Atomically dispersed V-N-C catalyst with saturated coordination effect for boosting electrochemical oxygen reduction

• V-N-C SAC was designed for electrocatalytic ORR using biomimetic strategy. • Abnormal saturated coordination effect boosts ORR activity of V-N-C SAC. • V-N-C SAC shows innate Fenton nonreactivity to improve ORR stability. Single atom catalysts (SACs) exhibit impressive catalytic activity for various reactions due to low coordination environment and tunable electronic structures, attracting increasing attention. However, it is big challenge to develop transition-metal-based SACs for oxygen reduction reaction (ORR) with high stability. Bioinspired by the structure and mechanism of vanadium-dependent haloperoxidase, we herein demonstrate that saturated coordination could boost ORR activity of atomically dispersed V-N-C catalyst combining DFT prediction and experimental verification. Spontaneous axial OH coordination to V-N-C catalyst in alkaline electrolyte not only optimizes the adsorption interaction for key intermediates to boost ORR activity, but also keeps vanadium atom at the highest valence against Fenton activity to improve the stability. The as-designed catalyst exhibits half-wave potential of 0.858 V vs . RHE for ORR, comparable to the commercial Pt/C benchmark. This work provides a proof-of-concept design of SACs and broadens the horizon of its potential applications.