Theoretical Studies On The Nitrogen Doped Graphene Confined Transition Metal Single Atom Catalyst

Single-atom catalyst is one of the frontier research fields in catalysis due to its high catalytic activity,selectivity and the maximum atom utilization.Using the nitrogen doped graphene to support the active transition metal(TM)single atom can form a stable TM-N-C catalyst.The active center of such catalyst is very sensitive to environment.Studying the effect of the microenvironmental structure of such confined catalyst on catalytic activity offer the predictive power for supported atomically dispersed catalyst design.Based on the first principle calculation of DFT,the effects of the concentration of active sites and the coordination environment of TM on the structural and electronic properties of nitrogen doped graphene confined single atom catalysts are studied in this work.The main results are summarized as follows:(1)The electronic properties of FeN4-graphene can be significantly affected by changing the concentration of FeN4,which can alter from semimetallicity to metallicity and to half-metallicity upon changing the concentration.(2)The half-metallic FeN4-graphene exhibits high catalytic performance in oxygen reduction reaction(ORR).The highly active partially-filled energy bands(PFED)in metallic channel can donate more electrons to the half-occupied orbital of O2 than other systems,giving rise to the high catalytic activity in ORR.(3)Changing the coordination environment of Mo can produce half-metallic to metallic behavior transition.