Chitosan-modified activated coke in-situ loaded nano-gold catalyst and its preparation method

Abstract

The invention discloses a chitosan-modified activated coke loaded with nano-gold catalyst in-situ and a preparation method thereof. The chitosan-modified activated coke loaded with nano-gold catalyst in-situ includes activated coke, chitosan and nano-gold particles. The activated coke The surface modified chitosan forms a chitosan / activated coke complex, and the chitosan / activated coke complex is loaded with gold nanoparticles. The preparation method includes preparing a chitosan / active coke composite and loading nano-gold on the chitosan / active coke composite. The catalyst of the present invention has the advantages of good dispersion of nano-gold particles, high mechanical strength, good catalytic activity, good stability, etc. It is a new type of supported nano-gold catalyst and has high application value and wide application range. The preparation method has the advantages of simple preparation process, easy operation, cheap raw materials, short production cycle, low production cost, green and environmental protection, etc. It can realize large-scale preparation at normal temperature and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of nano-metal catalyst preparation, and relates to a chitosan-modified activated coke in-situ loaded nano-gold catalyst and a preparation method thereof. [0002] technical background [0003] In the existing nano-gold catalyst, due to the small particle size and high surface activation energy of the nano-gold, it is easy to agglomerate, so that the reaction activity is significantly reduced. Based on the above problems, researchers try to load nano-gold particles on the carrier to improve the activity and stability of the catalyst, among which carbon materials such as carbon nanotubes, carbon nanofibers, graphene (graphene oxide), mesoporous carbon, etc. are often used as Nanogold carrier materials, but these carrier materials have problems such as high cost, low mechanical strength, and underdeveloped pore structure, and the acquisition methods of these carbon materials are relatively complicated and diffic...

AI Technical Summary

Problems solved by technology

Based on the above problems, researchers try to load nano-gold particles on the carrier to improve the activity and stability of the catalyst, among which carbon materials such as carbon nanotubes, carbon nanofibers, graphene (graphene oxide), mesoporous carbon, etc. are often used as Nanogold carrier materials, but these carrier materials have problems such as high cost, low mechanical strength, and underdeveloped pore structure, and the acquisition methods of these carbon materials are relatively complicated and difficult to obtain. The weak interaction force of gold makes it challenging to load nano-gold. For example, nano-gold is easy to lose, the catalyst activity drops significantly, and the cycle stability is not high. Therefore, can the binding force between nano-gold and carbon support be further enhanced? It is one of the issues that are currently concerned about supported nano-gold catalysts.

In addition, the existing preparation methods of supported nano-gold catalysts include impregnation method, deposition-precipitation method, co-precipitation method, chemical vapor deposition method, etc. These methods have the following disadvantages: incomplete loading of nano-gold catalysts, poor repeatability of the preparation process, and easy Affected by the solvation effect and the cluster effect of metal components, resulting in poor dispersion of gold nanoparticles, unstable catalyst structure (poor stability), high amount of precious metals, and the addition of chemical reagents such as sodium borohydride and hydrazine during the preparation process , and these chemical reagents will cause secondary pollution to the environment, which does not meet the theme of green chemistry

In addition, the existing deposition-precipitation method, impregnation method and other methods are difficult to achieve high dispersion of gold nanoparticles on carbon support materials.

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