail gas.
Embodiment 1
For the existing narrower problem of catalyst operation window that is used for exhaust of lean-burn automotive,, widen the operation window of catalyst by the content that improves titanium dioxide and cerium Zirconium oxide with the catalyst of following method preparation.
The first step, the preparation of TiO 2 sol
The 28.43ml butyl titanate is dissolved in the 56.87ml absolute ethyl alcohol, the diethanol amine that then adds 4.8ml, after stirring 2h under the room temperature, the water that adds the 9.9ml volume ratio and be 1: 10 is in the mixed solution of ethanol, add the 0.5g molecular weight then and be 2000 polyethylene glycol, ultrasonic again dispersion 10min can obtain yellow transparent colloidal sol;
Second step, the preparation of alumina powder surface titanium dioxide coating
2.0g alumina powder adds 2min in the 50ml titanium colloidal sol, dry 6h under 120 ℃; Repeat this step 2 time repeatedly; Rise to 600 ℃ at Muffle furnace with the programming rate of 120 ℃/h then, insulation 2h.Reduce to room temperature, obtain the alumina powder that area load has coating of titanium dioxide;
The 3rd step, the preparation of cerium zirconium colloidal sol
Cerous nitrate (Ce (NO with 66ml 0.116mol/L
3)
36H
2O) zirconium nitrate (Zr (NO of solution and 80ml 0.0466mol/L
3)
45H
2O) solution mixes, and adding concentration then is the polyethylene glycol 14.5ml of 16.6g/L, and mixed solution is stirred in 80 ℃ of lower magnetic forces, slowly drips 0.1mol/L citric acid 60ml in the process that stirs, and obtains white emulsus CeZrO colloidal sol;
The 4th step, the load of adhering to cerium Zr mixed oxide on the carrier of titanium dioxide
There is the alumina powder of coating of titanium dioxide to immerse in the 50ml cerium zirconium colloidal sol load, takes out behind the 15min, with 120 ℃ of following dry 6h, rise to 600 ℃ at Muffle furnace with the programming rate of 120 ℃/h at last, insulation 2h reduces to room temperature, i.e. Zhi the sample that contains the cerium Zr mixed oxide.The sample that obtains the wherein content of titanium dioxide is 20.0wt%, and the content of cerium Zr mixed oxide is 6.0wt%;
In the 5th step, introduce the catalytic active component palladium
The alumina powder of good titanium dioxide of load and cerium Zr mixed oxide coating is immersed in the PdCl of 50ml 100ppm
21h in the solution, then, dry 6h under 120 ℃; Drying is placed on that the programming rate with 120 ℃/h rises to 600 ℃ in the Muffle furnace, and insulation 2h reduces to room temperature, obtains 0.1%-Pd/CeZrO/TiO
2/ Al
2O
3Catalyst.
Testing result: the content of titanium dioxide is 20wt% in the powder catalyst of preparation, and promptly the thickness of coating of titanium dioxide is higher, helps widening the catalytic reaction temperature range of catalyst.
Embodiment 2
Higher for the existing catalyst reaction temperatures that is used for exhaust of lean-burn automotive, prepare the higher catalyst of catalytic active component palladium content with following method.
The first step, the preparation of TiO 2 sol
The 12.19ml butyl titanate is dissolved in the 73.11ml absolute ethyl alcohol, the diethanol amine that then adds 4.8ml, after stirring 2h under the room temperature, the water that adds the 9.9ml volume ratio and be 1: 10 is in the mixed solution of ethanol, add the 2.0g molecular weight then and be 2000 polyethylene glycol, ultrasonic again dispersion 20min can obtain transparent faint yellow colloidal sol;
Second step, the preparation of alumina powder surface titanium dioxide coating
2.0g alumina powder adds 10min in the 50ml titanium colloidal sol, dry 10h under 100 ℃; Repeat this step 5 time repeatedly; Rise to 400 ℃ at Muffle furnace with the programming rate of 120 ℃/h then, insulation 3h reduces to room temperature, obtains the alumina powder that area load has coating of titanium dioxide;
The 3rd step, the preparation of cerium zirconium colloidal sol
Cerous nitrate (Ce (NO with 66ml 0.116mol/L
3)
36H
2O) zirconium nitrate (Zr (NO of solution and 80ml 0.0466mol/L
3)
45H
2O) solution mixes, and adding concentration then is the polyethylene glycol 32.2ml of 16.6g/L, and mixed solution is stirred in 60 ℃ of lower magnetic forces, slowly drips 0.1mol/L citric acid 60ml in the process that stirs, and obtains white emulsus CeZrO colloidal sol;
The 4th step, the load of adhering to cerium Zr mixed oxide on the carrier of titanium dioxide
There is the alumina powder of coating of titanium dioxide to immerse in the 50ml cerium zirconium colloidal sol load, takes out behind the 5min,, rise to 400 ℃, insulation 3h at Muffle furnace with the programming rate of 120 ℃/h at last with 100 ℃ of dry 10h down.Reduce to room temperature, i.e. Zhi the sample that contains the cerium Zr mixed oxide; The sample that obtains the wherein content of titanium dioxide is 14.0wt%, and the content of cerium Zr mixed oxide is 3.0wt%;
In the 5th step, introduce the catalytic active component palladium
The alumina powder of good titanium dioxide of load and cerium Zr mixed oxide coating is immersed in the PdCl of 50ml 100ppm
232h in the solution, then, dry 10h under 100 ℃; Drying is placed on that the programming rate with 120 ℃/h rises to 400 ℃ in the Muffle furnace, and insulation 3h reduces to room temperature, obtains 1.0%-Pd/CeZrO/TiO
2/ Al
2O
3Catalyst.
Testing result: palladium content is higher in the catalyst of preparation, help reducing the reaction temperature of catalyst, but coating of titanium dioxide is thinner, and part exposes the alumina powder carrier.
Embodiment 3
Higher for the existing catalyst reaction temperatures that is used for exhaust of lean-burn automotive, the problem that operation window is narrower prepares titanium dioxide and cerium Zirconium oxide content is suitable with following method, and the catalyst that palladium content is lower can satisfy breadboard needs.
The first step, the preparation of TiO 2 sol
The 17.02ml butyl titanate is dissolved in the 68.28ml absolute ethyl alcohol, the diethanol amine that then adds 4.8ml, after stirring 2h under the room temperature, the water that adds the 9.9ml volume ratio and be 1: 10 is in the mixed solution of ethanol, add the 1.0g molecular weight then and be 2000 polyethylene glycol, ultrasonic again dispersion 15min can obtain transparent faint yellow colloidal sol;
Second step, the preparation of alumina powder surface titanium dioxide coating
2.0g alumina powder adds 5min in the 50ml titanium colloidal sol, dry 8h under 110 ℃; Repeat this step 2 time repeatedly; Rise to 500 ℃ at Muffle furnace with the programming rate of 120 ℃/h then, insulation 2h reduces to room temperature, obtains the alumina powder that area load has coating of titanium dioxide;
The 3rd step, the preparation of cerium zirconium colloidal sol
Cerous nitrate (Ce (NO with 66ml 0.116mol/L
3)
36H
2O) zirconium nitrate (Zr (NO of solution and 80ml 0.0466mol/L
3)
45H
2O) solution mixes, and adding concentration then is the polyethylene glycol 20ml of 16.6g/L, and mixed solution is stirred in 70 ℃ of lower magnetic forces, slowly drips 0.1mol/L citric acid 60ml in the process that stirs, and obtains white emulsus CeZrO colloidal sol;
The 4th step, the load of adhering to cerium Zr mixed oxide on the carrier of titanium dioxide
There is the alumina powder of coating of titanium dioxide to immerse in the 50ml cerium zirconium colloidal sol load, takes out behind the 10min, with 110 ℃ of following dry 8h; Rise to 500 ℃ at Muffle furnace with the programming rate of 120 ℃/h at last, insulation 2h reduces to room temperature, i.e. Zhi the sample that contains the cerium Zr mixed oxide; The sample that obtains the wherein content of titanium dioxide is 17.02wt%, and the content of cerium Zr mixed oxide is 4.05wt%;
In the 5th step, introduce the catalytic active component palladium
The alumina powder of good titanium dioxide of load and cerium Zr mixed oxide coating is immersed in the PdCl of 50ml 100ppm
23h in the solution, then, dry 8h under 110 ℃; Drying is placed on that the programming rate with 120 ℃/h rises to 500 ℃ in the Muffle furnace, and insulation 2h reduces to room temperature, obtains 0.2%-Pd/CeZrO/TiO
2/ Al
2O
3Catalyst.
Testing result: the catalyst content of titanium dioxide of preparation is 17.02wt%, and promptly coating layer thickness is moderate, and palladium content is lower, and the low-temperature catalytic activity of catalyst is higher, is higher than 70% at 150 ℃ of conversion ratios, operating temperature window broad.
Claims (2)
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| CNB200710010360XA CN100522352C (en) | 2007-02-07 | 2007-02-07 | Catalyst for catalytic cleaning of lean-burn engine tail gas and its preparing process |
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|---|---|---|---|
| CNB200710010360XA CN100522352C (en) | 2007-02-07 | 2007-02-07 | Catalyst for catalytic cleaning of lean-burn engine tail gas and its preparing process |
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|---|---|
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| CN100522352C CN100522352C (en) | 2009-08-05 |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012029050A1 (en) * | 2010-09-02 | 2012-03-08 | Basf Se | Catalyst for gasoline lean burn engines with improved no oxidation activity |
| US9242242B2 (en) | 2010-09-02 | 2016-01-26 | Basf Se | Catalyst for gasoline lean burn engines with improved NO oxidation activity |
| CN106824284A (en) * | 2017-02-13 | 2017-06-13 | 安徽新态环保科技有限公司 | A kind of preparation method of ternary catalyzing unit renovation agent |
| CN109158104A (en) * | 2018-07-28 | 2019-01-08 | 裴泽民 | A kind of preparation method of automobile exhaust detergent |
| CN113398906A (en) * | 2021-06-16 | 2021-09-17 | 北京化工大学 | Zirconium-titanium composite oxide loaded Pd catalyst and preparation method and application thereof |
| CN116139861A (en) * | 2023-01-31 | 2023-05-23 | 安庆市长三角未来产业研究院 | Catalyst suitable for storage and reduction of nitrogen oxides in gas turbines and its preparation and application |
-
2007
- 2007-02-07 CN CNB200710010360XA patent/CN100522352C/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012029050A1 (en) * | 2010-09-02 | 2012-03-08 | Basf Se | Catalyst for gasoline lean burn engines with improved no oxidation activity |
| US9242242B2 (en) | 2010-09-02 | 2016-01-26 | Basf Se | Catalyst for gasoline lean burn engines with improved NO oxidation activity |
| CN106824284A (en) * | 2017-02-13 | 2017-06-13 | 安徽新态环保科技有限公司 | A kind of preparation method of ternary catalyzing unit renovation agent |
| CN109158104A (en) * | 2018-07-28 | 2019-01-08 | 裴泽民 | A kind of preparation method of automobile exhaust detergent |
| CN113398906A (en) * | 2021-06-16 | 2021-09-17 | 北京化工大学 | Zirconium-titanium composite oxide loaded Pd catalyst and preparation method and application thereof |
| CN113398906B (en) * | 2021-06-16 | 2023-08-29 | 北京化工大学 | Zirconium-titanium composite oxide supported Pd catalyst and preparation method and application thereof |
| CN116139861A (en) * | 2023-01-31 | 2023-05-23 | 安庆市长三角未来产业研究院 | Catalyst suitable for storage and reduction of nitrogen oxides in gas turbines and its preparation and application |
| CN116139861B (en) * | 2023-01-31 | 2024-04-16 | 安庆市长三角未来产业研究院 | Catalyst applicable to storage reduction of nitrogen oxides of gas turbine as well as preparation and application thereof |
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| Publication number | Publication date |
|---|---|
| CN100522352C (en) | 2009-08-05 |
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