N-Doped Modification Of Carbon Materials And Synthesis Of Supported Cobalt And Manganese Oxide

The oxygen reduction reaction (ORR), responding to increasing energy demands, gain more attention for wide applications such as fuel cells. As the heart of issue, promising catalysts are still urgently needed to overcome the impediments of sluggish reaction kinetics of ORR. Despite platinum and its alloy being considered the best catalysts for ORR, the high cost of Pt and its decline activity have set back their wider application. As result, modified carbon materials and metal oxide catalysts with low cost and considerable activity arise as required.The hydrothermal was adopted to realize the nitrogen doping to different carbon materials (Graphitized Carbon Blacks, Vulcan-72XC, CNTs, graphene) with various nitrogen sources (ammonia, ethylenediamine, hydrazine). Nitrogen doping was confirmed by elements analysis and XPS, and dramatic hollow core structure was detected by TEM. The N-doped carbon materials with ammonia as dopants showed higher catalytic activity, which was performed further investigation. The properties of N-doped carbon blacks changed along with various hydrothermal temperatures.Probable intermediates was detected and hollowing mechanism was deduced that stacking defects originated from surface oxidation and the reaction between functional groups and ammonia provided outdiffusion driving force for interior carbon atoms which cause atom diffusion and arrangement of graphitic sheet. Oxygen reduction catalytic activity and durability was inspected, proving this N-doped hollow carbon material as a durable and practical catalyst.Here, we synthesized a hybrid material Consisting of Co3O4(-2-3nm in size) and reduced graphene oxide (R-CO3O4/GO) via NaBH4reduction, which was performed N-doping modification by hydrothermal with ammonia. Morphology can be modulated by hydrothermal temperature and nitrogen content can be changed through addition amount of NaBH4. Modified catalyst (H-CO3O4/N-GNS) shows superior electrochemical performance. Citric acid Complexing reduction method was adopted to load Mn3O4nanoparticles on Co3O4of H-CO3O4/N-GNS, realizing supported model N-doped GNS supported double metal oxide and the special structure was proved. This composite catalyst showed better durability. Electrochemical test and XPS were used to uncover the interfacial interaction and synergistic effect among nanoparticles and carbon materials, which is probably responsible for performance improvement.