The Study Of Synthesis And Performance Of Oxygen Electrode And Hydrogen Evolution Catalysts Based On Carbon

Zinc-air batteries,fuel cells and water splitting systems have attracted increasing attention because of their potential application for solving energy problems.And the oxygen electrode reaction or hydrogen evolution reaction is the key reaction for above mentioned renewable energy technologies.However,the dynamic process of these electrochemical reactions is sluggish,leading to the inefficiency of these energy technologies.Up to now,the Pt noble metal and RuO2 and IrO2 remain the most efficient electrocatalyst for ORR,HER and OER.However,the high cost of these precious metal is not conformity with the requirement of sustainable development of human society.Therefore,developing low cost and highly active electrocatalyst has become important.And metal-free catalysts is regarded as the promising altenative to noble metal-based catalyst,and such material with optimized nanostructure and composition would be of good performance.In this paper,based on heteroatom-doped carbon material,the highly active catalysts for oxygen electrode and hydrogen evolution have been designed and synthesized.(1)We developed a porous N,O co-doped carbon cloth as an efficient metal-free bifunctional catalyst(N,O-CC)for ORR and OER,which was obtained by pyrolysis of a carbon cloth coated with polydopamine.The N,O co-doped carbon cloth possessed rich microporse,large specific surface area and high hydrophilicity.The optimized N,O-CC bifunctional catalyst exhibited excellent electrocatalytic activities for ORR with half-wave overpotential of 0.85 V and OER with potential of 1.63 V in a current density of 10 mA cm-2.More importantly,the bifunctional catalyst showed good durability.Besides,the rechargeable zinc-air battery based on the bifunctional catalyst exhibited good charge-discharge performance and stability,showing promising application in advanced renewable energy devices.(2)We also developed a three-dimensional porous N,P co-doped carbon nanosheets(N,P-3DPS)as an efficient metal-free hydrogen evolution reaction(HER)catalyst.Typically,a mixture of critic acid,urea and phosphoric acid was pyrolyzed in high temperature.The obtained N,P-3DPS possessed rich porosity,large specific surface area,abundant N,P co-doping and 3D nanostructure.The optimized N,P-3DPS catalyst exhibited good electrocatalytic activity for HER with a low overpotential of 310 mV at a current density of 10 mA cm-2.In addition,the N,P-3DPS catalyst showed excellent stability.Therefore,the N,P-3DPS is an efficient metal-free electrocatalyst for HER.