A kind of co-n-c composite catalyst and its preparation method and application

Abstract

The invention discloses a Co-N-C composite catalyst. The Co-N-C composite catalyst comprises a Co and N codoped carbon nanoparticle and CNTs (Carbon Nanotube), and the Co and N codoped carbon nanoparticle grows on the surface of the CNTs to form a three-dimensional net structure. The Co-N-C composite catalyst takes chitosan as a carbon source and chitosan and urea as nitrogen sources, the CNTs areadded, the Co-N-C / CNTs composite catalyst is synthesized through an in-situ transformation method, the synergistic effect of the Co-N-C and the CNTs obviously strengthens the ORR dynamics of the Co-N-C, the composite catalyst is applied to an aluminum-air battery cathode material, the limiting current density is up to 5.3 mA cm<-2> and is equivalent to that of a commercial Pt / C electrode (5.2 mAcm<-2>); the Co-N-C nanoparticle grows on the surface of the CNTs to form the three-dimensional net structure, so that the composite catalyst is better in electric conduction and has a large specificsurface area, more electrochemical reaction active sites are achieved, the adsorption of molecular oxygen is promoted, the catalysis is further carried out to reduce the molecular oxygen, then the catalytic activity of the ORR (Oxygen Reduction Reaction) is obviously improved; the process method is simple, the cost is low, the requirement on equipment is not high, and the Co-N-C composite catalystis suitable for large-scale production.

Description

technical field [0001] The invention belongs to the technical field of electrocatalysis, and in particular relates to a Co-N-C composite catalyst and a preparation method and application thereof. Background technique [0002] With the continuous consumption of fossil energy, the continuous increase of energy demand and the enhancement of environmental protection awareness, all countries in the world have turned their attention to new energy sources, and the development of a low-cost, high-performance energy conversion and storage device has become the key. Rechargeable metal-air batteries have attracted widespread attention due to their simple preparation, low cost, excellent safety performance and environmental friendliness. In the field of metal-air batteries, the biggest bottleneck is the cathode material-oxygen reduction (ORR) catalyst. At present, most of the cathode materials of metal-air batteries use precious metals such as platinum carbon, ruthenium, iridium, etc., ...

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Problems solved by technology

[0003] So far, there are many types and methods of non-precious metal catalysts that can be developed. Among them, Co-N-C catalysts have high electrocatalytic activity and excellent anti-toxicity performance, which is a very potential low-cost ORR catalyst. Co and N co-doped carbon material catalysts have been proved to have excellent ORR catalytic activity, but as the reaction progresses, the catalytic activity decreases rapidly, and it is difficult to maintain the stability of the catalytic current. One of the important reasons is that the loss of Co leads to graphitization. The structure of C is unstable and the catalytic activity is reduced

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