Supported silver-carbon catalyst for salt electrolysis and preparation method thereof

Abstract

The invention discloses a supported silver-carbon catalyst for salt electrolysis, which is characterized by being solid powder. Silver particles with the particle size being 3-10nm are loaded on the surface of acidified carbon black particles through uniform dispersion, the silver loading factor ranges from 40 percent to 400 percent, and the mass ratio of the silver and the acidified carbon blackparticles is 0.4:1-4:1. The preparation method adopts chemical reduction and comprises: pouring silver ammonia solution and hydroxide sodium solution in sequence into a reaction system which consistsof glycol and acidified carbon black, mixing well, condensing and refluxing at the certain reaction temperature to obtain the reaction product, black solution, and finally obtaining black solid powder through centrifugation or filtration washing and drying.

Description

technical field [0001] The invention relates to a high-efficiency catalyst for salt electrolysis suitable for chlor-alkali industry, in particular to a supported silver-carbon catalyst and a preparation method thereof. Background technique [0002] The caustic soda production processes in the world mainly include ionic membrane method, diaphragm method and mercury method, and a small amount of causticization method. At present, the ionic membrane method has successively replaced the mercury method, the diaphragm method, and the causticizing method, and has become the preferred method for caustic soda production. The ionic membrane method still uses the hydrogen evolution cathode (nickel mesh + active coating), and its electrolytic chemical reaction formula is: 2NaCl+2H 2 O-→Cl 2 +2NaOH+H 2 , its theoretical electrolysis voltage is 2.24V, which requires a lot of energy. The gas diffusion electrode is used in the ion membrane electrolyzer to replace the currently used activ...

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Problems solved by technology

The colloid of silver exists following problem as the catalyzer on the catalytic layer: 1) the colloid of silver must be deposited in the solution with stabilizers such as amino acid, polyvinylpyrrolidone, polyvinyl alcohol; The introduction of impurities due to the stabilizer affects the activity of the catalyst; 2) In the preparation process of the catalyst layer, after hot pressing, most of the stabilizer decomposes at high temperature, and the silver colloid without the protection of the stabilizer will inevitably agglomerate, and the particle size 3) In the process of electrolyzing salt water, since there is no binding force between the silver colloid and carbon black, as the electrolysis time increases, the silver colloid will inevitably be lost and fall into the electrolyte, The life of the gas diffusion electrode is affected; 4) Since there is no binding force between the silver colloid and the carbon black, the electron transport between the silver particles and the carbon particles will be affected to a certain extent

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