Bioinspired One-Step Pyrolysis Fabrication of 3D Porous Co, N, P-doped Carbon Nanosheets with Enriched CoN_x Active Sites as High-Performance Bifunctional Oxygen Electrocatalyst for Rechargeable Zn–Air Battery

Herein, a one-step pyrolysis strategy was developed to prepare Co, N, P-doped porous carbon nanosheets (Co, N, P-PCNS) with abundant CoNx active sites, using vitamin B12 (VB12) as the Co and P source and g-C3N4 as the N and C resource. The Co, N, P-PCNS exhibited prominent oxygen reduction performance with a positive half-wave potential (E1/2 = 0.87 V) alternative to commercial Pt/C (E1/2 = 0.84 V) in 0.1 M KOH electrolyte, coupled with a low overpotential (η = 319 mV) for oxygen evolution at 10 mA cm–2 in alkaline circumstance (i.e., 1.0 M KOH). Impressively, the as-assembled Zn–air battery attained remarkable peak power density of 101.3 mW cm–2 at a potential of 0.71 V. This work offers impetus for rational fabrication of cost-effectiveness and high-activity oxygen catalysts for energy transportation and storage.