Synthesis Of N-doped Carbon Material And Study On Their Catalytic Performance For Oxygen Reduction Reaction

Fuel cells have been considered as a kind of new clean green energy technology because they have many advantages such as high energy conversion effience, good environmental affinity, high energy density, fast starting speed, noiseless and so on as not being restricted by carnot cycle. However, owing to the lower kinetics and larger overpotential of oxygen cathode for fuel cells, oxygen reduction reaction(ORR) is extremely slow. At present, Pt/C catalyst have been thought to become the best ORR catalyst. But platinum is a kind of earth-scarce noble and expensive metals. In order to overcome these shortcomings, seeking low price and high oxygen reduction activity with stability non-noble metal catalysts to replace Pt/C is the feasible way of finally realizing the large-scale commercial application.Therefore, the purpose of this paper is to explore the new synthetic methods and prepare high graphition and high oxygen reduction activity carbon nitrogen material as catalyst of fuel cell cathode oxygen reduction reaction by choosing cheap and easy to raw material. The major contents can be summarized as follow:(1) We choose cheap commercial cationic resin D113 as carbon source with acid pretreatment, Fe Cl2·4H2O as exchanger, glycine as nitrogen source, and four different nitrogen carbon materials was prepared by the quality of different carbon and nitrogen ration. By HRTEM、XRD and XPS characterization, we discovered the Fe Cl2 can greatly improve the graphitization degree of carbon material. But nitrogen content and oxygen reduction activity is not a certain proportion relation. At the same time, we summed up that the Valley-N is a kind of ORR N type which will help to improve the catalytic activity.(2) Using different exchanger: Fe Cl2·4H2O and Ni(Ac)2·4H2O as exchanger, glycine as nitrogen source, we prepared eight different carbon and nitrogen carbon materials. Through the analysis of various characterization methods, we found that the existence of metal can greatly increase the oxygen reduction activity of materials. The preparation of different metal catalytic graphitization of carbon materials have different morphology and the contribution of oxygen reduction is not the same for different materials.(3) Studying the influence of different nitrogen source: Co Cl2·6H2O(0.45M) as exchanger, we study the influence of different nitrogen source and doping methods and sequence under the glycine and NH3 as nitrogen source. By analysis, it proved that the catalyst has high catalytic ability and activity of oxygen reduction reaction. The catalyst shows the best electrochemical acticity from the preparation of catalytic graphitization of carbon materials by Co salts, the first glycine 900℃ doping N and then in preparation of NH3 950℃ heat treatment with N catalyst.