Cerium-based composite oxides supported precious metal three-effect catalyst and preparation method thereof

A composite oxide, three-way catalyst technology, applied in metal/metal oxide/metal hydroxide catalysts, physical/chemical process catalysts, chemical instruments and methods, etc. Conversion performance, simple preparation process and good repeatability

Inactive Publication Date: 2009-05-20
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

According to the research, the three-way catalyst with the same composition and the same noble metal loading, due to the noble metal in CeO 2 -ZrO 2 and Al 2 o 3 There are great differences in the states of the two different catalytic coatings, which directly affect the catalytic effect of the catalyst on the three types of pollutants.

Method used

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  • Cerium-based composite oxides supported precious metal three-effect catalyst and preparation method thereof
  • Cerium-based composite oxides supported precious metal three-effect catalyst and preparation method thereof
  • Cerium-based composite oxides supported precious metal three-effect catalyst and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The ratio of CO:NO in the exhaust gas is 2.2%: 500ppm=44:1, and the air-fuel ratio λ=1.000.

[0024] Take 3.86g of cerous nitrate and 1.24g of zirconium nitrate and dissolve in 12.7mL of deionized water, wherein the molar concentration ratio Ce:Zr=1:0.5, configure the first mixed aqueous solution with an ion concentration of 1mol / L, and mix well. Prepare 4mol / L ammonia solution, add the prepared first mixed aqueous solution to 7.65mL ammonia solution at a rate of 2mL / min, adjust pH=9, add polyethylene glycol 0.1g, fully stir, let stand, 70 Aging at ℃ for 12h, drying at 100℃ for 12h after vacuum filtration, and calcining at 500℃ for 5h.

[0025] Dissolve 14.72g of aluminum nitrate in 39.23mL of deionized water, prepare a second aqueous solution with an ion concentration of 1mol / L, add the second aqueous solution dropwise to 21.40mL of 4mol / L ammonia solution, adjust the pH to 10, and add polyethylene glycol 0.1g, aging, drying, roasting, the method is the same as before...

Embodiment 2

[0029] The ratio of CO:NO in the exhaust gas is 0.8%: 1400ppm=5.7, and the air-fuel ratio λ=1.003.

[0030] Take 20.22g of cerium sulfate, 16.96g of zirconium nitrate, and 0.50g of strontium nitrate and dissolve them in 200g of deionized water, wherein the molar concentration ratio Ce:Zr=1:1, the mass fraction of Sr is 3wt.%, and the total ion concentration is 0.5mol / The first aqueous solution of L. Configure 3.5mol / L ammonia solution, add the prepared first mixed aqueous solution to 7.65mL ammonia solution at a rate of 2mL / min, adjust pH=9, add polyethylene glycol 0.1g, stir fully, let stand, Aging at 70°C for 12h, vacuum filtration, drying at 100°C for 12h, and calcination at 500°C for 5h.

[0031] Dissolve 12.66g of aluminum chloride in 63.5g of deionized water, configure a second aqueous solution with an ion concentration of 1.5mol / L, add it to 71.25mL of 3.5mol / L ammonia solution at a rate of 2mL / min, and adjust the pH to 10. Subsequent processing is the same as before...

Embodiment 3

[0035] The ratio of CO:NO in the exhaust gas is 1.6%: 950ppm=16.8, and the air-fuel ratio λ=1.000.

[0036] Dissolve 87.64g of cerium ammonium nitrate, 117.92g of zirconium nitrate and 3.80g of copper nitrate in 100g of water, wherein the molar concentration ratio Ce:Zr=1:2, Cu mass fraction is 5% and dissolve in 350g of deionized water to configure the total ion concentration It is the first aqueous solution of 1.5 mol / L. Configure 4.5mol / L ammonia solution, add the prepared first mixed solution to 37.2mL ammonia solution at a rate of 2mL / min, adjust pH=8.5, add polyethylene glycol 0.25g, fully stir, let stand, Aging at 70°C for 12h, vacuum filtration, drying at 100°C for 12h, and calcination at 500°C for 5h.

[0037] Dissolve 53.25g of aluminum chloride in 500g of deionized water, configure a second aqueous solution with an ion concentration of 0.5mol / L, add it to 166.7mL of 4.5mol / L ammonia solution at a rate of 2mL / min, adjust the pH to 10, and then Same as before.

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Abstract

The invention relates to a cerium-based composite oxide loaded noble metal three-way catalyst and a preparation method thereof. The method comprises the steps that soluble cerium, zirconium salt, aluminum salt and soluble modified elements as raw materials are used to prepare a carrier material gamma-Al2O3 and Ce1-xZrxMyO2 by a coprecipitation method, wherein x is between 0.25 and 0.75 by molar fraction; M can be lanthanum, praseodymium, strontium or copper; y is between 0 and 0.1 by weight percentage; the mass ratio of alumina to ceria-zirconia is between 0.5 and 2; and 0.25 to 3.0 percent of noble metal of the catalyst is loaded on the carrier by an equal volume method to prepare the high-performance cerium-based composite oxide loaded noble metal three-way catalyst. The three-way catalyst which is controllably prepared by the method can furthest improve the transformation performance of the catalyst, and can effectively remove carbon monoxide (CO), nitrogen oxide (NOx) and hydrocarbon (HC). The preparation method has the advantages of simple process and good repetitiveness, and is favorable for industrial production.

Description

technical field [0001] The invention belongs to the field of catalytic purification of automobile exhaust, and in particular relates to a cerium-based composite oxide-supported noble metal three-way catalyst and a preparation method thereof, specifically a catalyst for exhaust gases with different components, namely carbon monoxide, nitrogen oxides and hydrocarbons With different contents, coprecipitation method and equal-volume impregnation method can be used to control the preparation of high-performance three-way catalysts loaded with cerium-based composite oxides and noble metals. Background technique [0002] The most effective and widely used vehicle exhaust treatment measures are the installation of off-board exhaust purifiers, which can significantly reduce pollutants such as carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC) in vehicle exhaust. The three-way catalyst has become the key technology of the off-machine purifier because it can efficiently ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/63B01J23/89B01D53/94
CPCY02T10/22Y02A50/20Y02T10/12
Inventor 沈美庆翁端温静王军
Owner TIANJIN UNIV
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