▎ 摘　　要

The development of non-precious metal-based electrocatalysts has attracted much research attention because of their high oxygen reduction reaction (ORR) activities, low cost, and good durability. By one-step in-situ ball milling of graphite, pyrrole, and cobalt salt without resorting to high-temperature annealing, we developed a general and facile strategy to synthesize bio-inspired cobalt oxide and polypyrrole coupled with a graphene nanosheet (Co3O4-PPy/GN) complex. Herein, the exfoliation of graphite and polymerization of pyrrole occurred simultaneously during the ball milling process. Meanwhile, the Co3O4 and Co-N (x) ORR active sites were generated from the oxidized cobalt ion, cobalt-PPy, and the newly exfoliated graphene nanosheets via strong pi-pi stacking interactions. The resultant Co3O4-PPy/GN catalysts showed efficient electrocatalytic performances for ORRs in an alkaline medium with a positive onset and reduction potentials of-0.102 and-0.196 V (vs. Ag/AgCl), as well as a high diffusion-limited current density (4.471 mA center dot cm(-2)), which was comparable to that of a Pt/C catalyst (4.941 mA center dot cm(-2)). Compared to Pt/C, Co3O4-PPy/GN catalysts displayed better long-term stability, methanol tolerance, and anti-CO-poisoning effects, which are of great significance for the design and development of advanced non-precious metal electrocatalysts.