Preparation method for three-way catalyst coated with two layers

A three-way catalyst, catalyst technology, applied in catalyst activation/preparation, chemical instruments and methods, heterogeneous catalyst chemical elements, etc., can solve the problems of migration and coking, grain growth, affecting catalytic performance, etc. performance, improve stability

Inactive Publication Date: 2019-11-05
WUXI WEIFU ENVIRONMENT PROTECTION CATALYST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, the noble metal active components are prone to grain growth, migration and coking during the high temperature aging process, which seriously affects the catalytic performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] A kind of preparation method of the three-way catalyst of double-layer coating comprises the following steps:

[0022] a. Mix 800g of cerium nitrate, 1300g of zirconium nitrate and 2000g of deionized water, and stir to dissolve. Then add 37.5g of platinum nitrate (containing 10mass% Pt) and 200g of neodymium nitrate in sequence, add 5g of EDTA after stirring well, adjust the pH of the solution to 10 with ammonia water, heat in a water bath at 90°C and stir to fully volatilize the water and age it overnight , to get a wet gel;

[0023] b. Dry the wet gel in an oven at 120°C for 8 hours, then put it into a muffle furnace to program the temperature up to 550°C at a rate of 10°C / min and keep it roasted for 2 hours, then grind the catalyst to particle size 80μm to get catalyst powder;

[0024] c. Take 192g of catalyst powder and add it into 1200g of deionized water. After fully stirring, add 308g of La 2 o 3 -Al 2 o 3 (La 2 o 3 with Al 2 o 3 The mass ratio is 1:99)...

Embodiment 2

[0027] A kind of preparation method of the three-way catalyst of double-layer coating comprises the following steps:

[0028] a. Mix 500g of cerium nitrate, 1600g of zirconium nitrate and 2000g of deionized water, and stir to dissolve. Then add 75g platinum nitrate (containing 10mass% Pt) and 200g lanthanum nitrate successively, add 12g citric acid after fully stirring, adopt ammoniacal liquor to adjust the pH of the solution to 8, heat in a water bath at 65° C. and stir to make the moisture fully volatilize and age overnight. get a wet gel;

[0029] b. Dry the wet gel in an oven at 100°C for 8 hours, then put it into a muffle furnace to program the temperature up to 500°C at a rate of 25°C / min and keep it roasted for 2 hours, then grind the catalyst to particle size 60μm to get catalyst powder;

[0030] c. Take 100g of catalyst powder and add it into 1200g of deionized water, stir well and add 400g of La 2 o 3 -Al 2 o 3 (La 2 o 3 with Al 2 o 3 The mass ratio is 1:99...

Embodiment 3

[0033] A kind of preparation method of the three-way catalyst of double-layer coating comprises the following steps:

[0034] a. Mix 1000g of cerium nitrate, 1100g of zirconium nitrate and 2000g of deionized water, and stir to dissolve. Then add 21g of platinum nitrate (containing 10mass% of Pt) and 80g of yttrium nitrate successively, after fully stirring, add 2g of citric acid, and adjust the pH of the solution to 9 with ammonia water. Heat in a water bath at 90°C and stir to fully evaporate the water and age overnight to obtain a wet gel;

[0035] b. Dry the wet gel in an oven at 180°C for 5 hours, then put it into a muffle furnace to program the temperature up to 800°C at a rate of 20°C / min and keep it roasted for 1 hour, and grind the catalyst to particle size 20μm to get catalyst powder;

[0036] c. Take 180g of catalyst powder and add it into 1200g of deionized water. After fully stirring, add 320g of La 2 o 3 -Al 2 o 3 (La 2 o 3 、Al 2 o 3 The mass ratio is 1:...

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Abstract

The invention relates to a preparation method for a three-way catalyst coated with two layers. The preparation method comprises the following steps of preparation of wet gel, preparation of catalyst powder, coating of the platinum-containing coating layer and coating of the rhodium-containing coating layer. The Pt/CeZr catalyst powder prepared by adopting the method has high chemical composition uniformity, high purity and superfine performance, and the dispersibility of Pt active components can be improved; Pt and a carrier cerium and zirconium composite oxide have a strong metal-carrier interaction effect, in the high temperature ageing process, Pt-O and Pt-O-Ce bonds are formed, and the stability of high temperature ageing of the catalyst is greatly improved.

Description

technical field [0001] The invention relates to a preparation method of a double-layer coated three-way catalyst, which belongs to the technical field of catalyst preparation. Background technique [0002] The three-way catalyst for gasoline vehicles refers to the carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO x ) into harmless carbon dioxide (CO 2 ), water (H 2 O) and nitrogen (N 2 ) for automotive catalysts. With the continuous increase of the number of motor vehicles in our country, the pollutants of automobile exhaust have become the main source of urban air pollution, which not only causes great harm to human health, but also has great damage to the ecological environment. Therefore, all countries have enacted strict automobile exhaust emission regulations to limit the emission of gaseous pollutants. With the implementation of the "National VI" regulations approaching, higher requirements are put forward for the preparation of three-way catalysts. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/63B01J37/03B01J37/02B01D53/94
CPCB01J23/63B01J23/002B01J37/036B01J37/0215B01J37/0234B01D53/945B01D2258/01B01J2523/00B01J2523/31B01J2523/3706B01J2523/3712B01J2523/3718B01J2523/3725B01J2523/48B01J2523/36
Inventor 韩田朋李小明王德冰谢鼎峰浦琦伟孙亮潘其建韩婷婷马承艺王俊邱祎源饶婷王卫东张徐明岳军贾莉伟
Owner WUXI WEIFU ENVIRONMENT PROTECTION CATALYST
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