▎ 摘　　要

Graphene and other two-dimensional materials have been used as catalysts in the oxygen reduction reaction (ORR) in fuel cells with a few limitations in terms of the onset potential and number of electrons transferred per oxygen molecule. We find that heavily nitrogenated graphene with a nitrogen content of 14-18 wt.% and a high proportion of pyrrolic nitrogen, prepared under microwave irradiation, shows excellent activity towards ORR, comparable to platinum, with the transferred electron number of 4.