Single-coating three-way catalyst and preparation method thereof

A three-way catalyst, single-coating technology, applied in chemical instruments and methods, physical/chemical process catalysts, separation methods, etc. High temperature aging ability, low cost, prolong life effect

Active Publication Date: 2015-07-22
WUXI WEIFU ENVIRONMENT PROTECTION CATALYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to solve the disadvantages that the existing three-way catalyst has poor reducibility, and the precious metal palladium-rhodium will generate a palladium-rho

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] A kind of double-coated three-way catalyst for automobile exhaust gas. The honeycomb cordierite with a specification of Ф118.4mm×152.4mm, a pore density of 600cpsi, a pore wall thickness of 4mil, and a volume of 1.678L is used as the carrier; the carrier is first coated with a Pd layer, coated with Coating amount is 125g / L, Pd content is 27g / ft 3 ; Then apply a layer of Rh layer on the Pd layer, the coating amount is 75g / L, and the Rh content is 3g / ft 3 .

[0022] Mix the second cerium-zirconium composite oxide of 2000g, activated alumina and an appropriate amount of deionized water, the mass ratio of the second cerium-zirconium composite oxide and activated alumina is 1:1, add Pd solution ball mill after fully stirring, and obtain The slurry is coated on the above-mentioned honeycomb carrier, dried at 150° C. for 10 minutes, and then baked at 500° C. for 90 minutes to obtain the Pd coating.

[0023] Mix 1000g of the first cerium-zirconium composite oxide, 95g of acti...

Embodiment 2

[0026] A single-coated three-way catalyst for automobile exhaust, using honeycomb cordierite with a specification of Ф118.4mm×152.4mm, a pore density of 600cpsi, a pore wall thickness of 4mil, and a volume of 1.678L as the carrier; a layer containing Pd, Rh coating, coating amount is 200g / L, Pd content is 27g / ft 3 ;Rh content is 3g / ft 3 .

[0027]The first cerium-zirconium composite oxide of 3000g, the second cerium-zirconium composite oxide and activated alumina are mixed with an appropriate amount of deionized water in a mass ratio of 1:2:2.5, and after fully stirring, Pd and Rh mixed solution are added to ball mill, and the The obtained slurry is coated on the above-mentioned honeycomb carrier, dried at 150°C for 10 minutes, and then the dried honeycomb carrier with Pd / Rh coating is fired at 500°C for 90 minutes to obtain a Pd / Rh single-layer three-layer metacatalyst.

[0028] The main composition of the above-mentioned first cerium-zirconium composite oxide is: 80wt% Zr...

Embodiment 3

[0030] A single-coated three-way catalyst for automobile exhaust, using honeycomb cordierite with a specification of Ф118.4mm×152.4mm, a pore density of 600cpsi, a pore wall thickness of 4mil, and a volume of 1.678L as the carrier; a layer containing Pd, Rh coating, coating amount is 200g / L, Pd content is 27g / ft 3 ;Rh content is 3g / ft 3 .

[0031] Precious metal Pd is heat-fixed on the second cerium-zirconium composite oxide of 1090.91g and 1363.64g activated alumina, mixes with proper amount of deionized water again, after fully stirring, with Ca(OH) 2 、Ba(OH) 2 , Sr(OH) 2 , NH 3 ·H 2 One or several kinds of O etc. adjust the pH of the slurry between 4.0 and 8.5, ball mill the slurry, add 545.45g of the first cerium-zirconium composite oxide that has been heat-fixed Rh, and use Ca(OH) 2 、Ba(OH) 2 , Sr(OH) 2 , NH 3 ·H 2 O, HNO 3 , HAc and other solutions to adjust the pH of the slurry between 4.0 and 8.5, add the obtained slurry to the above-mentioned honeycomb carr...

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PUM

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Abstract

The invention relates a single-coating three-way catalyst and a preparation method thereof. The catalyst takes honeycomb cordierite as a carrier, a framework in the carrier is coated with a single coating loaded with Pd and Rh respectively, the single coating comprises first ceria-zirconia composite oxide, second ceria-zirconia composite oxide and activated aluminum oxide, Pd is loaded on the second ceria-zirconia composite oxide and the activated aluminum oxide, Rh is loaded on the first ceria-zirconia composite oxide, and the mass ratio of the first ceria-zirconia composite oxide, the second ceria-zirconia composite oxide and the activated aluminum oxide is (0.5-1): (0.5-4) : (1-5). The preparation method is simple, Pd and Rh are loaded on the first ceria-zirconia composite oxide and the second ceria-zirconia composite oxide with a thermosetting method respectively, Pd-Rh alloy generation is avoided, high activity and high temperature aging resistance of the catalyst are guaranteed, the service life of the catalyst is prolonged, and the capability for purifying carbon monoxide, nitrogen oxide and hydrocarbon is better.

Description

technical field [0001] The invention relates to a single-coated three-way catalyst and a preparation method thereof, belonging to the technical field of catalyst preparation for automobile tail gas purification. Background technique [0002] The pollutants in automobile exhaust are mainly composed of carbon monoxide (CO), nitrogen oxides (NOx) and hydrocarbons (HC), which pose a great threat to the environment and human health. Installing a three-way catalyst can effectively convert harmful components of carbon monoxide (CO), nitrogen oxides (NOx), and hydrocarbons (HC) into carbon dioxide (CO2), nitrogen (N2) and water (H2O) harmless substances. The three-way catalyst is mainly composed of a coated carrier and a metal shell. At present, the typical three-way catalyst coating is palladium-rhodium double-coating technology, in which the palladium layer is mainly composed of activated alumina with a large specific surface area, thermal shock-resistant cerium-zirconium composi...

Claims

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Application Information

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IPC IPC(8): B01J23/63B01D53/94B01D53/62B01D53/56B01D53/72
CPCY02T10/12Y02A50/20
Inventor 赵德鹏岳军金炜阳王卫东贾莉伟浦琦伟郝士杰徐岘王家明王燕
Owner WUXI WEIFU ENVIRONMENT PROTECTION CATALYST
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