| Low temperature fuel cells(LTFCs) is considered as one of the most promising candidates for portable power sources due to their high energy density, easiness in fuel storage and supply and low environmental pollution. As one of the key materials of low temperature fuel cells, electrocatalysts still hinder the commercialization of fuel cells due to its limited activity and stability, high price and poor poison tolerance.Firstly, polyhedral Pd-Pt nanocrystals with well-defined morphology were obtained with ammonia as complex agent to control the nucleation and growth process, as well as using reduced graphene oxide(rGO) as the substrates to support and anchor the Pd-Pt nanocrystals. The effect of the Pd/Pt ratio and the surface states of substrate on the morphology, activity and poison tolerance was investigated by TEM and HRTEM characterizations. The result indicates that based on the rich active facets derived from well-defined polyhedral morphology, the Pd-Pt nanocrystals exhibit high catalytic activity for oxygen reduction reaction and excellent methanol tolerance.Secondly, composite catalysts(MnS-NT@r GO) with novel structure were synthesized based on the excellent redox reaction of manganese sulfide and the appropriate adsorption/desorption for oxygen on reduced graphene oxide. Electrochemical measurement shows that the composite catalysts hold superior activity and stability for oxygen reduction reaction than commercial TKK Pt/C, and are inert to methanol oxidation reaction.Finally, porous carbons with dense and distributed evenly pores were prepared using the soft, rich in nitrogen heteroatom eggplant as precursor, activating with potassium hydroxide. The effect of metal catalyst and added nitrogen on the nitrogen content and the type of C-N bonds was investigated by XPS characterizations. The result reveals that the metal catalyst has a effect on nitrogen fixation, the nitrogen content of carbons will increase with the addition of nitrogen. |
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