Palladium-charcoal catalyst as well as preparation method and application thereof

Abstract

The invention provides a preparation method of a palladium-charcoal catalyst and further provides the palladium-charcoal catalyst prepared by using the preparation method and application of the palladium-charcoal catalyst. Compared with the prior art, palladium ions which are already adsorbed to a carrier are subjected to in-situ reduction through electrochemical in-situ reduction; compared with aconventional method that a reducing agent is added or electrochemical deposition is implemented, the preparation method is rapid in reduction speed, and the metal palladium takes the shape of sheetsand has a large contact area with the carrier, so that migration and dropping of the palladium metal can be well prevented, and the catalyst is high in stability, high in palladium atom utilization rate and good in catalysis performance; and meanwhile, a high conversion rate and yield can be achieved without adding other metals into the catalyst, and problems of separation and palladium metal recycling caused by conventional preparation methods can be solved.

Description

technical field [0001] The invention relates to the technical field of catalysts, in particular to a palladium-carbon catalyst and its preparation method and application. Background technique [0002] Palladium-based catalyst is a general-purpose catalyst with a wide range of uses and good performance. It has high catalytic activity and selectivity. Hydrogen and catalytic cracking. The palladium carbon catalyst loads the precious metal palladium on the activated carbon, the active palladium is distributed on the surface of the carrier carbon, and the palladium crystals inside help to improve the active agent life of the catalyst. [0003] The preparation of palladium-carbon catalyst generally includes pretreatment of carbon support, impregnation of palladium-containing solution and reduction of palladium. Wherein, the reduction of palladium can be reduced by a chemical reducing agent, or the palladium ions dissociated in the electrolyte can be reduced and deposited by elec...

AI Technical Summary

Problems solved by technology

However, during the reduction process of chemical reducing agents, palladium nanoparticles tend to aggregate, and the agglomeration phenomenon is more serious, which affects its catalytic activity; the agglomerated palladium nanoparticles are very easy to detach, and the stability is poor, resulting in the loss of precious metal palladium; the formed palladium nanoparticles are basically Surrounded by Pd(111) crystal face, its crystal face is single, and its catalytic performance is poor

In the preparation of electrochemical plating deposition, the formation of palladium metal crystals includes the migration and reduction of metal ions, the nucleation of metal atoms, and the growth of nuclei. The migrated metal ions will be reduced to the nucleated metal atoms, resulting in the formation of The palladium metal atoms in the core grow up and aggregate to form large-sized granular nanoparticles, so that most of the atoms are wrapped inside the nanoparticles, making the utilization rate of metal atoms low, and the contact area between the granular nanoparticles and the carrier is small, which is easy to cause Shedding of nanoparticles, resulting in poor catalyst stability and loss of palladium metal

[0004] In addition, traditional palladium-carbon catalysts will inevitably introduce or generate other substances during the preparation process, which will cause the separation and recovery of reaction products and additives or by-products, especially palladium metal is an expensive noble metal, which will cause cost. Increase

[0005] In summary, the preparation method of traditional palladium-carbon catalysts is relatively complicated, and it faces the problems of easy agglomeration, easy falling off, poor stability, low utilization rate of palladium atoms, poor catalytic activity and difficult recovery.

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