▎ 摘　　要

A post-treatment approach is presented to prepare nitrogen-doped single-layer graphene via ultraviolet/ozone (UV/O-3) irradiation followed by NH3 annealing. Under optimal experimental conditions, a maximum atomic ratio (N/C) of 16.6% can be reached. X-ray photoelectron spectroscopy analysis reveals that only one type of pyridinic N is doped in the graphene lattice, which can be used as an ideal platform to investigate its catalytic activity toward oxygen reduction reaction (ORR). Electrochemical results demonstrate that ORR on the pyridinic N doped graphene sheet occurs via a two-electron transfer process, indicating that the pure pyridinic N doped graphene is not an effective 4e-process promoter.