An In-Depth Theoretical Exploration of Influences of Non-Metal-Elements Doping on the ORR Performance of Co-gN(4)

摘要

Single atom catalysts (SACs) show a great attraction towards the oxygen reduction reaction (ORR) owing to its advantage in overcoming the cost issue of fuel cell because of its high utilization, low cost and great CO tolerance. However, theoretical investigation on the influences of different doping on the ORR catalytic activity of Co SACs has not been systematically performed. In this regard, the influences of non-metal-elements doping (B, N, Si, P, S) on the ORR catalytic activity of Co-gN(4) is well explored based on density functional theory (DFT). The rate-limiting step for the ORR on Co-gN(4) is the formation of OOH. When the doping content of B increases, the adsorption on Co site becomes weaker which limits the occurrence of 4e(-) ORR process. N doping shows a weak promotion on the ORR process on Co site. The Si site next to N can be poisoned by OH. The P site next to N will be poisoned by O at high potential and OH at low potential. The S site next on N would be poisoned by O. It is revealed that the ORR process on Co site can be promoted when the carbon next to N is replaced by Si/P/S by promoting the rate-limiting step.