Pyridinic‑N Doped Porous Graphene Supported on Metal Substrates As the Promising Electrocatalyst for Oxygen Reduction Reaction

Nitrogen-doped carbon-based nanomaterials are promising electrocatalysts for oxygen reduction reaction (ORR) in energy conversion, but the doping type and site of nitrogen atoms are difficult to precisely control. Herein, we designed a novel porous graphene material containing only pyridinic N (PNG), exhibiting superior electrocatalytic ORR activity when it is supported on metal substrates. We have considered both Co (0001) and Ni (111) as the substrates to investigate the ORR process of PNG from density functional theory methods. Our researches have illustrated the optimal active site for ORR is the C atom next to the pyridinic N, locating at the hollow site with respect to the metal substrate. By introducing Co (0001) and Ni (111) substrates, the ORR electrocatalytic performance of PNG have been effectively enhanced with the lowest calculated overpotential of 0.41 V, which originated from the electronic coupling between the metal substrate and the C atoms of PNG. Finally, the ORR activity could be further enhanced under the tensile strain. Our study provided valuable guidance for the design of two-dimensional graphene-based heterojunction materials as efficient ORR electrocatalysts.