Preparation method and application of supported noble metal catalyst

A noble metal catalyst, supported technology, applied in the direction of metal/metal oxide/metal hydroxide catalyst, chemical instrument and method, physical/chemical process catalyst, etc. Complex precious metal process and other issues, to achieve the effect of reducing the sintering probability of precious metals, reducing the sintering probability, and outstanding anti-aging ability

Active Publication Date: 2015-12-16
SINOCAT ENVIRONMENTAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Sichuan University uses drying and calcination to solidify precious metals. However, during the drying process, some precious metal ions are not adsorbed on the carrier due to electrostatic attraction, but are free in the excess solution. As the drying process progresses, water migrates to the surface of the carrier and is accompanied by With the migration of noble metal ions, noble metals will accumulate on the surface of the carrier, resulting in a decrease in the dispersion of the catalyst
The process of curing precious metals by calcination is complex, high energy consumption, and the migration of precious metal ions in the drying process leads to a decrease in the aggregation and dispersion of precious metals and a decrease in catalytic activity
[0007] The above methods for preparing supported catalysts have certain limitations, so it is imperative to develop a new method for preparing supported noble metals.

Method used

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  • Preparation method and application of supported noble metal catalyst
  • Preparation method and application of supported noble metal catalyst

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preparation example Construction

[0035] A preferred embodiment of the present invention, the preparation method of supported noble metal catalyst comprises the following steps:

[0036] (1) Preparation of noble metal precursor solution.

[0037]Weigh the corresponding mass of soluble precious metal raw material, and add 0.5-5 times the volume of solvent of incipient wetness water pore volume. Adjust the pH at -0.5 to 12. Add a protective agent with an amount of 0-10 times the precious metal (based on the molar mass of the monomer). Stir well.

[0038] (2) The precious metal and the carrier are evenly mixed.

[0039] Add the precursor solution to the carrier in spray form or add the carrier to the precursor solution. Stir at 0-90°C for 0.5-8h.

[0040] (3) Add protective agent.

[0041] Weigh the protective agent (calculated as monomer) that is 0 to 10 times the stoichiometric amount of the precious metal and dissolve it in the suspension that has been uniformly mixed in step (2). Stir at 0-90°C for 0.5...

Embodiment 1

[0052] Use dilute ammonia water to adjust the pH of the palladium nitrate solution to 1.0, add deionized water to make the volume of the precursor solution 0.6 times the volume of the water pores of the carrier, add it to the Ce / Zr carrier in the form of a spray, stir rapidly at room temperature until uniform, and statically set for 2h. Weigh the PVP with a metering ratio of 1:1 and dilute it to 0.2 times the volume of the water pores, then add it in the form of a spray and stir it quickly until it is uniform, and let it stand for 0.5h. Add 0.2 times the volume of methanol in the water pores, add it in the form of a spray and stir it quickly until it is uniform, and let it stand for 2h. After a part was dried at 110°C for 2 hours, it was calcined at 550°C for 2 hours, and a sample was taken to test the dispersion degree of the precious metal, which was recorded as the dispersion degree A0. Part of it was directly added with deionized water and binder, and ball milled for 15 m...

Embodiment 2

[0054] Prepare 5g / L palladium nitrate solution, add dilute ammonia water dropwise to control the pH at 1.0. Add Ce / Zr carrier, stir in 80°C water bath for 4h. Add PVP (measurement ratio 1:1), and stir in a water bath at 80°C for 1h. Then add methanol with a metering ratio of 1:4, and stir in a water bath at 80°C for 4h. After a part was dried at 110°C for 2 hours, it was calcined at 550°C for 2 hours, and a sample was taken to test the dispersion degree of the precious metal, which was recorded as the dispersion degree A0. Part of it was directly added with deionized water and binder, and ball milled for 15 minutes to obtain a coating solution with a solid content of 40%. The coating solution was coated on the cordierite substrate, and the remaining slurry was air-dried and roasted to test the degree of dispersion, which was recorded as the degree of dispersion B0. The cordierite substrate coated with the coating solution was dried at 120° C. for 2 h, and calcined at 550° C...

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Abstract

The invention discloses a preparation method of a supported noble metal catalyst. According to the method, a precursor solution is prepared from noble metal used as an active ingredient and evenly mixed with supporters; a liquid reducer is added, noble metal ions which are adsorbed or ionized on surfaces or in holes of the supporters are reduced, the noble metal is applied to the supporters in the reduced state, and mixed slurry is obtained; a cordierite matrix or a metal matrix is coated with the mixed slurry, and the supported noble metal catalyst is obtained through calcination; the noble metal is one or more of Pt, Pd, Rh, Au, Ag and Ru and serves as a raw material in forms of nitrate, chloride and an organic complex. Compared with the prior art, the method has the advantages that the noble metal is already reduced and solidified in the supporting process, and conditions that the dispersity of the noble metal is reduced and the activity is reduced due to the fact that the noble metal is gathered on the surfaces of the supporters due to migration caused by water migration in the drying process can be avoided. Besides, the dispersity of the noble metal on the supporters is good, and the sintering probability of the noble metal in the high-temperature ageing process is decreased.

Description

technical field [0001] The invention relates to a preparation method of a supported noble metal catalyst, in particular to the reduction and solidification technology of the noble metal in the supported technology and the direct preparation of a catalyst coating from a catalyst suspension, which is applied to an automobile exhaust catalyst. Background technique [0002] Supported noble metal catalysts are mainly applied on the carrier in the form of nitrate, chloride or amine-modified organic complex solution of noble metal to remove excess water, and then decompose at high temperature to form noble metal oxides fixed on the carrier. [0003] In 2006, Nippon Automobile Co., Ltd. proposed in the patent CN101300076A to use an organic complex capable of coordinating with noble metals to be mixed with a noble metal solution to form a noble metal organic complex. The noble metal is reduced and applied to the carrier, and calcined to obtain the catalyst. In this method, the noble...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/63B01D53/94F01N3/28
Inventor 王瑞芳李云廖传文范婷婷龚国恒吴冬冬
Owner SINOCAT ENVIRONMENTAL TECH
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