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Exhaust gas purification catalyst and method for producing exhaust gas purification catalyst

A technology for exhaust purification and catalysts, which is applied in the field of exhaust purification catalysts, and can solve problems such as reduced catalytic activity, instability, and difficulty in maintaining catalytic activity

Inactive Publication Date: 2007-12-12
NISSAN MOTOR CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, although small noble metal particles with a particle size of less than 10 nm have high catalytic activity, they are very unstable due to their high reactivity and large surface energy.
At this time, the platinum aggregates and the particle size becomes larger, so the catalytic activity decreases
In this way, in the current exhaust gas purification catalyst, even if the particle size of platinum is small when the catalyst is produced, the particle size cannot be maintained, and it is difficult to maintain the catalytic activity.

Method used

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  • Exhaust gas purification catalyst and method for producing exhaust gas purification catalyst
  • Exhaust gas purification catalyst and method for producing exhaust gas purification catalyst
  • Exhaust gas purification catalyst and method for producing exhaust gas purification catalyst

Examples

Experimental program
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Effect test

Embodiment 1

[0062] (embodiment 1) prepares Pt0.3% / CeO 2 20%-Al 2 o 3 powder

[0063] First, cerium acetate was added to alumina dispersed in water so that the CeO 2 is 20wt%. Then, it was stirred for 2 hours, dried at 120° C. for a whole day and night, and then fired at 600° C. in air for 2 hours. The stirred sample was dispersed in water, and tetraammine platinum hydroxide salt was put into it. Then, it was stirred for 2 hours, dried at 120° C. for a whole day and night, and then fired at 400° C. in air for 1 hour. The sample obtained by firing was dispersed in water, and cerium acetate and aluminum nitrate were added thereto. Then, after stirring for 2 hours, it dried at 120 degreeC for a whole day and night, and baked at 400 degreeC in air for 1 hour, and obtained the target sample.

Embodiment 2

[0064] (Example 2) Manufacture of Pt0.3% / CeO 2 20%-Al 2 o 3

[0065] In Example 2, using Ce-Al 2 o 3 as alumina. First, the peak integral intensity of the Ce(200) plane obtained by X-ray diffraction analysis relative to the peak integral intensity of the Ce(111) plane is greater than 0.6. 2 20%-Al 2 o 3 Dispersed in water. Tetraammine hydroxide platinum salt was put into this dispersion liquid. This was stirred for 2 hours, dried at 120° C. for a whole day and night, and then fired at 400° C. in air for 1 hour. The obtained sample was dispersed in water, and cerium acetate and aluminum nitrate were added thereto. Then, it was stirred for 2 hours, dried at 120° C. for a whole day and night, and then fired at 400° C. in air for 1 hour to obtain the target sample.

Embodiment 3

[0066] (Example 3) Manufacturing Pt0.3% / CeO 2 20%-Al 2 o 3

[0067] In Example 3, using Ce-Al 2 o 3 as alumina. First, the peak integral intensity of the Ce(200) plane obtained by X-ray diffraction analysis relative to the peak integral intensity of the Ce(111) plane is greater than 0.6. 2 20%-Al 2 o 3 Dispersed in water. Add dinitrodiamine platinum salt to the dispersion, and then add NaBH for reducing Pt. 4 , stirred for 2 hours, dried at 120°C for a whole day and night, and then fired at 400°C in air for 1 hour. The obtained sample was dispersed in water, cerium acetate and aluminum nitrate were put into it, and then ammonia water was put into it. Then, it was stirred for 2 hours, dried at 120° C. for a whole day and night, and then fired at 400° C. in air for 1 hour to obtain the target sample.

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Abstract

An exhaust gas purification catalyst 1 which comprises a composite compound 2 prepared by dispersing a metal selected from among Al, Ce, La, Zr, Co, Mn, Fe, Mg, Ba and Ti uniformly into an oxide selected from among Al2O3, ZrO2 and CeO2, and a noble metal 4 being selected from among Pt, Pd and Rh, carried on a metal compound 3 and covered with the composite compound 2.

Description

technical field [0001] The present invention relates to an exhaust gas purification catalyst and a method for producing the exhaust gas purification catalyst, and more particularly to an exhaust gas purification catalyst for purifying exhaust gas discharged from an internal combustion engine. Background technique [0002] Exhaust gas restrictions on automobiles are expanding globally. Therefore, alumina (Al 2 o 3 ) and other carrier-based three-way catalysts are used to purify hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO x ). [0003] Since the reaction using the noble metal is a contact reaction in which the reaction occurs on the surface of the noble metal, the catalytic activity of the noble metal is roughly proportional to the surface area of ​​the noble metal. Therefore, in order to obtain the maximum catalytic activity from a small amount of noble metal, it is preferable to prepare noble metal particles with a small particle size and a high specific ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/63B01J23/656B01J23/89B01J23/58B01J37/16B01D53/94
CPCB01J23/6562B01J33/00B01J23/63B01J37/0205B01J37/0207B01D53/945B01J37/024B01J23/8906Y02T10/22B01J35/006B01J23/464B01J23/894B01J37/16Y02T10/12B01J23/56B01D53/94
Inventor 中村雅纪菅克雄若松广宪白鸟一幸安田博文青山诚
Owner NISSAN MOTOR CO LTD