CN1244404C - Catalyst for exhaust purification for internal combustion engnine and preparing method thereof - Google Patents
Catalyst for exhaust purification for internal combustion engnine and preparing method thereof Download PDFInfo
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- CN1244404C CN1244404C CN 02144777 CN02144777A CN1244404C CN 1244404 C CN1244404 C CN 1244404C CN 02144777 CN02144777 CN 02144777 CN 02144777 A CN02144777 A CN 02144777A CN 1244404 C CN1244404 C CN 1244404C
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- main carrier
- carrier layer
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Abstract
The present invention relates to a catalyst for exhaust gas purification of internal combustion engines, which is an internal coating layer taking metal as base material and taking an inorganic oxide film as a carrier. Aluminum oxide is coated on the internal coating layer so as to form a main carrier layer of the catalyst, and noble metals are loaded on the main carrier layer. The present invention is characterized in that ingredients of the internal coating layer contain one or many compounds of ZrO2, CeO2, SiO2, Y2O3 and TiO2. The weight of the components of the internal coating layer in each liter of catalyst is weighed as grams, the main carrier layer takes activated alumina as a main component, rare earth, alkali metals and/or alkaline earth metal oxides are simultaneously added in the main carrier layer, wherein the rare earth accounts for 10 to 20 wt%, the alkali metals and/or alkaline earth metals account for 3 to 8 wt% of and he rest is the activated alumina gamma-Al2O3. Each liter of catalyst comprises 40 to 150 g of main carrier component, the loading noble metals are selected from one or many elements of Pt, Pd and Rh, and each liter of catalyst comprises 0.7 to 1.5 g of noble metal component. The present invention has the advantages of high temperature resistance, corrosion resistance and good purification performance.
Description
Technical field:
The technology of the present invention field belongs to the Purification of IC Exhaustive Gas catalyst, provides between a kind of catalyst coat and metallic carrier adhesion strong especially, and has the catalyst of good purifying property.
Background technology:
The harmful substance that automobile and motorcycle IC engine discharged is carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NO
x), adopt three-way catalyst to reduce the content of these materials usually, to reach discharge standard.But the exhaust composition of two-stroke motorcycle is different with automobile, and the air-fuel ratio A/F of automobile exhaust fluctuates near stoichiometric proportion, and the A/F of two-stroke motorcycle progressively reduces to heavy duty by A/F＞14.63 of idling or A/F＜11.0 when moving fast.If adopt the exhaust catalytic cleaner to add the auxiliary air mode, then the maximum temperature of clarifier can reach 1100 ℃, thereby requires catalyst must have high Lattice Oxygen mobility, big specific area and anti-agglutinatting property energy.Because metallic carrier is different with the thermal coefficient of expansion of catalyst coat, the coating of catalyst comes off easily, causes exhaust to can not get effective purification.In order to address this problem, patent (JP puts down into 3-157143) adopts salic ferrite stainless steel to make carrier, after high-temperature process, form layer oxide film, again active component is coated on this oxide-film, but this kind method is restricted because of material expensive at alloy surface.Patent (EP0813899A2) prepares SiO at metal carrier surface
2Bottom is though can suppress peeling off of coating, (700～800 ℃) limited in one's ability of high temperature resistant impact.The Yamamoto is fortunately given birth to and is waited (TOHKEMY 2001-145836) to use CeO
2Be mixed and made into undercoating with inorganic oxide, employed carrier is identical with patent (EP0813899A2), the i.e. tubulose matrix that has big metering-orifice tooth to process in the corrosion resistant plate upper punch, the coarse easy adhering coating of hole tooth surface, but matrix prepares difficulty limits its practical application greatly, and maximum operation (service) temperature is about 800 ℃.
With the more approaching work of the present invention be that the pure grade of rattan well (CN1174-097A) of Japan supports SiO on metallic carrier
2, CeO
2, Al
2O
3As bottom, dipping Pt, Pd, Rh, but maximum processing temperature is about 800 ℃.Simulation gas and of the present invention suitable is at air speed 17000h
-1During with 400 ℃, the conversion ratio of HC and CO is respectively 65.7% and 90.9%.
The technology contents of invention:
The object of the present invention is to provide a kind of Purification of IC Exhaustive Gas catalyst, it is high temperature resistant, corrosion-resistant, has good purifying property simultaneously.
The invention provides a kind of Purification of IC Exhaustive Gas catalyst, be to be matrix with the metal, with the undercoating of inorganic oxide film as carrier, coating alumina forms the main carrier layer of catalyst on undercoating, on the main carrier layer, support noble metal again and constitute, it is characterized in that:
Internally coated composition is ZrO
2, CeO
2, SiO
2, Y
2O
3, TiO
2In one or more, contain the undercoating composition weight in every liter catalyst and be 10～30 grams;
The main carrier layer is main component with the activated alumina, adds rare earth, alkali metal and/or alkaline earth oxide simultaneously, and its middle rare earth accounts for 10～20% weight, and alkali metal and/or alkaline-earth metal account for 3～8% weight, activated alumina γ-Al
2O
3Surplus; Containing main carrier layer component weight in every liter catalyst is 80～120 grams;
Support noble metal and adopt Pt, Pd and Rh, containing noble metal component weight in every liter catalyst is 0.7～1.5 gram.
Purification of IC Exhaustive Gas of the present invention can also contain transition metal oxide with in the catalyst in the described main carrier layer, and transition metal accounts for 2～10% weight.
Purification of IC Exhaustive Gas of the present invention is with in the catalyst, and metal matrix can be metal plate-like, different shape such as cylindric, cellular.Cellular improve heat-resisting in, have high-specific surface area, and flow resistance is little, has improved detergent power, be particularly suitable for motorcycle and use.Metal matrix of the present invention is preferably selected cylindrical honeycomb Fe-Cr-Al alloy for use, stainless steel tabular or cylindraceous.
Purification of IC Exhaustive Gas of the present invention is with in the catalyst, and the content of noble metal (Pt+Pd)/Rh is preferably 4～8.5: 1 mol ratio, preferred 4～8: 1 mol ratio.Preferably Pt/Pd is 1～6: 1 mol ratio, preferred 3: 1 mol ratios.
The present invention also provides above-mentioned Purification of IC Exhaustive Gas Preparation of catalysts method, it is characterized in that:
One or more soluble-salts among Zr, Ce, Si, Y, the Ti are formed gel mould with sol-gel process on the surface of metal matrix; After air-dry, temperature-programmed calcination, 0.5 ℃/min of programming rate～2 ℃/min, 400～600 ℃ of sintering temperatures 1～4 hour, are prepared into undercoating;
Metal oxide and aluminium oxide slurries are mixed, and mechanical ball milling becomes the particulate latex slurry of particle diameter 0.3～2 μ m; With this slurries dip-coating or spray to and be with on the internally coated matrix, blow down unnecessary slurries then, through 100～120 ℃ of dryings, integral carriers is made in 450～650 ℃ of roastings 2～6 hours;
The noble metal aqueous solution of solubility is mixed with required concentration dip-coating on integral carriers,, is prepared into practical monolithic devices Purification of IC Exhaustive Gas catalyst through 80～110 ℃ of dryings 2～5 hours.
Purification of IC Exhaustive Gas of the present invention is with in the Preparation of catalysts method, and is described by the prepared glue of sol-gel process, if concentration is too high, the gel caking causes Local enrichment, skewness, comes off easily; If concentration is low excessively, need repeatedly coating.Suitable concentration is 0.05～0.8mol/L.
The present invention prepares heat-resisting, corrosion-resistant inorganic oxide film at smooth dull and stereotyped or cellular alloy substrate internal layer, and catalyst coat and alloy carrier adhesion are strengthened.And then on film, apply and have storage oxygen performance, based on activated alumina and be added with oxides such as rare earth, alkali metal and transition metal, make the main carrier coating.Dipping minute amount of noble metal Pt, Pd, Rh on the main carrier coating are prepared into exhaust emission control catalyst again.
The present invention, needs just can obtain needed heat-resisting inorganic oxide coating through further heat treatment with sol-gel process after the gel mould that matrix surface forms is air-dry, and it is too fast to heat up, and glued membrane shrinks, and causes coating bulk cracking, destroys the coating integrality.This coating can form fine and close crystal film in the metal surface, can be observed crystal film under 200 power microscopes is made up of the densest crystal that varies in size, form the loose structure of fine cracks between the point of contact of crystal, this loose structure, can improve and matrix between adhesive force.
The carrier coating made from heat-resisting inorganic oxide and activated alumina among the present invention and the inorganic film of metallic carrier substrate have close physics and chemical property, therefore can strengthen cohesive force therebetween, improved the binding ability between catalyst and metallic carrier, improved also simultaneously that carrier is shock-resistant, the ability of thermal expansion, vibration.In addition, owing to formed the refractory oxides layer, also improved heat-resisting, the corrosion-resistant and ageing resistace of catalyst.
In addition, the preparation of main carrier layer is added with rare earth, alkali metal, alkaline-earth metal and transition metal oxide based on aluminium oxide among the present invention, is prepared into latex slurry through the high energy mechanical ball milling, and this slurries have very high cohesive force.
The catalyst of the present invention preparation has the low characteristics of initiation temperature, particularly through after 1100 ℃, 4 hours burin-in process, when redox ratio is 1, still has very high CO, the oxidability of HC, demonstrates good purifying property and heat resistance.
The specific embodiment:
Embodiment 1:
The used preparation method of this example is identical with aforesaid invention preparation method.1.5: 1: 0.1 in proportion (mol ratios) take by weighing the nitrate of Zr, Ce, Y, make the glue that concentration is 0.5mol/L.The metal beehive carrier of φ 16 * 20mm is immersed in the glue, and it is air-dry to take out the back, and 500 ℃ of roastings 1 hour are measured 10g/L on the oxide of Zr-Ce-Y.Take by weighing 72g γ-Al
2O
3, 14g Ce (NO
3)
36H
2O, 2gLa
2O
3, 8g Zr (NO
3)
45H
2O, 3g MgCO
3, 1g BaO, dilute with water adds an amount of HNO
3Make crosslinking agent, mechanical ball milling is made slurries.The metal beehive carrier that is coated with the Zr-Ce-Y theca interna is immersed in these slurries, take out after-blow and remove unnecessary slurries in the hole, through 4 hours, 500 ℃ roastings of 120 ℃ of dryings 3 hours, be prepared into the main carrier layer, last amount is 85g/L.Again with precious metals pt, Pd, Rh (chlorate), by (Pt+Pd)/Rh=5: 1, Pt/Pd=3: 1, last amount is controlled at 0.8g/L, is impregnated on the main carrier layer, and drying is after 500 ℃ of roastings 3 hours are designated as catalyst A.
Embodiment 2
Metal beehive carrier φ 16 * 20mm, preparation method press (Pt+Pd)/Rh=8: 1 with embodiment 1.Last amount is controlled at 0.8g/L, is dipped on the main carrier layer, and dry after 500 ℃ of roastings 3 hours are designated as catalyst B.
Embodiment 3
Metal beehive carrier φ 16 * 20mm, preparation method be with embodiment 1, by (Pt+Pd)/Rh=4: 1, last amount is controlled at 0.97g/L, is dipped on the main carrier layer, and drying is after 500 ℃ of roastings 3 hours are designated as catalyst C.
Comparative example 1
The preparation method of internal layer is identical with embodiment 1, and activated alumina is as carrier, and treatment conditions are with 1, (Pt+Pd)/and the ratio of Rh is with 1.Last amount is controlled at 1.0g/L, prepares catalyst D.
Comparative example 2
With 68g Zr (NO
3)
45H
2O adds 50mL C
2H
5OH adds an amount of HNO
3Make crosslinking agent, stir and make zirconium colloidal sol.The metal beehive carrier that is coated with the Zr-Ce-Y theca interna is immersed in these slurries, take out after-blow and remove unnecessary slurries in the hole, φ 16 * 20mm metal beehive carrier is immersed in the colloidal sol, it is air-dry to take out the back, through 500 ℃ of roastings 1 hour, according to said method repeat to soak ZrO three times again
2Last amount is 25g/L.With precious metals pt, Pd, Rh (chlorate), press (Pt+Pd)/Rh=5 again: 1, Pt/Pd=3: 1, be impregnated into ZrO
2On the coating, dry after 500 ℃ of roastings 3 hours.Last amount is controlled at 1.12g/L, prepares catalyst E.
Embodiment 4
Catalyst A, B, C, D, E are through 1100 ℃, 4 hours burin-in process, evaluate catalysts durability.
Evaluation method: the exhaust of simulation two-stroke motorcycle is formed as shown in table 1.500 ℃ of reaction temperatures, reaction velocity (GHSV) 52,000h
-1Reaction result is as shown in table 2.
The gas composition of table 1. two-stroke motorcycle exhaust emissions
Feed?gas S(Redox?ratio)
*
1.12 1.01 0.79 0.47 0.29 0.23
CO(％) 1.0 1.0 1.55 1.55 3.2 4.33
C
3H
6(ppm)?1650 1650 4400 4400 6500 8100
O
2(％) 1.5 1.35 2.25 1.35 1.35 1.35
H
2(％) 0.5 0.2 0.2 0.2 0.2 0.2
CO
2(％) 10 10 10 10 10 10
H
2O(％) 10 10 10 10 10 10
N
2 Balance
*The computational methods of redox ratio S are: S=2[O
2]/([CO]+9[C
3H
6])
Reaction result (during S=1) before and after table 2. catalyst ageing
Before and after before and after before and after before and after before and after the conversion ratio catalyst A catalyst B catalyst C catalyst D catalyst E (%)
CO 97.0 97.0 97.0 97.0 97.0?94.09 6.0 85.0 96 75
C
3H
6?89.1 87.9 87.9 85.5 89.7?81.28 6.7 73.9 86 62.4
Embodiment 5
Identical with the condition of test evaluation 1, the initiation temperature of mensuration catalyst A, B, C, D, E, initiation temperature is the temperature that conversion ratio reached 50% o'clock.Result such as table 3.
Initiation temperature before and after table 3. catalyst ageing
Initiation temperature catalyst A catalyst B catalyst C catalyst D catalyst E
Before and after before and after before and after before and after 17 front and back
CO 220 292 205 307 233 320 / 324 174 326
C
3H
6 234 305 221 316 252 343 / 393 228 347
Embodiment 6
Catalyst A, B through big air speed gas shock, after firmly vibrating repeatedly, are weighed, measure the coating stripping ratio, result such as table 4.
Table 4 catalyst coat disbonded test result
Fresh dose of weight of catalyst (g) impacts, vibration back (g) overburden amount (g) is peeled off ratio (%)
A 3.5466 3.5449 0.0017 0.68
B 3.6650 3.6625 0.0025 0.97
Above-mentioned sample result shows that very strong conjugation is arranged between catalyst coat of the present invention and metal matrix, and the catalyst noble metal dosage still has good oxidation susceptibility under than the relatively low condition of other similar techniques.It is characterized in that showing outstanding durability and heat endurance behind low temperature active height, the high temperature ageing.Can obtain practicality motor exhaust catalyst for clarifying with 0.8～1.3g/L noble metal.
Claims (7)
1, a kind of Purification of IC Exhaustive Gas catalyst is to be matrix with the metal, and with the undercoating of inorganic oxide film as carrier, coating alumina forms the main carrier layer of catalyst on undercoating, supports noble metal again and constitute on the main carrier layer, it is characterized in that:
Internally coated composition is ZrO
2, CeO
2, SiO
2, Y
2O
3, TiO
2In one or more, contain the undercoating composition weight in every liter catalyst and be 10～30 grams;
The main carrier layer is main component with the activated alumina, adds rare earth, alkali metal and/or alkaline earth oxide simultaneously, and its middle rare earth accounts for 10～20% weight, and alkali metal and/or alkaline-earth metal account for 3～8% weight, activated alumina γ-Al
2O
3Surplus; Containing main carrier layer component weight in every liter catalyst is 80～120 grams;
Support noble metal and adopt Pt, Pd and Rh, containing noble metal component weight in every liter catalyst is 0.7～1.5 gram, presses (Pt+Pd)/Rh=(4～8.5): 1, and Pt/Pd=1～6: 1.
2, according to the described Purification of IC Exhaustive Gas catalyst of claim 1, it is characterized in that; Contain transition metal oxide in the described main carrier layer, transition metal accounts for 2～10% weight.
3, according to the described Purification of IC Exhaustive Gas catalyst of claim 1, it is characterized in that: described metal matrix is a cylindrical honeycomb Fe-Cr-Al alloy, stainless steel tabular or cylindraceous.
4, according to the described Purification of IC Exhaustive Gas catalyst of claim 1, it is characterized in that: noble metal wherein (Pt+Pd)/Rh is 4～8: 1 mol ratio.
5, according to the described Purification of IC Exhaustive Gas catalyst of claim 4, it is characterized in that: Pt/Pd is 3: 1 mol ratios.
6, the described Purification of IC Exhaustive Gas of a kind of claim 1 Preparation of catalysts method is characterized in that:
One or more soluble-salts among Zr, Ce, Si, Y, the Ti are formed gel mould with sol-gel process on the surface of metal matrix; After air-dry, temperature-programmed calcination, 0.5 ℃/min of programming rate～2 ℃/min, 400～600 ℃ of sintering temperatures 1～4 hour, are prepared into undercoating;
Metal oxide and aluminium oxide slurries are mixed, and mechanical ball milling becomes the particulate latex slurry of particle diameter 0.3～20 μ m; With this slurries dip-coating or spray to and be with on the internally coated matrix, blow down unnecessary slurries then, through 100～120 ℃ of dryings, integral carriers is made in 450～650 ℃ of roastings 2～6 hours;
The noble metal aqueous solution of solubility is mixed with required concentration dip-coating on integral carriers,, is prepared into practical monolithic devices Purification of IC Exhaustive Gas catalyst through 80～110 ℃ of dryings 2～5 hours.
7, according to the described Purification of IC Exhaustive Gas of claim 6 Preparation of catalysts method, it is characterized in that: described is 0.05～0.8mol/L by the prepared gelatin concentration of sol-gel process.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02144777 CN1244404C (en) | 2002-12-13 | 2002-12-13 | Catalyst for exhaust purification for internal combustion engnine and preparing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02144777 CN1244404C (en) | 2002-12-13 | 2002-12-13 | Catalyst for exhaust purification for internal combustion engnine and preparing method thereof |
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| Publication Number | Publication Date |
|---|---|
| CN1507945A CN1507945A (en) | 2004-06-30 |
| CN1244404C true CN1244404C (en) | 2006-03-08 |
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|---|---|---|---|
| CN 02144777 Expired - Fee Related CN1244404C (en) | 2002-12-13 | 2002-12-13 | Catalyst for exhaust purification for internal combustion engnine and preparing method thereof |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5021188B2 (en) * | 2005-08-01 | 2012-09-05 | 株式会社キャタラー | Exhaust gas purification catalyst |
| GB0600130D0 (en) * | 2006-01-06 | 2006-02-15 | Johnson Matthey Plc | Exhaust system comprising zoned oxidation catalyst |
| CN105214680B (en) * | 2015-10-23 | 2017-09-05 | 杭州尹力环保科技有限公司 | A kind of chloride catalyst for purifying organic waste gas and preparation method thereof |
| GB2560944A (en) * | 2017-03-29 | 2018-10-03 | Johnson Matthey Plc | NOx adsorber catalyst |
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2002
- 2002-12-13 CN CN 02144777 patent/CN1244404C/en not_active Expired - Fee Related
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| CN1507945A (en) | 2004-06-30 |
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