The Systematic Study Of Synergistic Effect Of N-doped Carbon Based CoMn Oxide Composite For Bifunctional Oxygen Electrocatalyst

Although the development of regenerative energy(e.g.,solar power,wind power,hydroelectricity)has eased the energy crisis,these energy sources are still limited by some serious problems such as unstable energy output,low efficency and geographical restriction.To solve the growing energy problem,new technologies have been developed for energy generation and storage.United regenerative alkaline fuel cell(URAFC)are one of the promising energy systems due to its high conversion efficiency,regenerative and zero-emission properties.The key bottleneck for URAFC is the development of efficient bifunctional oxygen catalysts which act both as oxygen reduction reaction(ORR)catalyst and as oxygen evolution reaction(OER)catalyst.The noble metal Pt/IrO2 have long been regarded as the most efficient bifunctional oxygen catalyst.However,their prohibitively high cost and scarcity are disincentives for large-scale application.Therefore,there is a strong drive to develop the efficient,low-cost and robust bifunctional oxygen catalysts.A series of experiments have been performed to investigated the effect of metal doping,carbon support and nitrogen doping on the bifunctional activity of non-precious metal catalyst.This paper focus on the bifunctional activity of cobalt oxide and improve it with a series of promising strategies.At the same time,it have clarified the relationship of various factors which affect the bifunctional activity by constantly comparing the influence of them.The doping of manganese in cobalt oxide can effectively improve the bifunctional activity due to the modification of electronic structure.Beside that,the bifunctional activity of metal oxide is limited by the poor conductivity.It is a good strategy to select a conductive support for it.Among different carbon supports,carbon nanotube(CNT)with higher graphited degree which is more conducive to improving the bifunctional catalytic activity and stability of metal oxide.Finally,nitrogen elements doping in CNT can further improve the bifunctional catalytic activity and stability of the composite material.In this article,we have discussed the design strategy of N-doped carbon-based CoMn oxide for bifunctional catalyst in detail.Co2.25Mno.75O4/N-CNT exhibits the excellent ORR activity with the half-wave potential(E1/2)of 0.88 V and a E10(10mA/cm2)of 380 mV for OER.The bifunctional activity of CoMn oxide/NCNT is even better than Fe-N-C catalyst.The design strategy of bifunctional catalyst in this paper can be also applied to other fields.