Preparation Of Transition Metal/Nitrogen-Doped Carbon Material And The Study On Their Electrocatalytic Performance

Currently,problems of energy shortage and environmental pollution are increasingly prominent,so it is urgent task to find clean and sustainable energy sources.Fuel cells are considered as one of the most promising alternatives to traditional energy sources due to their low cost,environmental friendliness,and high efficiency.Oxygen reduction reaction（ORR）is the cathode reaction in fuel cells,which requires the catalyst to improve its reaction efficiency because of slow kinetics.At present,Pt-based materials are considered to be the most effective ORR catalysts,but their high cost and poor stability have limited their wide application.Therefore,the development of more efficient non-noble metal catalysts that can replace Pt-based materials has become a hot research direction.（1）Novel iron and cobalt co-doped carbon materials（Fe/Co-N-C）with high electrocatalytic activity for ORR were successfully fabricated by pyrolyzing the mixture of lactone tofu,ferrous（II）chloride and cobalt（II）chloride.The structure and properties of the materials were analyzed by thermogravimetric analysis,scanning electron microscopy,transmission electron microscopy,X-ray diffraction and other characterization methods.The electrocatalytic activity and stability of the Fe/Co-N-C materials in alkaline media were evaluated by cyclic voltammetry,linear sweep voltammetry and chronoamperometry.Among the Fe/Co-N-C materials,Fe/Co-N-C₇₀₀（3）has the best performance of electrocatalytic activity.（2）Zinc salt,aniline and acetylene black are used as the main raw materials to prepare a new type of Zn-containing carbon material(Zn/N-OC₈₀₀)as an ORR catalyst.The structure and properties of the Zn/N-OC₈₀₀ were studied by scanning electron microscopy,transmission electron microscopy,X-ray diffraction and other characterization methods.The electrocatalytic activity and stability of the Zn/N-OC₈₀₀in alkaline media were evaluated by cyclic voltammetry,linear sweep voltammetry and chronoamperometry.The results show that high conductivity,high content of pyridinic-N and graphitic-N make Zn/N-OC₈₀₀ has good electrocatalytic activity.（3）Iron and nitrogen co-doped carbon materials(Fe/N-C_CM-T)with high electrocatalytic activity for ORR were successfully fabricated from pyrolyzing the mixture of Fe salt,chitosan and melamine.The structure and properties of Fe/N-C_CM-800 were characterized by a series of methods,and the electrocatalytic activity and stability of the Fe/N-C_CM-800 in alkaline media were evaluated by cyclic voltammetry,linear sweep voltammetry and chronoamperometry.The results show that melamine not only improves the nitrogen content of Fe/N-C_CM-800,but also makes Fe/N-C_CM-800has uniform nanotube structure,thus Fe/N-C_CM-800 has good electrocatalytic activity.