CN1355066A - Three-effect catalyst for purifying tail gas of car and its preparing process - Google Patents
Three-effect catalyst for purifying tail gas of car and its preparing process Download PDFInfo
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Abstract
A three-effect catalyst for purifying the tail gas of automobile is prepared from the cordierite honeycomb body as matrix through coating internal layer of rare-earth and composite oxides as catalytic component carried by active alumina, coating external layer of noble metal as catalytic component carried by active alumina, hydrogen reduction and activating. Its advantages include low igniting temp., wide three-effect window and long service life.
Description
The present invention relates to automobile exhaust pollution thing (CO, HC, NO
x) complex rare-earth oxidate containing valuable metal-noble metal honeycomb catalyst of purifying of three-effect catalysis and preparation method thereof.
At present, the commercial catalyst that is used for exhausted gases purification on USA and Europe and the Japanese market is noble metal type (as US5157007, UK1499051 etc.), price is expensive, service condition is harsh, easily poisons, and requires very high to the control range of automobile engine air-fuel ratio; In addition, domestic multiple base metal and the rare-earth composite oxide catalyst (as CN85102282A, CN86103200A etc.) once developed of China, it is low to have price, advantages such as anti-poisoning, but because initiation temperature is higher, and the triple effect window is narrower, the life-span is shorter, NO
xReasons such as conversion ratio is lower, market is used and is restricted.
The object of the present invention is to provide the complex rare-earth oxidate containing valuable metal one noble metal honeycomb catalyst that a kind of initiation temperature is low, the triple effect window is wide.
Another object of the present invention is to provide this Preparation of catalysts method.
Three-effect catalyst for purifying tail gas of car of the present invention, with the cordierite honeycomb ceramics as matrix, the inside and outside two coating catalytic active component of coating on it, it is characterized in that undercoating is a catalytic active component with rare earth and the compound transition metal oxide that activated alumina supports, the noble metal that external coating supports with activated alumina is a catalytic active component.
In the present invention, the catalytic active component that the undercoating activated alumina is supported consists of rare earth La, Ce and transition metal Co, the composite oxides of Mn, the mol ratio of each element is La: Ce: Co: Mn=1: 0.2-5.0: 0-1.0: 0-1.0, and the weight ratio of undercoating composite oxides and honeycomb substrate is 1: 5-50.
In the present invention, the external coating catalytic active component consists of precious metals pt, Pd, Rh, wherein Pt: Pd: Rh=1: 0-1: 0-0.3; Or Pd: Pt: Rh=1: 0-1: 0-0.3, the weight ratio of noble metal and honeycomb substrate is 1: 500-1500.
In the catalyst of the present invention, the described activated alumina of inside and outside coating and the weight ratio of cordierite honeycomb substrate are 1: 5-20; Contain La in the wherein said aluminium oxide, Ce, Zr, the oxide of Sr are as stabilizing agent (existing with nitrate in slurries), and the weight ratio of wherein said stabilizing agent and aluminium oxide is 1: 10-40.Adhesive is an aluminium colloidal sol, and wherein the percentage by weight of alundum (Al is 30%-40%.The weight ratio of activated alumina and aluminium colloidal sol is 1: 0.5-2.0.
The matrix of catalyst of the present invention is a CORDIERITE HONEYCOMB CERAMIC CARRIER, and inside has parallel duct, and its hole density is 40-64 hole/square centimeter, and unit weight is 0.45-0.75 gram/cubic centimetre, and water absorption rate is 15%-30%.
Preparation of catalysts method of the present invention comprises following sequential steps:
1) on the cordierite honeycomb carrier, applies the complex rare-earth oxidate containing valuable metal that supports by activated alumina
The undercoating of catalytic active component is wherein in the complex rare-earth oxidate containing valuable metal catalytic active component
In each element mol ratio be La: Ce: Co: Mn=1: 0.2-5.0: 0-1.0: 0-
1.0；
2) apply again by containing that the active oxidation aluminized coating supports applying on the internally coated honeycomb ceramics
The external coating of precious metal catalyst active component;
3) hydrogen reduction activation.
The internally coated painting method of catalyst of the present invention has two kinds.First kind is that branch is coated with method, and active oxidation aluminized coating and complex rare-earth oxidate containing valuable metal catalytic active component are applied on honeycomb substrate successively.Second method is for mixing the method that is coated with, and promptly the active oxidation al composition is with after the complex rare-earth oxidate containing valuable metal catalytic active component is mixed, once property coating on honeycomb substrate.
The painting method of the external coating of catalyst of the present invention has two kinds.First method is for dividing the method that is coated with, and promptly active oxidation aluminized coating and precious metal catalyst active component are applying coating successively on the internally coated honeycomb ceramics; Second method is for mixing the method that is coated with, and promptly the active oxidation al composition is applying once property coating on the internally coated honeycomb ceramics with after the precious metal catalyst active component is mixed.
The first method of the internally coated painting method of catalyst of the present invention-minute be coated with method, the first step is to apply the undercoating activated alumina on cordierite honeycomb bodies, and second step was to apply the complex rare-earth oxidate containing valuable metal catalytic active component on the cordierite honeycomb bodies that applies the undercoating activated alumina.Earlier the cordierite honeycomb carrier is immersed in the undercoating activated alumina slurries of having prepared (or the undercoating activated alumina slurries that will prepare are sprayed on the honeycomb ceramics), then the unnecessary aluminium oxide slurries in the honeycomb channels are blown away with compressed air, at room temperature dried in the shade 2-4 hour, dried 0.5-4 hour in 80 ℃ successively in baking oven or in the drying kiln, dried 2-4 hour for 100-120 ℃, in middle temperature batch-type furnace or middle temperature kiln in 500 ℃-800 ℃ roasting 2-4 hour, promptly finish the coating of undercoating activated alumina on the cordierite honeycomb carrier.Second step was to apply the complex rare-earth oxidate containing valuable metal catalytic active component on the cordierite honeycomb bodies that applies the undercoating activated alumina.Operating procedure and operating condition and the first step are basic identical, and employed coating liquid is the salting liquid that contains the complex rare-earth oxidate containing valuable metal catalytic active component.
The second method of the internally coated painting method of the catalyst of the present invention-mixed method that is coated with, its Step By Condition is similar to the first step of dividing the method that is coated with, and has added the salting liquid of complex rare-earth oxidate containing valuable metal catalytic active component in the undercoating activated alumina slurries of wherein being prepared.
The first method of the painting method of the external coating of catalyst of the present invention-minute be coated with method, its Step By Condition and internally coated painting method-minute be coated with method are similar, have applied undercoating on the wherein coated honeycomb ceramics.In addition, the external coating activated alumina that the first step was used when applying applies slurries can be identical or different with the composition of undercoating alumina coated slurries, and second step when applying use be the coating liquid that contains the precious metal catalyst active component.
The second method of the painting method of the external coating of the catalyst of the present invention-mixed method that is coated with, it is similar that its Step By Condition and the branch of external coating are coated with method, added the salting liquid of the catalytic active component that contains noble metal in the external coating activated alumina slurries that it is characterized in that being prepared.
The hydrogen reduction activation of catalyst of the present invention is in hydrogen reduction furnace, with the ratio feeding nitrogen of nitrogen/hydrogen=4/1 and the gaseous mixture of hydrogen, in 380-480 ℃ of constant temperature 2-4 hour.
The preparation method of activated alumina slurries: at first be preparation aluminium colloidal sol.Take by weighing a certain amount of aluminium flake (purity is greater than 99.5%), dripping hydrochloric acid solution (concentrated hydrochloric acid: water=1: 5-10), under 80-95 ℃ of condition, add hot reflux, treat promptly to make required aluminium colloidal sol after aluminium flake and the hydrochloric acid complete reaction.The active oxidation aluminium powder that will pass through preroast mixes in ball grinder by a certain percentage with aluminium colloidal sol then, and adding certain amount of stabilizer (as La, Ce or Sr, the nitrate of elements such as Ba), on ball mill ball milling 4-24 hour, promptly make required activated alumina slurries.With a water aluminium oxide at 400-500 ℃ of preroast 2-4 hour; Stabilizing agent in the slurries such as La, Ce or Sr, Ba etc. are 3-20% in the percentage by weight of oxide and alundum (Al; The percentage by weight of alundum (Al is 30-40% in the aluminium colloidal sol, and the weight ratio of activated alumina and aluminium colloidal sol is 1: 0.5-2.0.
Prepare the aqueous solution of mixed nitrate according to the above ratio by internally coated main catalytic active component-complex rare-earth oxidate containing valuable metal, and interpolation is total to impregnating agent, and (impregnating agent is oxalic acid or citric acid etc. altogether, the mol ratio of itself and composite oxides is 1: 1-5), promptly make required undercoating catalytic active component coating liquid.Adding the purpose that is total to impregnating agent is to make the catalytic active component mixed liquor more stable, improves catalyst activity, reduces the required sintering temperature of preparation catalyst and also shortens required roasting time.
Preparation has the complex rare-earth oxidate containing valuable metal-precious metal integer honeycomb three-way catalyst of inside and outside two coating structures, must be through drying and the roasting process after repeatedly the cordierite integral honeycomb being applied.All dry runs are after finishing coating, earlier room temperature (20-40 ℃) air dry 2-4 hour, then in dry kiln or baking oven in 80-90 ℃ of oven dry 1-2 hour, then continue 110-120 ℃ of oven dry 2-4 hour.Corresponding roasting process all continues after each dry run.For the internal layer of two coating structures and burning till of outer high-ratio surface activated alumina second carrier, all be in middle temperature kiln or batch-type furnace in 500-800 ℃ of roasting 2-4 hour.For the internal layer of two coating structures and burning till of outer catalytic active component, be in middle temperature kiln or batch-type furnace respectively at 500-800 ℃ and 500-600 ℃ roasting 2-4 hour.Last hydrogen reduction activation process be in hydrogen reduction furnace in 380-500 ℃, press nitrogen and hydrogen with 1: the volume ratio of 0.1-1 feeds the gaseous mixture reductase 12-4 hour of nitrogen and hydrogen.
Description of drawings
Accompanying drawing 1 is the light off characteristics curve after the catalyst 9711# of embodiment 1 wears out.
Accompanying drawing 2 is the air-fuel ratio characteristic curve after the catalyst 9711# of embodiment 1 wears out.
Accompanying drawing 3 is the light off characteristics curve of the catalyst 9809# of embodiment 2.
Accompanying drawing 4 is the air-fuel ratio characteristic curve of the catalyst 9809# of embodiment 2.
The present invention compared with prior art has following features and good effect:
1. on structure forms, adopt hole density be the cordierite honeycomb ceramics of 40-64 hole/square centimeter as catalyst matrix, have larger geometric jacquard patterning unit surface, higher mechanical strength and less gas-flow resistance; Add the stabilizing agents such as adhesive and rare earth in the high-ratio surface activated alumina Second support coating, can make aluminum oxide coating layer firmly and evenly, and high temperature resistant, and the rare earth composition such as cerium oxide has certain oxygen storage capacity, help catalytic effect.
2. catalytic active component adopts inside and outside two coating structure, and internally coated main catalytic active component is the complex rare-earth oxidate containing valuable metal with ABO3 structure, and external coating is take an amount of noble metal as main catalytic active component. The characteristics of this inside and outside two coating structures are, both had the advantage of rare-earth composite oxide catalyst and noble metal catalyst concurrently, when having avoided again rare earth and noble metal to support on same active oxidation aluminized coating, noble metal dispersion is bad, and at high temperature noble metal easily with the shortcoming such as base metal formation alloy. This inside and outside two coated catalysts have lower triple effect initiation temperature, the service life of growing, especially the width of its triple effect " window " is better than existing noble metal or base metal cleaning catalyst for tail gases of automobiles, and its cost is lower than the commodity noble metal catalyst of international market.
3. on preparation technology, in the process of preparation undercoating ABO3 structure complex rare-earth oxidate containing valuable metal, the catalytic active component coating liquid has added common impregnating agent, can make the coating liquid long period keep stable, and can be when the ABO3 structure composite oxide burns till, reduce required sintering temperature, shorten required roasting time; In the process of preparation external coating precious metal catalyst active component, can take first the noble metal composition " to be given and supporting " on the high-ratio surface activated alumina, again will be " have given and having supported " the high-ratio surface active oxidation aluminium powder of noble metal composition and made the coating slurries, be coated on the cordierite integral honeycomb of making the undercoating complex rare-earth oxidate containing valuable metal. The three-way catalyst that adopts this " give and supporting " technique to make can be saved noble metal dosage, reduces cost, improves performance, and is convenient to be connected mutually with " spraying " technique of advanced person.
4. on catalyst performance, the present invention is suitable with international advanced catalysis agent in every respect, and the part importance is better than existing cleaning catalyst for tail gases of automobiles. Be in particular in: the triple effect initiation temperature is low, CO, and HC, the initiation temperature of NOx (referring to that on three-way catalyst these three kinds of pollutants are required minimum temperature during separately by catalyzed conversion 50%) is respectively 200 ℃, and 230 ℃, 215 ℃; Airspeed performance is good, use more than the empty scooter 150000/hr, " filling than " (ratio of the volume of institute's loading catalyst and engine cylinder capacity in the clarifier) is low, only be 0.6-0.9, compare with the clarifier that " filling ratio " is larger, reduce the engine power loss, saved the cost of honeycomb substrate and cage assembly aspect; Triple effect " window " is wide, especially still has higher conversion of nitrogen oxides active in the zone of deflection oxidizing atmosphere; Service life is longer, and through the actual driving examination of ten thousand kilometers of 5-8, catalytic activity is without obvious decline.
Below in conjunction with embodiment, specifically describe this catalyst, the test result of method for preparing catalyst and catalyst performance:
Embodiment 1
Prepare a kind of pair of coating cordierite integral honeycomb three-way catalyst.Its undercoating composition is rare earth-compound transition metal oxide that activated alumina supports, and method for making is activated alumina coating slurries and rare earth and the coating successively respectively of transition metal nitrate coating liquid; The external coating composition is the precious metal catalyst active component that activated alumina supports, and method for making is activated alumina coating slurries and the coating successively respectively of precious metal chloride solution.
The concrete preparation process and the evaluation result of catalyst are as follows:
(1) preparation high-ratio surface second carrier coating material-activated alumina applies slurries earlier.
At first, preparation aluminium colloidal sol.
Take by weighing 65 gram aluminium flakes (purity is greater than 99.5%) and place there-necked flask, drip 10% hydrochloric acid solution (concentrated hydrochloric acid: 500ml water=1: 10), under 80-90 ℃ of condition, add hot reflux, treat promptly to make required aluminium colloidal sol after aluminium flake and the hydrochloric acid complete reaction, be stored in containers for future use after repeating to prepare q.s.
Then, preparation activated alumina coating slurries.
Active oxidation aluminium powder 1000 gram through 400 ℃ of preroasts is added in the ball grinders, and will in 1500ml water, be dissolved with as stabilizing agent 105 the gram lanthanum nitrate hexahydrates, 35 grams, six water cerous nitrates, the mixed solutions and 1000 of 28 gram barium nitrates restrain and also to add in the ball grinder after the aluminium colloidal sols mix and stir, ball milling is 20 hours on ball mill, promptly makes activated alumina coating slurries.
(2) coating undercoating activated alumina coated thing.
To have parallel duct as the inside of matrix (also claiming first carrier), its hole density is 64 hole/square centimeters, unit weight 450 grams per liters, in activated alumina that the cordierite integral honeycomb material soaking of water absorption rate 23% makes the in the above coating slurries 5 minutes, take out the integral honeycomb material then, purge with compressed air and remove unnecessary coating slurries, room temperature (20 ℃) air dry 4 hours, then in baking oven in 80 ℃ of oven dry 2 hours, continue 110 ℃ of oven dry 2 hours.Follow in middle temperature batch-type furnace in 650 ℃ of roastings 2 hours.Promptly make internally coated activated alumina coated thing.
(3) apply rare earth-transition metal composite oxide catalytic active component coated thing that the undercoating activated alumina supports.
Take by weighing 105 gram lanthanum nitrate hexahydrates according to prescription La0.6Ce0.2CoO3,35 grams, six water cerous nitrates, 115 gram cobalt nitrate hexahydrates and altogether impregnating agent citric acid 35 grams be dissolved in the 500ml water, promptly make undercoating catalytic active component coating liquid.The integral honeycomb material soaking that then will apply the undercoating activated alumina in this coating liquid 5 minutes, take out the integral honeycomb material then, remove unnecessary coating liquid with the compressed air purging, room temperature (20 ℃) air dry 4 hours, then in baking oven in 80 ℃ of oven dry 2 hours, continue 110 ℃ of oven dry 2 hours.Then in middle temperature batch-type furnace in 700 ℃ of roastings 2 hours, promptly make internally coated complex rare-earth oxidate containing valuable metal catalytic active component coated thing.
Then, it is outside at the cordierite integral honeycomb material that applies undercoating composite oxides coated thing, apply again by activated alumina and support the external coating coated thing that noble metal constitutes, thereby finish the preparation of two coating integral honeycomb three-way catalysts of present embodiment.
(4) the aluminium oxide coated thing as the catalytic active component carrier of coating external coating.
The integral honeycomb material of undercoating composite oxides coated thing will be applied, be immersed in the external coating activated alumina coating slurries similar and (be with the difference of undercoating aluminium oxide slurries to internally coated composition, the addition of stabilizing agent is 35 gram lanthanum nitrate hexahydrates in the external coating aluminium oxide coating slurries, 105 grams, six water cerous nitrates, 28 gram barium nitrates), take out the integral honeycomb material after 5 minutes, remove unnecessary slurries with the compressed air purging, through and preparation internally coated activated alumina second carrier identical drying and roasting process, promptly make the activated alumina coated thing of external coating.
(5) the precious metal catalyst active component coated thing of coating external coating.
Integral honeycomb material (unit weight 550 grams per liters of external coating activated alumina coated thing will be applied, water absorption rate 28%) is immersed in and is dissolved with chlordene and closes platinum, the tri-chlorination palladium, (its concentration is counted every liter of coating liquid platiniferous 5.5 grams with metal in the coating liquid of precious metal salts such as rhodium chloride, palladium 1.1 grams, rhodium 1.1 grams) 3 minutes, take out the integral honeycomb material then, remove unnecessary coating liquid with the compressed air purging, room temperature (20 ℃) air dry 2 hours, in baking oven,, dried 2 hours for 110 ℃ in 80 ℃ of oven dry 2 hours.Then in middle temperature batch-type furnace in 500 ℃ of roastings 2 hours.
(6) preparation of two coating integral honeycomb three-way catalysts of present embodiment is finished in hydrogen reduction activation.
The integral honeycomb catalyst that applies inside and outside two coating coated things is placed in the hydrogen reduction furnace,, press nitrogen and hydrogen and reduced 3 hours with 1: 0.25 the volume ratio feeding nitrogen and the gaseous mixture of hydrogen at 400 ℃.Complex rare-earth oxidate containing valuable metal-precious metal integer honeycomb the three-way catalyst with inside and outside two coating structures (numbering 9711#) of present embodiment is finished in i.e. preparation.
9711# catalyst performance test result is as follows:
(7) in three-way catalyst laboratory simulation evaluation system, see accompanying drawing 1 through the test result of 900 ℃ of 9711 catalyst light off characteristics after aging.The simulation distribution consist of CO1.70%, O21.80%, C3H61000ppm, C3H81000ppm, NOX1000ppm, CO29.0%.By accompanying drawing 1 as can be known, through 900 ℃ of 9711# catalyst after aging to CO, HC, 50% conversion temperature of NOX is respectively 250 ℃, 270 ℃, 293 ℃.
(8) in three-way catalyst laboratory simulation evaluation system, test result through 900 ℃ of 9711 catalyst air-fuel ratio characteristics after aging is seen accompanying drawing 2, its air-fuel ratio triple effect window (can guarantee CO, HC, the conversion ratio of NOX is all greater than 80% air-fuel ratio scope) be about λ=0.985-1.003, i.e. A/F=14.48-14.74.
(9) two of this kind integral honeycomb catalyst are total to about 1.1 liters of assemblies and are assembled into automobile triple effect catalytic converter (being referred to as KS-3 type purifying vehicle exhaust triple effect catalytic converter), be installed on the Dragon Lord Citroen zx 1.4 i RL EFI cars (having driven a vehicle 47000 kilometers), carry out car load operating condition method (ECE15+EUDC) pollutant emission test.Testing location is Chinese Environmental Science Institute motor vehicle emission test experience chamber.Test result sees Table 1.
Table 1 KS-3 type automobile triple effect catalytic converter car load operating condition method
(ECE15+EUDC) pollutant emission test result
| Project | ??CO(g/km) | ??HC(g/km) | ????NOx(g/km) |
| Test value | ????1.26 | ????0.18 | ??????0.15 |
Data from table 1 as can be known, after KS-3 type purifying vehicle exhaust triple effect catalytic converter is installed, these Citroen zx 1.4 i RL EFI cars are tested through car load operating condition method (ECE15+EUDC) pollutant emission, its pollutant emission value is after multiply by deterioration factor 1.2, be respectively CO=1.51 (g/km), HC+NOx=0.40 (g/km), still be lower than the first kind car conformity of production checkout facility standard value (being equivalent to No. two discharge standards in Europe) that China will come into effect on July 1st, 2005: CO=2.20 (g/km), HC+NOx=0.50 (g/km).
Embodiment 2
Prepare a kind of pair of coating cordierite integral honeycomb three-way catalyst.Its undercoating composition is rare earth-compound transition metal oxide that activated alumina supports, and method for making is activated alumina coating slurries and rare earth and the coating successively respectively of transition metal nitrate coating liquid; The external coating composition is the precious metal catalyst active component that activated alumina supports, and method for making is that activated alumina coating slurries mix the back coating with precious metal chloride solution.
The concrete preparation process and the evaluation result of catalyst are as follows:
(1) applies rare earth-compound transition metal oxide coated thing that the undercoating activated alumina supports
(1) that the prescription of the undercoating coated thing of the three-way catalyst of present embodiment and method for making all are same as embodiment 1 .-(3)..
Then, it is outside at the cordierite integral honeycomb material that applies undercoating composite oxides coated thing, apply again by activated alumina and support the external coating coated thing that noble metal constitutes, thereby finish the preparation of two coating integral honeycomb three-way catalysts of present embodiment.
(2) the precious metal catalyst active component coated thing that supports of activated alumina of coating external coating
At first, prepare the precious metal catalyst active component coating liquid that the external coating activated alumina supports.
In the activated alumina coating slurries identical with embodiment 1 external coating composition, by 4 parts of Pt, 2 parts of Pd, the ratio of 1 part of Rh, add Pt respectively, Pd, the aqueous solution of three kinds of precious metal chlorides of Rh (noble metal total amount be about alundum (Al weight in the activated alumina coating slurries 2%), stirred 30 minutes, and promptly obtained external coating activated alumina-catalytic active component coating liquid.
Then, the integral honeycomb material soaking that will apply undercoating (rare earth-transition metal composite oxide catalytic active component coating) coated thing in external coating (activated alumina supports the precious metal catalyst active component coating) coating liquid about 5 minutes, take out the integral honeycomb material then, remove unnecessary coating liquid with the compressed air purging, room temperature (20 ℃) air dry 2 hours, in baking oven,, dried 2 hours for 110 ℃ in 80 ℃ of oven dry 2 hours.Then in middle temperature batch-type furnace in 500 ℃ of roastings 2 hours.
(3) hydrogen reduction activation.
At last in hydrogen reduction furnace in 400 ℃, press nitrogen and hydrogen feed nitrogen and hydrogen with 1: 0.25 volume ratio gaseous mixture reduction 3 hours.Complex rare-earth oxidate containing valuable metal-precious metal integer honeycomb the three-way catalyst (numbering 9809#) with inside and outside two coating structures is finished in i.e. preparation.
9809# integral honeycomb three-way catalyst is cut into 1.3 centimetres of diameters, and the small cylinder that length is 3.0 centimetres is used for the automobile three-way catalyst benchmark test of laboratory simulation evaluation system.(the simulation distribution consist of CO1.70%, C3H61000ppm, C3H81000ppm, NOX1000ppm, O21.80%, CO29.0%.)
9809# catalyst performance test result is as follows:
(4) test result of 9809# catalyst light off characteristics is seen accompanying drawing 3.By accompanying drawing 3 as can be known, the 9809# catalyst is to CO, HC, and 50% conversion temperature of NOX is respectively 220 ℃, and 222 ℃, 224 ℃,
(5) test result of 9809# catalyst air-fuel ratio characteristic is seen accompanying drawing 4.By accompanying drawing 4 as can be known, the air-fuel ratio triple effect window of 9809# catalyst (can guarantee CO, HC, the conversion ratio of NOX are all greater than 80% air-fuel ratio scope) is about λ=0.987-1.008, i.e. A/F=14.51-14.82
Embodiment 3
Prepare a kind of pair of coating cordierite integral honeycomb three-way catalyst.Its undercoating composition is rare earth-compound transition metal oxide that activated alumina supports, and method for making is that activated alumina coating slurries mix the back coating with rare earth and transition metal nitrate coating liquid; The external coating composition is the precious metal catalyst active component that activated alumina supports, and method for making is that activated alumina coating slurries mix the back coating with precious metal chloride solution.The concrete preparation process of catalyst is as follows:
(1) applies rare earth-compound transition metal oxide coated thing that the undercoating activated alumina supports
Two coating cordierite integral honeycomb three-way catalysts of present embodiment, the prescription and the method for making of the coating liquid of its undercoating (the composite oxide catalytic active component coating that aluminium oxide supports) are: take by weighing 140 gram lanthanum nitrate hexahydrates by prescription La0.8Co0.6 Mn0.4O3,70 gram cobalt nitrate hexahydrates, 56 grams, 50% manganese nitrate solutions reach altogether, and impregnating agent citric acid 35 grams are dissolved in the 500ml water, this mixed solution is added in the activated alumina coating slurries similar to the external coating composition of embodiment 1 (these aluminium oxide slurries should correspondingly add water less), stirred 30 minutes, and promptly made undercoating coating liquid.
Will be identical with embodiment 1 cordierite integral honeycomb material soaking in this coating liquid 5 minutes, take out the integral honeycomb material then, remove unnecessary coating liquid with the compressed air purging, room temperature (20 ℃) air dry 4 hours, then in baking oven in 80 ℃ of oven dry 2 hours, continue 110 ℃ of oven dry 2 hours.Then in middle temperature batch-type furnace in 650 ℃ of roastings 2 hours, promptly make internally coated rare earth-transition metal composite oxide catalytic active component coated thing.
(2) the precious metal catalyst active component coated thing that supports of activated alumina of coating external coating
In the activated alumina coating slurries identical, press 4 parts of Pt with the composition of embodiment 1 external coating, 4 parts of Pd, the ratio of 1 part of Rh, add Pt respectively, Pd, the aqueous chloride solution of three kinds of noble metals of Rh (the noble metal total amount be in the aluminium oxide coating slurries alundum (Al weight 2%), stirred 30 minutes, promptly obtain external coating (the precious metal catalyst active component coating that activated alumina supports) and apply liquid.
The integral honeycomb material soaking that will apply undercoating coated thing (being the complex rare-earth oxidate containing valuable metal catalytic active component coating that activated alumina supports) in external coating (being the precious metal catalyst active component coating that activated alumina supports) coating liquid about 5 minutes, take out the integral honeycomb material then, remove unnecessary coating liquid with the compressed air purging, room temperature (20 ℃) air dry 2 hours, in baking oven,, dried 2 hours for 110 ℃ in 80 ℃ of oven dry 2 hours.Then in middle temperature batch-type furnace in 550 ℃ of roastings 2 hours.
(3) hydrogen reduction activation
At last in hydrogen reduction furnace in 400 ℃, press nitrogen and hydrogen feed nitrogen and hydrogen with 1: 0.25 volume ratio gaseous mixture reduction 3 hours.Complex rare-earth oxidate containing valuable metal-precious metal integer honeycomb the three-way catalyst with inside and outside two coating structures of present embodiment is finished in i.e. preparation.
Claims (10)
1. three-effect catalyst for purifying tail gas of car, with the cordierite honeycomb ceramics as matrix, the inside and outside two coating catalytic active component of coating on it, it is characterized in that undercoating is a catalytic active component with rare earth and the compound transition metal oxide that activated alumina supports, the noble metal that external coating supports with activated alumina is a catalytic active component.
2. according to the described catalyst of claim 1, it is characterized in that the catalytic active component that the undercoating activated alumina is supported consists of rare earth La, Ce and transition metal Co, the composite oxides of Mn, the mol ratio of each element is La: Ce: Co: Mn=1: 0.2-5.0: 0-1.0: 0-1.0, and the weight ratio of undercoating composite oxides and honeycomb substrate is 1: 5-50.
3. according to the described catalyst of claim 1, it is characterized in that the external coating catalytic active component consists of precious metals pt, Pd, Rh, wherein Pt: Pd: Rh=1: 0-1: 0-0.3; Or Pd: Pt: Rh=1: 0-1: 0-0.3, the weight ratio of noble metal and honeycomb substrate is 1: 500-1500.
4. according to the described catalyst of claim 1, it is characterized in that the activated alumina of inside and outside coating and the weight ratio of cordierite honeycomb substrate are 1: 5-20; Contain La in the wherein said aluminium oxide, Ce, Zr, the oxide of Sr are as stabilizing agent, and the weight ratio of wherein said stabilizing agent and aluminium oxide is 1: 10-40.
5. according to the described Preparation of catalysts method of claim 1, comprise following sequential steps:
1) apply the undercoating of the complex rare-earth oxidate containing valuable metal catalytic active component that is supported by activated alumina on the cordierite honeycomb carrier, wherein each element mol ratio is La.Ce: Co: Mn=1: 0.2-5.0: 0-1.0: 0-1.0 in the complex rare-earth oxidate containing valuable metal catalytic active component;
2) apply the external coating that contains the precious metal catalyst active component that supports by the active oxidation aluminized coating on the internally coated honeycomb ceramics again applying;
3) hydrogen reduction activation.
6. according to the described preparation method of claim 5, the wherein said internally coated branch that is applied to is coated with method, and active oxidation aluminized coating and complex rare-earth oxidate containing valuable metal catalytic active component are applied on honeycomb substrate successively.
7. according to the described preparation method of claim 5, the wherein said internally coated method that is coated with of mixing that is applied to, with the active oxidation al composition with after the complex rare-earth oxidate containing valuable metal catalytic active component is mixed, once property coating on honeycomb substrate.
8. according to the described preparation method of claim 5, the branch that is applied to of wherein said external coating is coated with method, and active oxidation aluminized coating and precious metal catalyst active component are being applied coating successively on the internally coated honeycomb ceramics.
9. according to the described preparation method of claim 5, wherein said external coating be applied to the method that is coated with of mixing, the active oxidation al composition with after the precious metal catalyst active component is mixed, is being applied once property coating on the internally coated honeycomb ceramics.
10. according to the described preparation method of claim 5, wherein the hydrogen reduction activation is in hydrogen reduction furnace, with the ratio feeding nitrogen of nitrogen/hydrogen=4/1 and the gaseous mixture of hydrogen, in 380-480 ℃ of constant temperature 2-4 hour.
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| CN 00133312 CN1117623C (en) | 2000-11-23 | 2000-11-23 | Three-effect catalyst for purifying tail gas of car and its preparing process |
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| CN 00133312 CN1117623C (en) | 2000-11-23 | 2000-11-23 | Three-effect catalyst for purifying tail gas of car and its preparing process |
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| CN1117623C CN1117623C (en) | 2003-08-13 |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1311903C (en) * | 2004-12-09 | 2007-04-25 | 天津化工研究设计院 | Method for preparing rare earth base high-performance three-effect catalyst |
| CN100387812C (en) * | 2003-09-30 | 2008-05-14 | 排放技术有限公司 | Coated honeycomb body assembly with measurement sensor |
| CN101161337B (en) * | 2006-10-13 | 2010-09-29 | 比亚迪股份有限公司 | A ternary catalyst and its preparing method |
| CN101242895B (en) * | 2005-06-22 | 2012-01-11 | 巴斯夫欧洲公司 | Catalyst and method for hydrogenating organic compounds containing hydrogenable groups |
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| CN113274879A (en) * | 2021-07-22 | 2021-08-20 | 山东艾泰克环保科技股份有限公司 | Tail gas aftertreatment system for gas engine and preparation method and application thereof |
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- 2000-11-23 CN CN 00133312 patent/CN1117623C/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100387812C (en) * | 2003-09-30 | 2008-05-14 | 排放技术有限公司 | Coated honeycomb body assembly with measurement sensor |
| CN1311903C (en) * | 2004-12-09 | 2007-04-25 | 天津化工研究设计院 | Method for preparing rare earth base high-performance three-effect catalyst |
| CN101242895B (en) * | 2005-06-22 | 2012-01-11 | 巴斯夫欧洲公司 | Catalyst and method for hydrogenating organic compounds containing hydrogenable groups |
| CN101161337B (en) * | 2006-10-13 | 2010-09-29 | 比亚迪股份有限公司 | A ternary catalyst and its preparing method |
| CN102909020A (en) * | 2011-08-01 | 2013-02-06 | 中国石油化工股份有限公司 | Sulfur-resistant catalytic-combustion catalyst and preparation method thereof |
| CN102909020B (en) * | 2011-08-01 | 2014-06-25 | 中国石油化工股份有限公司 | Sulfur-resistant catalytic-combustion catalyst and preparation method thereof |
| CN102626633A (en) * | 2012-03-26 | 2012-08-08 | 清华大学 | Supported composite Co3O4 / CeO2-Al2O3 / cordierite catalyst, preparation method and purpose thereof |
| CN102626633B (en) * | 2012-03-26 | 2014-07-23 | 清华大学 | Supported composite Co3O4 / CeO2-Al2O3 / cordierite catalyst, preparation method and purpose thereof |
| CN109174077A (en) * | 2018-10-17 | 2019-01-11 | 安徽菲扬新材料有限公司 | A kind of vehicle maintenance service catalyst and preparation method thereof |
| CN111672519A (en) * | 2020-03-05 | 2020-09-18 | 王金波 | Noble metal-rare earth perovskite type integral three-way catalyst and preparation method thereof |
| CN113274879A (en) * | 2021-07-22 | 2021-08-20 | 山东艾泰克环保科技股份有限公司 | Tail gas aftertreatment system for gas engine and preparation method and application thereof |
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| CN1117623C (en) | 2003-08-13 |
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