Method for preparing foam silver catalyst based on supercritical carbon dioxide foaming technology

Abstract

The invention provides a method for preparing a foamed silver catalyst based on a supercritical carbon dioxide foaming technology. The method comprises the following steps: plasticizing and modifyingpolyvinyl alcohol, preparing a PVA / AgNO3 composite plate by adopting a mould pressing method, preparing a PVA / AgNO3 composite foam material by adopting a supercritical carbon dioxide kettle pressure foaming method, and performing in-situ solid-state reaction on the obtained composite foam material, thereby obtaining the foamed silver catalyst. According to the invention, process conditions are optimized and combined; the foam pore structure is optimized, so that the foamed silver catalyst with characteristics of good catalytic efficiency and certain mechanical strength is obtained after the in-situ solid phase reaction, the foam pore size distribution of the foamed silver catalyst prepared through the method is uniform, the product is pure, and the catalytic performance is significantly superior to that of the similar products on the market.

Description

technical field [0001] The invention belongs to the technical field of porous foamed metal catalysts, in particular to foamed silver catalysts, in particular to a method for preparing foamed silver catalysts based on supercritical carbon dioxide foaming technology. Background technique [0002] As the demand for metal lightweight materials has increased in recent years, the research on metal foams has become more and more extensive. Silver foam is a new type of functional material. Because it combines many characteristics of foam and metallic silver, it not only has the advantages of high porosity, low density, high specific surface area, but also has excellent antibacterial, electrical and thermal conductivity, etc. performance. Silver foam is widely used in the fields of catalysis, sensing, heat dissipation and heat storage, electromagnetic shielding, sound absorption and noise reduction, and antibacterial. Among them, the use of foamed silver as a catalyst has good prac...

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Problems solved by technology

However, the main disadvantage of the method disclosed above is that it is difficult to control the shape of the cells, and the size of the prepared cells is large and the distribution is uneven, so it is difficult to obtain PVA / AgNO with stable quality. 3 Composite foam, and then will affect the quality and catalytic performance of the silver foam that makes to a great extent; In addition, in order to make polyvinyl alcohol cross-linked and form gel network structure, include adding chemical cross-linking agent or developing in the above-mentioned technical scheme The technical content of the foaming agent, so the prepared silver foam inevitably has a certain amount of residue, which affects the quality of the catalyst and product performance

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