Study On Preparation And Properties Of Carbon-based Oxygen Reduction Catalysts

Up to now,platinum?Pt?and its alloys are the most effective catalysts for the cathodic oxygen reduction?ORR?of fuel cells.However,the large-scale application of these catalysts is limited by the disadvantages of high cost,easy poisoning and degradation,and limited reserves in the earth.Therefore,the research of carbon based catalysts with the advantages of anti poisoning and low cost has been widely concerned.In this paper,carbon based oxygen reduction catalysts for biomass and nitrogen doped iron-based carbide oxygen reduction catalysts were studied.The structure and catalytic oxygen reduction performance of these catalysts were studied.Through the exploration and research of this paper,the following conclusions are drawn:?1?A series of carbon based oxygen reduction catalysts with high surface area(294m² g^-1),good conductivity and high nitrogen content?9.4 at%?were prepared by hydrothermal one pot synthesis of soybean milk biomass and high performance graphene reduction type graphene oxide?rGO?intercalated oxygen reduction electrocatalyst?BDC/rGO-HT-NH₃?.Linear sweep voltammetry and other electrochemical tests showed that the initial potential of BDC/rGO-HT-NH₃ catalyst for oxygen reduction was only 0.11 V lower than that of commercial 20 wt%Pt/C catalyst,and the catalyst had good stability at the same time.The main reaction process of BDC/rGO-HT-NH₃ catalyst for oxygen reduction was four electron reaction.?2?In this paper,the homogeneous mixture of ferric chloride and melamine in different proportions was pyrolyzed directly at different temperatures to prepare the bamboo like fe-n-doped carbon nanotubes?Fe/N/C?.Cyclic voltammetry,linear sweep voltammetry and other electrochemical tests show that the N-doped Fe/N/C-20-750 catalyst has excellent orr activity,long-term operation stability and methanol toxicity resistance in alkaline and acid electrolyte.The main oxygen reduction reaction catalyzed by the catalyst is 4-electron reaction,which greatly reduces the formation of H₂O₂,the intermediate product of oxygen reduction.Fe and N in the doped CNTs are binary active centers,and their synergistic effect improves the electrocatalytic activity of the catalyst.The results of SEM and TEM show that the Fe/N/C-20-750 synthesized in situ has the active center structure of bamboo like carbon nanotubes wrapped with active metal,the cross network structure formed by carbon nanotubes and good graphitization can effectively improve the electronic transmission effect,at the same time,its large specific surface area and graded porous structure greatly increase the electrocatalytic active center,improve the oxygen diffusion and electrolyte separation The sub efficiency transfer greatly improves the electrocatalytic oxygen reduction performance of the material.This paper mainly studies and reports graphene-doped biomass-derived carbon-oxygen reduction catalyst and melamine-derived carbon-coated metal oxygen reduction catalyst.Both materials have good catalytic oxygen reduction performance,which is the follow-up new carbon-based oxygen reduction.The development of the catalyst laid the foundation.