▎ 摘　　要

The development of efficient metal-free electrocatalysts for oxygen electrocatalysis is of great significance for various energy conversion devices. Herein, novel nitrogen-doped holey graphene nanocapsules (NHGNs) are reported prepared by self-assembly of graphene oxide nanosheets on the surface of amino-functionalized silica template and NH3 activation with simultaneously enhanced nitrogen doping and etching of nanopores in graphene, followed by template etching. The silica template is demonstrated to show a substrate-enhanced effect on nitrogen doping and etching of nanopores in graphene based on density functional theory calculations. Benefiting from the large surface area, unique pore distribution, and high surface functionality of nitrogen doping, the resulting NHGNs exhibit superior bifunctional electrocatalytic activity and durability for both oxygen reduction reaction and oxygen evolution reaction, which is similar to that of the commercial Pt/C and RuO2 electrocatalysts, respectively. This work presents an advance in developing new nitrogen-doped graphene species for highly efficient metal-free electrocatalysis.