CN1132687C - Automobile tail gas cleaning catalyst and its preparation method - Google Patents
Automobile tail gas cleaning catalyst and its preparation method Download PDFInfo
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- CN1132687C CN1132687C CN 99105254 CN99105254A CN1132687C CN 1132687 C CN1132687 C CN 1132687C CN 99105254 CN99105254 CN 99105254 CN 99105254 A CN99105254 A CN 99105254A CN 1132687 C CN1132687 C CN 1132687C
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Abstract
The present invention relates to a catalyst for purifying automobile exhaust. The catalyst for purifying automobile exhaust is prepared from gamma-Al2O3, a porous ceramic carrier prepared from modified rare earth metals and catalytic active components. The catalyst for purifying automobile exhaust is characterized in that the porous ceramic carrier is coated with a coating layer of gamma-Al2O3 and a coating layer of rare earth metal oxide; the catalytic active components comprise transition metal oxide, noble metal and noble metal oxide, wherein the transitional metal mixed oxide is coated on the coating layer of rare earth metal oxide, the noble metals are coated on the coating layer of the transition metal oxide, and the noble metal oxide is coated on the coating layer of the noble metals. The present invention also relates to a preparation method of the catalyst for purifying automobile exhaust.
Description
The present invention relates to a kind of cleaning catalyst for tail gases of automobiles and preparation method thereof.
Along with industrialized process automobile increases exponentially, automobile exhaust gas has become a main source of contaminated environment.In recent years, along with the attention to environmental protection, people recognize that more and more waste gas that automobile discharges is to harmfulness that environment caused.According to estimates in U.S.'s air pollution 60% from various automobiles, 17% from industrial pollution.The waste gas that automobile is discharged mainly is carbon monoxide (CO), unburned hydrocarbon (HC) and nitrogen oxide (NO
x).Nitrogen oxide mainly is NO and NO
2Nitrogen oxide is well-known destruction atmospheric ozone (O
3) material of layer, and ozone layer is the solar ultraviolet filter.The destruction of ozone layer can cause the earth to accept more ultraviolet ray.It is believed that cutaneum carcinoma is relevant with too much reception ultraviolet irradiation.Just because of vehicle exhaust is so serious to the pollution of environment, so countries in the world require more and more higher to the discharge standard of the harmful substance contents in the vehicle exhaust.For example, the every km CO of Europe ECE-8301 standard-required running car discharge capacity must not be higher than 3.16 grams, THC and nitrogen oxide emission must not be higher than 1.13 grams, the every km CO of ECE-8302 standard-required running car discharge capacity must not be higher than 2.5 grams, and THC and nitrogen oxide emission must not be higher than 0.5 gram.The automobile exhaust purifier that catalyst is equipped with in employing is one of the method for automobile exhaust pollution that reduces or eliminates that generally adopts at present, and the key of this method is a catalyst.
For the catalyst that is used for purifying vehicle exhaust, people have carried out a large amount of research and developments, have had a large amount of patent documentations to be seen in report.Generally be to use the carrier of ceramic-like material at existing cleaning catalyst for tail gases of automobiles, use noble metal (as platinum, rhodium, palladium), transition metal and rare earth metal as active component as catalyst.
Chinese patent application 97120101.3 discloses " a kind of ternary composite metal oxide catalyst that is used for automobile exhaust gas purifying and preparation method thereof ", this catalyst comprises honeycomb ceramic carrier, aluminum oxide coating layer and catalytic active component are wherein attached to the γ-Al on the honeycomb ceramic carrier hole wall surface
2O
3Coating contains Y
2O
3And ZrO
2, the catalyst activity structure is divided into inside and outside two layers, all contains precious metal palladium.According to this catalyst, wherein the consumption of noble metal (oxide) is in every kilogram ceramic monolith, between the 8-75 gram.
Chinese patent application 92113299.9 discloses a kind of " noble metal catalyst for purifying waste gas exhausted from IC engine and preparation ", and this catalyst adopts ceramic honey comb and α-Al
2O
3As carrier, adopt Pt, Pd, at least a among Rh and the Ru as the activity of such catalysts component, the consumption of active component is in every liter of ceramic monolith, between the 0.4-2.0 gram.Claim that according to this patent application its catalyst is 90-98% to the clean-up effect of CO, at 85-95%, service life is more than 40,000 kilometers to the clean-up effect of hydrocarbon (CH).But do not demonstrate the test data of the above-mentioned performance of this catalyst in the specification of this application, and the catalyst of this application there is not clean-up effect to nitrogen oxide.
Chinese patent application 96119452.9 discloses a kind of " the atmospheric cleaning catalyst and the method for making of carried noble metal particle ", and this catalyst as carrier, is coated with the Al that contains metal oxide containing precious metals with porous honeycomb ceramic on this carrier
2O
3Coating in every liter of described catalyst, contains the Al of noble metal and metal oxide
2O
3The weight of coating is the 60-180 gram, and the consumption of precious metals pt and Pd is the 0.8-1.4 gram.Do not use rare earth metal and transition metal in this catalyst, because the applicant of this patent application thinks the ABO that contains rare earth metal and transition metal
3Perovskite structure catalyst sulfur resistance and anti-high heat aging performance are poor.Although the content of noble metal is in every liter of catalyst in the catalyst of this application, in the scope of 0.8-1.4 gram, the laboratory tests data of catalyst have only been provided in this application file.And this Preparation of catalysts method more complicated.
Above-mentioned catalyst has all used noble metal as the activity of such catalysts component.Along with the shortage of noble metal resource, recently people study the catalyst of the purifying automobile tail gas that do not use noble metal.
Chinese patent application 85109694.8 discloses honeycomb combustion catalyst of non-precious metal, it comprises uses two carriers and copper, vanadium, manganese, cobalt, the oxide of nickel or the mixed oxide of several compositions in the above-mentioned element, contains the oxide of rare earth element such as lanthanum, cerium, praseodymium, samarium, neodymium, yttrium or its mixture simultaneously as active component.
Chinese patent application 93105063.9 also discloses and Chinese patent application 85109694.8 akin exhausted gases purification catalyst.It comprises the complex carrier of honeybee shape ceramic material and aluminum oxide coating layer, the active component of the mixture of one or more in the oxide of transition metal zirconium, cobalt, nickel, manganese, copper, chromium and the oxide of rare earth element, to activating oxide hydrogen, carbon monoxide, hydrocarbon compound have carried out reduction to be handled.Can think that like this some metallic element activating oxides are converted into metallic element probably.
EP0393517A2 discloses catalytic oxidation and the reduction converter that is used to transform I. C. engine waste gas, and it can be reduced into elemental nitrogen and oxygen with unburned hydrocarbon and carbon monoxide completing combustion and with nitrogen oxide.As catalyst, described converter uses and is selected from Cr, Mn, and Fe, Co, Ni, Cu, Zn, Sn, Ba, the metal oxide of La and Ce, specification have only provided a chemical composition (weight %) and have been: Cu26%, Cr21%; The catalyst of BaO=11%.But when this converter is contained in the mobile muffler exit, must use heater, so that the waste gas that makes this converter that desire is transformed reacts.
But these non-precious metal catalysts are relatively poor at aspects such as low-temperature startup performance, the efficient of removing pernicious gas composition in the tail gas and life of catalyst, can not satisfy the needs as cleaning catalyst for tail gases of automobiles.
An object of the present invention is for the shortcoming that overcomes prior art provides that a kind of bullion content is low, the life-span is long and carbon monoxide, hydrocarbon and nitrogen oxide (NO
x) cleaning catalyst for tail gases of automobiles that transformation efficiency is high.
Second purpose of the present invention provides the method for the above-mentioned catalyst of preparation.
The invention provides a kind of cleaning catalyst for tail gases of automobiles that is used for, comprise with γ-Al
2O
3With rare-earth metal modified porous ceramics carrier and catalytic active component, it is characterized in that described modified ceramic carrier comprises one deck γ-Al that applies on ceramic monolith matrix and the matrix
2O
3Coating and at described γ-Al
2O
3The one deck that applies on the coating is selected from the rare-earth metal oxide coating of lanthanum or cerium or its mixture; Described catalytic active component is the oxide of transition metal and the oxide of noble metal and noble metal, wherein said transition metal is the mixed oxide of cobalt, nickel, manganese, barium and zirconium, described noble metal is platinum or palladium or its mixture, and described metal oxide containing precious metals is the oxide of rhodium; Wherein the mixed oxide of transition metal is coated on the described rare-earth metal oxide coating, and described noble metal is coated on the mixed oxide coatings of described transition metal, and described rhodium oxide is coated on the described noble coatings.
The present invention also provides the method for preparing above-described catalyst, may further comprise the steps: 1) stir down aluminium colloidal sol and deionized water with 1: the weight ratio of 7-10 mixes,
Make the aqueous solution of aluminium colloidal sol; 2) select to select a kind of porous ceramic monolith matrix, step 1) make water-soluble
Soaked 5-15 minute in the liquid, take out after-blow and remove redundant moisture in the ceramic monolith matrix,
Under 120-300 ℃ temperature, make its drying then; 3) with step 2) repeat at least twice, then with the temperature roasting of carrier at 400-700 ℃
Burnt 3-8 hour, and obtained having γ-Al
2O
3The carrier of coating; 4) soluble-salt of lanthanum or cerium or its mixture is dissolved in makes its solubility in the deionized water
The aqueous solution of salt, the carrier that step 3) is obtained soaks in the described aqueous solution then
5-10 minute, 120-180 ℃ make its bone dry after 500-900 ℃ of roasting
Obtained the modified ceramic carrier in 4-8 hour; 5) mixture of the soluble-salt of transition metal is dissolved in makes its solubility in the deionized water
The aqueous solution of salt, the modified ceramic carrier that then step 4) is obtained is described water-soluble
Soaked in the liquid 5-10 minute, 120-180 ℃ make its bone dry after at 400-600
℃ roasting 6-8 hour; 6) soluble-salt of platinum or palladium or its mixture is dissolved in makes its solubility in the deionized water
The aqueous solution of salt, what then step 5) is obtained has a transition metal oxide coating
The modified ceramic carrier soaked 5-10 minute in the described aqueous solution, at 120-180
℃ make behind its bone dry in 400-600 ℃ nitrogen atmosphere reductase 12-4 hour; 7) mixture with the soluble-salt of rhodium is dissolved in the water that makes its soluble-salt in the deionized water
Solution, what then step 6) is obtained has transition metal oxide coating and a noble metal
The modified ceramic carrier of coating soaked 5-10 minute in the described aqueous solution, 120
-180 ℃ make behind its bone dry and to obtain catalysis at 400-600 ℃ of roasting 6-8 hour
Agent.
Brief Description Of Drawings:
Fig. 1 is the clean-up effect curve map after a preferred catalyst of the present invention of measuring on the C08 of the Ford type pulser is aging.
In order to reach purpose of the present invention, the invention provides a kind ofly for the vehicle exhaust cleaning catalyst, comprise with γ-Al2O
3With porous ceramics carrier and the catalytic active component of rare earth metal modification, it is characterized in that described modified ceramic carrier comprises one deck γ-Al that applies on ceramic monolith matrix and the matrix2O
3Coating and at described γ-Al2O
3The one deck that applies on the coating is selected from the rare-earth oxide coating of lanthanum or cerium or its mixture; Described catalytic active component is the oxide of transition metal and the oxide of noble metal and noble metal, wherein said transition metal is the mixed oxide of cobalt, nickel, manganese, barium and zirconium, described noble metal is platinum or palladium or its mixture, and described metal oxide containing precious metals is the oxide of rhodium; Wherein the mixed oxide of transition metal is coated on the described rare-earth oxide coating, and described noble metal is coated on the mixed oxide coatings of described transition metal, and described rhodium oxide is coated on the described noble coatings.
According to catalyst of the present invention, wherein said carrier matrix can be arbitrarily carrier as known in the art, the preferred porous ceramics that adopts, for example hole density be 200-600 hole/square inch, content more than or equal to 92%, water absorption rate is that the cordierite of 20-30% is ceramic.
In the catalyst of the present invention, in every liter of described porous ceramics carrier matrix, γ-Al2O
3The amount of coating is the 4-7 gram, is preferably the 4.5-6 gram; In every liter of described porous ceramics carrier matrix, the amount of described rare-earth oxide coating is the 12.5-30 gram, is preferably the 15-25 gram.
In the catalyst of the present invention, employed rare-earth oxide can be the oxide for independent lanthanum, or the oxide of cerium, or the mixed oxide of lanthanum and cerium. The present inventor finds that by research the use of thulium lanthanum and cerium not only can be played and stablize γ-Al2O
3Crystal structure and the effect that improves its high-temperature stability, can also make catalyst in use can reach rapidly its " flash-point " temperature, that is catalyst is started rapidly under very low temperature. In addition, lanthanum and cerium also have the function that absorbs oxygen and discharge oxygen, are conducive to the reduction of CO and hydrocarbon and the reduction of nitrogen oxide. In these areas, the effect of lanthanum is more obvious. Therefore, in the catalyst of the present invention, as the oxide of thulium, preferably use the oxide of lanthanum, particularly preferably use the mixed oxide of lanthanum and cerium. When using the mixed oxide of lanthanum and cerium, the weight ratio of lanthanum and cerium is 4-1 in the mixture: 1.
In the catalyst of the present invention, in every liter of described porous ceramics carrier matrix, the consumption of described cobalt oxide is the 3-6 gram, is preferably the 4-5 gram, the consumption of manganese oxide is 1-2.5 grams, be preferably the 1-1.7 gram, barytic consumption is the 1.5-2.5 gram, is preferably 1.8-2.3 grams, zirconic consumption is the 1.5-2.5 gram, be preferably the 1.8-2.3 gram, the consumption of nickel oxide is the 0.1-1.0 gram, is preferably the 0.5-0.8 gram.
For the vehicle exhaust cleaning catalyst, generally all contain γ-Al2O
3And thulium, people think that thulium itself also is a kind of catalytic active component. The present inventor finds by years of researches, for containing γ-Al2O
3With the catalyst of thulium, especially when it was used for the vehicle exhaust cleaning catalyst, thulium only was to play to stablize γ-Al2O
3And make it at high temperature still keep the effect of its original crystal structure structure and activity. In addition, in the catalyst of the present invention, the transition metal coating is by thulium coating and γ-Al2O
3Keep apart, therefore, in the preparation process of catalyst, transition metal not can with Al2O
3React, thereby make transition metal give full play to its catalytic activity, thereby greatly reduce the consumption of noble metal. Therefore, according to catalyst of the present invention, in every liter of described porous ceramics carrier matrix, the consumption of described platinum is the 0-0.6 gram, is preferably the 0.2-0.5 gram, the consumption of palladium is the 0-0.6 gram, be preferably the 0.2-0.5 gram, the consumption of rhodium oxide is the 0.04-0.18 gram, is preferably the 0.05-0.15 gram, total noble metal dosage is the 0.3-1.1 gram, is preferably the 0.4-0.8 gram. In above-mentioned three kinds of noble metals, can be the combination of palladium and rhodium, also can platinum and the combination of rhodium, can also be the combination of platinum and palladium and rhodium.
According to catalyst of the present invention, when total noble metal dosage (in every liter of carrier) is in the scope of 0.4-0.8 gram, namely can reach or be higher than at present all automobile exhaust emission standards. Because catalyst of the present invention given full play to each component of catalytic component, the synergy of carrier, transition metal and noble metal for example, therefore, a small amount of increase of noble metal dosage namely can be that catalyst satisfies harsher requirement. For example, when the total noble metal dosage of the consumption in the catalyst (in every liter of carrier) is in the scope of 0.8-1.1 gram, namely can reach or be higher than the requirement of European ECE-8302.
The present invention also provides the preparation method of above-mentioned catalyst, and the method may further comprise the steps: 1) stir lower with aluminium colloidal sol and deionized water with 1: the weight ratio of 7-10 mixes,
Make the aqueous solution of aluminium colloidal sol; 2) select a kind of porous ceramic monolith matrix, in step 1) aqueous solution that makes
Middle immersion 5-15 minute is taken out after-blow except unnecessary water-soluble in the ceramic monolith matrix
Then liquid make its drying under 120-300 ℃ temperature; 3) with step 2) repeat at least twice, then with the temperature of carrier at 400-700 ℃
Roasting 3-8 hour, obtain having γ-Al2O
3The carrier of coating; 4) soluble-salt of lanthanum or cerium or its mixture is dissolved in makes in the deionized water that it is solvable
The aqueous solution of property salt is then with step 3) carrier that obtains is at the described aqueous solution
Middle immersion 5-10 minute, 120-180 ℃ make its bone dry after at 500-900
℃ roasting 4-8 hour obtain the modified ceramic carrier; 5) mixture of the soluble-salt of transition metal is dissolved in the deionized water makes it
The aqueous solution of soluble-salt is then with step 4) the modified ceramic carrier that obtains exists
Soaked 5-10 minute in the described aqueous solution, make it fully dried at 120-180 ℃
Dry rear at 400-600 ℃ of roasting 6-8 hour; 6) soluble-salt of platinum or palladium or its mixture is dissolved in makes in the deionized water that it is solvable
The aqueous solution of property salt is then with step 5) obtain have a transition metal oxide
The modified ceramic carrier of coating soaked 5-10 minute in the described aqueous solution,
120-180 ℃ makes behind its bone dry reductase 12 in 400-600 ℃ hydrogen atmosphere
-4 hours; 7) mixture of the soluble-salt of rhodium is dissolved in makes its soluble-salt in the deionized water
The aqueous solution, then step 6) is obtained have the transition metal oxide coating and
The modified ceramic carrier of noble coatings soaks the 5-10 branch in the described aqueous solution
Clock, 120-180 ℃ make its bone dry after at 400-600 ℃ of roasting 6-8
Hour obtain catalyst.
According to method of the present invention, wherein selected porous ceramics carrier matrix is the cordierite ceramic of 200-600 hole/square inch for hole density.
In the method for the present invention, the soluble-salt of described lanthanum or cerium can be its soluble-salt arbitrarily, but is preferably its nitrate or its acetate.Can use the soluble-salt of lanthanum or cerium respectively, or use the mixture of the soluble-salt of lanthanum and cerium, but preferably use the mixture of the soluble-salt of lanthanum and cerium.When the mixture of the soluble-salt that uses lanthanum and cerium, the weight ratio of lanthanum and cerium is 4-1: 1.
In the method for the present invention, nitrate or acetate that described soluble palladium salt is palladium, solubility platinum salt is the chloroplatinate of platinum, soluble rhodium salt is rhodium chloride.
According to method of the present invention, adopt the method for heating using microwave, high-frequency radio frequency heating or FAR INFRARED HEATING that immersion is had γ-Al
2O
3The ceramic monolith matrix carry out drying at 120-300 ℃.
The present inventor in the preparation process of the modified support in catalyst, will be coated with γ-Al by discovering
2O
3The carrier of coating carries out in the dry process, and the selection of drying mode has very big influence to the performance of the carrier of described modification.Conventional drying mode generally all is the mode that adopts the baking oven heating, and in heating process, because drying is to begin from the surface from outward appearance to inner essence to carry out gradually, the integral structure characteristic of carrier must cause damage in the dry run.According to method of the present invention, will be coated with γ-Al
2O
3When the carrier of coating carries out drying, do not adopt the mode of baking oven heating, but adopt the mode of micro-wave drying, high-frequency radio frequency heat drying or FAR INFRARED HEATING drying that it is carried out drying.Because the present invention has adopted aforesaid drying mode, makes at γ-Al
2O
3In the dry run of coating, the surface area of described coating, pore size etc. can not be affected, and especially can not make the aperture passage of coating that the phenomenon of closed pore can not take place, therefore, the present invention adopts above-described drying mode, and the catalyst carrier that obtains has beyond thought excellent effect.
With non-limiting example the present invention is described in more detail below.
Embodiment 1
In one 5 liters band stirred vessels, add 2100ml deionized water, 300 gram aluminium colloidal sols, stirring obtains the uniform aluminium colloidal sol aqueous solution.(Jingtu Industry Co., Ltd., Shanxi Prov. produces with 500g porous ceramics carrier, hole density is 300-400 hole/square inch, proportion is 650 grams per liters, and water absorption rate is 30% (weight)) in the resulting aluminium colloidal sol aqueous solution, soaked 10 minutes, blow down the aqueous solution unnecessary in the carrier then; With microwave drier 120 ℃ of dryings 2 hours.Dried carrier was soaked in the aforesaid aluminium colloidal sol aqueous solution 10 minutes once more, with microwave drier 120 ℃ of dryings 1 hour.Described immersion-dry run repeats once again.Dried carrier is heated to 650 ℃, is incubated 3 hours, obtain having γ-Al
2O
3The carrier of coating is in every liter of carrier matrix, γ-Al
2O
3The amount of coating is 5 grams.
In one 500 milliliters band stirred vessels, add 150ml deionized water, 21.9 gram lanthanum nitrates, 5.8 gram cerous nitrates, stirring obtains its uniform aqueous solution.With above obtain have γ-Al
2O
3The carrier of coating is soaked in the nitrate aqueous solution of described rare earth metal, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, dried carrier is warming up to 800 ℃, be incubated 5 hours, obtain the catalyst active carrier of modification.
6.0 gram cobalt nitrates, 2.2 gram manganese nitrates, 2.1 gram barium nitrates, 4.8 gram zirconium nitrates and 1.8 gram nickel nitrates are dissolved in 100 ml deionized water, and stirring obtains its uniform mixture solution.The catalyst active carrier of the above-mentioned modification that obtains was soaked in the described aqueous solution 5-10 minute, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, dried carrier is warming up to 500 ℃, be incubated 5 hours.
1.00 gram palladium nitrates fully are dissolved in the uniform aqueous solution that obtains palladium nitrate in 150 ml deionized water.The catalyst active carrier of the above-mentioned modification with transition metal oxide coating that obtains was soaked in the described aqueous solution 5-10 minute, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, dried carrier was reduced 3 hours at 500 ℃ in nitrogen atmosphere.
0.10 gram rhodium chloride fully is dissolved in the uniform aqueous solution that obtains palladium nitrate in 250 ml deionized water.The above-mentioned carrier with transition metal oxide and Metal Palladium coating that obtains was soaked in the described aqueous solution 5-10 minute, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, with dried carrier in air 550 ℃ of roastings 4 hours, obtain catalyst of the present invention.In the catalyst, in every liter carrier matrix, the content of palladium is 0.6 gram, and the content of rhodium is 0.06 gram.
Embodiment 2
In one 5 liters band stirred vessels, add 2850ml deionized water, 300 gram aluminium colloidal sols, stirring obtains the uniform aluminium colloidal sol aqueous solution.(Jingtu Industry Co., Ltd., Shanxi Prov. produces with 500g porous ceramics carrier, hole density is 300-400 hole/square inch, proportion is 650 grams per liters, and water absorption rate is 30% (weight)) in the resulting aluminium colloidal sol aqueous solution, soaked 15 minutes, blow down the aqueous solution unnecessary in the carrier then; With microwave drier 120 ℃ of dryings 1 hour.Dried carrier was soaked in the aforesaid aluminium colloidal sol aqueous solution 10 minutes once more, with microwave drier 150 ℃ of dryings 1 hour.Described immersion-drying repeats secondary again.Dried carrier is heated to 650 ℃, is incubated 4 hours, obtain having γ-Al
2O
3The carrier of coating is in every liter of carrier matrix, γ-Al
2O
3The amount of coating is 5.5 grams.
In one 500 milliliters band stirred vessels, add 150ml deionized water, 23.9 gram lanthanum nitrates, 11.9 gram cerous nitrates, stirring obtains its uniform aqueous solution.With above obtain have γ-Al
2O
3The carrier of coating is soaked in the nitrate aqueous solution of described rare earth metal, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, dried carrier is warming up to 700 ℃, be incubated 5 hours, obtain the catalyst active carrier of modification of the present invention.
7.5 gram cobalt nitrates, 2.8 gram manganese nitrates, 2.3 gram barium nitrates, 4.6 gram zirconium nitrates and 1.6 gram nickel nitrates are dissolved in 100 ml deionized water, and stirring obtains its uniform mixture solution.The catalyst active carrier of the above-mentioned modification that obtains was soaked in the described aqueous solution 5-10 minute, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, dried carrier is warming up to 500 ℃, be incubated 5 hours.
0.70 gram palladium nitrate and 0.29 gram chloroplatinic acid fully are dissolved in the uniform aqueous solution that obtains palladium nitrate in 150 ml deionized water.The catalyst active carrier of the above-mentioned modification with transition metal oxide coating that obtains was soaked in the described aqueous solution 5-10 minute, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, dried carrier was reduced 3 hours at 500 ℃ in nitrogen atmosphere.
0.19 gram rhodium chloride fully is dissolved in the uniform aqueous solution that obtains palladium nitrate in 150 ml deionized water.The above-mentioned carrier with transition metal oxide and Metal Palladium coating that obtains was soaked in the described aqueous solution 5-10 minute, and the described aqueous solution is absorbed equably by described carrier fully.Make its bone dry at 130 ℃ then, with dried carrier in nitrogen atmosphere 550 ℃ of roastings 4 hours, obtain catalyst of the present invention.In the catalyst, in every liter carrier matrix, the content of platinum is 0.18 gram, and the content of palladium is 0.42 gram, and the content of rhodium is 0.12 gram.
Embodiment 3
Repeat the step identical with embodiment 1, just the consumption of lanthanum nitrate is 31.9 grams, the consumption of cerous nitrate is 15.9 grams, and the consumption of cobalt nitrate is 8.0 grams, and the consumption of manganese nitrate is 3.3 grams, the consumption of barium nitrate is 2.6 grams, the consumption of zirconium nitrate is 4.3 grams, and the consumption of nickel nitrate is 1.4 grams, and the consumption of chloroplatinic acid is 0.57 gram, the consumption of radium chloride is 0.09 gram, and the consumption of palladium nitrate is 0.In the catalyst, in every liter carrier matrix, the content of platinum is 0.35 gram, and the content of rhodium is 0.06 gram.
Embodiment 4
Repeat the step identical with embodiment 1, just the consumption of lanthanum nitrate is 37.9 grams, the consumption of cerous nitrate is 13.9 grams, and the consumption of cobalt nitrate is 9.0 grams, and the consumption of manganese nitrate is 3.8 grams, the consumption of barium nitrate is 2.8 grams, the consumption of zirconium nitrate is 4.0 grams, and the consumption of nickel nitrate is 1.2 grams, and the consumption of chloroplatinic acid is 0.81 gram, the consumption of radium chloride is 0.09 gram, and the consumption of palladium nitrate is 0.In the catalyst, in every liter carrier matrix, the content of platinum is 0.50 gram, and the content of rhodium is 0.06 gram.
Embodiment 5
Repeat the step identical with embodiment 2, just the consumption of lanthanum nitrate is 29.9 grams, the consumption of cerous nitrate is 11.9 grams, and the consumption of cobalt nitrate is 9.5 grams, and the consumption of manganese nitrate is 4.2 grams, the consumption of barium nitrate is 3.0 grams, the consumption of zirconium nitrate is 3.8 grams, and the consumption of nickel nitrate is 0.7 gram, and the consumption of chloroplatinic acid is 0.24 gram, the consumption of radium chloride is 0.13 gram, and the consumption of palladium nitrate is 0.42 gram.In the catalyst, in every liter carrier matrix, the content of platinum is 0.15 gram, and the content of palladium is 0.25 gram, and the content of rhodium is 0.08 gram.
Test example 1
The catalyst of the embodiment of the invention 2 is on the C08 of Ford type pulser, carry out waste gas purification test under the following conditions: catalyst at 900 ℃ after aging 12 hours, is set blue mother and reached index (Redox)=1.1, and air speed is 55,000/h, hydrocarbon is the mixture of propylene and propane=2/1, and overall flow rate is 3,300 ml/min, catalyst size is 3/4 inch DX1/2 inch L, programming rate is 10 ℃ of per minutes, and pressure is 5 pounds, and distribution consists of: 1000ppm NO
x, 1500ppm HC, 20ppm SO
2, 1.5%CO, 1.07%O
2, 0.5%H
2, 2.8%H
2O, 12%CO
2, surplus is N
2, the result is:
Initiation temperature: HC-250 ℃, CO-260 ℃
400 ℃ conversion ratio: HC-98%, CO-97%, NOx-84%
500 ℃ conversion ratio: HC-98%, CO-97%, NOx-88%
In addition, see also accompanying drawing 1.
Test example 2
Catalyst of the present invention is according to ECE-8301, GB 11642-89, GB 14761.5-93 and GB/T 3845-93 standard (U.S. EPA-75 standard), adopt the ECE HIGH SPEED TEST system of Beijing Jeep Corporation, the BJ2021E EFI car that with distance travelled is 31,000 kms is tested with car as test.
Experimental condition
1. testing equipment
HORIBA MEXA-9400 emission analyzer and data handling system, precision ± 1%
HORIBA CVS-9300 CFV constant volume samapling system
ONO SOKKI LC-660 photo-electric fifth wheel instrument, precision ± 0.5%
ONO SOKKI DC-DY 55KW direct current power discharging chassis dynamometer, error＜1%
MEXA-441F idle exhaust emission analyzer, precision ± 3%
The automobile-used revolution counter of ONO SOKKI CT-650B, precision ± 1%
Japan ONO SKKI chassis dynamometer, precision ± 2%
2, test loads by following road load:
| The speed of a motor vehicle (km/h) | 10 | 20 | 30 | 40 | 50 | 60 |
| Road load (kw) | 0.51 | 1.20 | 2.12 | 3.18 | 4.76 | 6.70 |
| The speed of a motor vehicle (km/h) | 70 | 80 | 90 | 100 | 110 | 120 |
| Road load (kw) | 8.98 | 11.85 | 15.65 | 21.14 | 26.78 | 32.95 |
3, result of the test
(1) idle exhaust emission
| Catalyst | The control form | High idle speed | Idling | ||
| CO(％) | HC(ppm) | CO(％) | HC(ppm) | ||
| Comparative Examples * | Closed loop | 0.01 | 6 | 0.02 | 9 |
| Embodiment 1 | Closed loop | 0.01 | 10 | 0.04 | 12 |
| Embodiment 2 | Closed loop | 0.01 | 7 | 0.03 | 13 |
| Embodiment 3 | Closed loop | 0.01 | 9 | 0.04 | 12 |
| Embodiment 3 | Closed loop | 0.01 | 10 | 0.05 | 14 |
| Embodiment 3 | Closed loop | 0.01 | 8 | 0.03 | 10 |
| Embodiment 4 | Closed loop | 0.01 | 7 | 0.04 | 12 |
| Embodiment 5 | Closed loop | 0.01 | 9 | 0.03 | 13 |
* U.S. CHRYSLER cleaning catalyst, wherein, in every liter of catalyst, total bullion content is 1.4 grams.
(2) according to ECE-8301 operating mode emission result
| Catalyst | Control mode | HC+NOx(g/Km) | CO(g/Km) | Remarks |
| Comparative Examples * | Closed loop | 0.27 | 1.59 | U.S. ECU |
| Embodiment 1 | Closed loop | 0.50 | 0.93 | U.S. ECU |
| Embodiment 2 | Closed loop | 0.25 | 1.25 | U.S. ECU |
| Embodiment 3 | Closed loop | 0.44 | 1.53 | U.S. ECU |
| Embodiment 3 | Closed loop | 0.51 | 1.06 | Homemade 3#ECU |
| Embodiment 3 | Closed loop | 0.58 | 0.99 | Homemade 3#ECU |
| Embodiment 4 | Closed loop | 0.53 | 1.55 | Homemade 3#ECU |
| Embodiment 5 | Closed loop | 0.48 | 1.94 | Homemade 3#ECU |
| Limit value | 1.13 | 3.16 | ECE-8301 |
* U.S. CHRYSLER cleaning catalyst, wherein, in every liter of catalyst, total bullion content is 1.4 grams, during test, catalyst consumption is 3.2 liters.And the consumption of catalyst of the present invention when test is 2.4 liters.
The result shows that catalyst of the present invention reaches and surpass the waste gas emission standard of ECE-8301 regulation.In addition, also use catalyst of the present invention to carry out road performance test, when travelling 3.5 ten thousand kms, the purification efficiency of CO, HC is all more than 98%, NO
xPurification efficiency is more than 90%, and when travelling 80,000 kms, the purification efficiency of CO, HC is all more than 90%, NO
xPurification efficiency more than 85%.Show that catalyst of the present invention has good waste gas purification effect and long service life.
Claims (14)
1, a kind of catalyst that is used for purifying vehicle exhaust comprises with γ-Al
2O
3With rare-earth metal modified porous ceramics carrier and catalytic active component, it is characterized in that described modified ceramic carrier comprises one deck γ-Al that applies on ceramic monolith matrix and the matrix
2O
3Coating and at described γ-Al
2O
3The one deck that applies on the coating is selected from the rare-earth metal oxide coating of lanthanum or cerium or its mixture, in every liter of described porous ceramics carrier matrix, described γ-Al
2O
3The amount of coating is the 3.5-7 gram, and the amount of described rare-earth metal oxide coating is the 12.5-30 gram; Described catalytic active component is the oxide of transition metal and the oxide of noble metal and noble metal, wherein said transition metal is the mixed oxide of cobalt, nickel, manganese, barium and zirconium, described noble metal is platinum or palladium or its mixture, and described metal oxide containing precious metals is the oxide of rhodium; Wherein the mixed oxide of transition metal is coated on the described rare-earth metal oxide coating, and described noble metal is coated on the mixed oxide coatings of described transition metal, and described rhodium oxide is coated on the described noble coatings.
2, catalyst as claimed in claim 1 is characterized in that described porous ceramics carrier matrix is for having the cordierite ceramic in 200-600 hole per square inch.
3, catalyst as claimed in claim 1 or 2 is characterized in that in every liter of described porous ceramics carrier matrix, described γ-Al
2O
3The amount of coating is the 4.5-6 gram, and the amount of described rare-earth metal oxide coating is the 15-25 gram.
4, catalyst as claimed in claim 1 is characterized in that described rare-earth oxide is the mixed oxide of lanthanum and cerium, and wherein the weight ratio of lanthanum and cerium is 4-1: 1.
5, catalyst as claimed in claim 1, it is characterized in that in every liter of described porous ceramics carrier matrix, the consumption of described cobalt oxide is the 3-6 gram, the consumption of manganese oxide is the 1-2.5 gram, barytic consumption is the 1.5-2.5 gram, zirconic consumption is the 1.5-2.5 gram, and the consumption of nickel oxide is the 0.1-1.0 gram.
6, catalyst as claimed in claim 5, it is characterized in that in every liter of described porous ceramics carrier matrix, the consumption of described cobalt oxide is the 4-5 gram, the consumption of manganese oxide is the 1.5-2 gram, barytic consumption is the 1.8-2.3 gram, zirconic consumption is the 1.8-2.3 gram, and the consumption of nickel oxide is the 0.5-0.8 gram.
7, catalyst as claimed in claim 1, it is characterized in that in every liter of described porous ceramics carrier matrix the consumption of described platinum is the 0-0.6 gram, the consumption of palladium is the 0-0.6 gram, the consumption of rhodium oxide is the 0.04-0.18 gram, and total noble metal dosage is the 0.3-1.1 gram.
8, catalyst as claimed in claim 7 is characterized in that in every liter of described porous ceramics carrier matrix, and described total noble metal dosage is the 0.4-0.8 gram.
9, prepare the method for the described catalyst of claim 1, may further comprise the steps:
1) stir down aluminium colloidal sol and deionized water with 1: the weight ratio of 7-10 is mixed
Evenly, make the aqueous solution of aluminium colloidal sol;
2) select a kind of porous ceramic monolith matrix, make in step 1)
The aqueous solution in soaked 5-15 minute, take out after-blow and remove the ceramic monolith matrix
Middle redundant moisture makes its drying then under 120-300 ℃ temperature;
3) with step 2) repeat at least twice, then with carrier at 400-700 ℃
Temperature roasting 3-8 hour obtains having γ-Al
2O
3The carrier of coating;
4) soluble-salt of lanthanum or cerium or its mixture is dissolved in the deionized water makes it
The aqueous solution of soluble-salt, the carrier that step 3) is obtained is described then
The aqueous solution in soaked 5-10 minute, make it dried fully at 120-180 ℃
Dry back obtained the modified ceramic carrier at 500-900 ℃ of roasting 4-8 hour;
5) mixture of the soluble-salt of transition metal is dissolved in the deionized water makes it
The aqueous solution of soluble-salt, the modified ceramic that step 4) is obtained is carried then
Body soaked 5-10 minute in the described aqueous solution, made at 120-180 ℃
Behind its bone dry at 400-600 ℃ of roasting 6-8 hour;
6) soluble-salt of platinum or palladium or its mixture is dissolved in the deionized water makes it
The aqueous solution of soluble-salt, what then step 5) is obtained has a transition gold
The modified ceramic carrier that belongs to oxide coating soaks 5 in the described aqueous solution
-10 minutes, 120-180 ℃ make its bone dry after at 400-600
℃ nitrogen atmosphere in reductase 12-4 hour;
7) mixture of the soluble-salt of rhodium is dissolved in makes its solubility in the deionized water
The aqueous solution of salt, what then step 6) is obtained has a transiting metal oxidation
The modified ceramic carrier of thing coating and noble coatings is in the described aqueous solution
Soaked 5-10 minute, 120-180 ℃ make its bone dry after 400
-600 ℃ obtained catalyst in roasting 6-8 hour.
10, method as claimed in claim 9 is characterized in that described porous ceramics carrier matrix is for having the cordierite ceramic in 200-600 hole per square inch.
11, method as claimed in claim 9 is characterized in that step 4) and 5) described soluble-salt is nitrate or acetate.
12, method as claimed in claim 9 is characterized in that the described soluble-salt of step 6) is the nitrate or the acetate of palladium, the chloroplatinate of platinum, and the described salt of step 7) is rhodium chloride.
13, method as claimed in claim 9 is characterized in that the described soluble-salt of step 4) is the mixture salt of lanthanum and cerium, and wherein the weight ratio of lanthanum and cerium is 4-1: 1.
14, method as claimed in claim 9 is characterized in that immersion is had γ-Al
2O
3The ceramic monolith matrix carry out drying with the method for heating of heating using microwave, high-frequency radio frequency or FAR INFRARED HEATING.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99105254 CN1132687C (en) | 1999-04-30 | 1999-04-30 | Automobile tail gas cleaning catalyst and its preparation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99105254 CN1132687C (en) | 1999-04-30 | 1999-04-30 | Automobile tail gas cleaning catalyst and its preparation method |
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|---|---|
| CN1272401A CN1272401A (en) | 2000-11-08 |
| CN1132687C true CN1132687C (en) | 2003-12-31 |
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|---|---|---|---|
| CN 99105254 Expired - Fee Related CN1132687C (en) | 1999-04-30 | 1999-04-30 | Automobile tail gas cleaning catalyst and its preparation method |
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20060100447A (en) * | 2003-11-24 | 2006-09-20 | 다우 글로벌 테크놀로지스 인크. | Catalyst for a diesel particulate filter |
| CN100335168C (en) * | 2005-07-14 | 2007-09-05 | 浙江大学 | Preparation method of cerium lanthanium complex oxide |
| CN100386150C (en) * | 2005-08-17 | 2008-05-07 | 云南菲尔特环保科技有限公司 | Carrier of ceramics catalyst, and microparticles collection device of constituting the carrier and their preparation method |
| CN103551165A (en) * | 2013-11-04 | 2014-02-05 | 中国科学院福建物质结构研究所 | Transitional-element-doped nitrogen oxide purification catalyst as well as preparation method and application thereof |
| CN103846109B (en) * | 2014-03-18 | 2015-12-02 | 哈尔滨工业大学 | Foam metal aluminium surface modification for catalysis agent carrier and preparation method thereof and utilize this carrier to prepare the method for alcohol reforming catalyst |
| CN103949244B (en) * | 2014-05-19 | 2015-12-02 | 哈尔滨工业大学 | Be the preparation method of the platinum catalyst of carrier with Porous foam aluminimun for methanol reformer combustion chamber |
| CN105195174B (en) * | 2015-10-20 | 2017-03-22 | 浙江通源环保科技有限公司 | Catalyst used for automobile exhaust particle catalytic filter and preparation method for catalyst |
| CN105200422B (en) * | 2015-10-20 | 2018-01-30 | 嵊州市万智网络科技有限公司 | A kind of vehicle exhaust particulate filter coating material and preparation method thereof |
| CN105148675B (en) * | 2015-10-20 | 2017-07-21 | 成都东洋蓝环保设备有限公司 | A kind of vehicle exhaust filter method |
| CN106000420B (en) * | 2016-06-03 | 2019-04-26 | 华烁科技股份有限公司 | One removing N2O and NOxCatalyst and preparation method thereof |
| CN108607552A (en) * | 2018-05-07 | 2018-10-02 | 华北电力大学（保定） | A kind of high-efficient purification auto-exhaust catalyst |
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1999
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| CN1272401A (en) | 2000-11-08 |
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