Atomically Dispersed V-O2N3 Sites with Axial V-O Coordination on Multichannel Carbon Nanofibers Achieving Superior Electrocatalytic Oxygen Evolution in Acidic Media

The development of inexpensive, active, and robust nonprecious metal electrocatalysts toward the oxygen evolution reaction (OER) in acid media is highly imperative for renewable energy conversion techniques, yet greatly challenging. Inspired by the vanadium-containing oxygen-fixing enzymes in haloperoxidase in nature, herein, the atomically dispersed V sites anchored on N-doped multichannel carbon nanofibers (designated as V@NMCNFs hereafter) are rationally designed as high-efficiency electrocatalyst for the acidic OER. Substantial characterizations validate that the local coordination microenvironment of the V site is identified as an asymmetrical penta-coordinated V-O2N3 moiety with axial V-O coordination, which is further theoretically substantiated as an energetically favorable configuration with a reduced OER energy barrier by the density functional theory calculations. Consequently, the well-dispersed isolated V-O2N3 sites with exceptional intrinsic activity and unique nano-architecture furnish the well-designed V@NMCNFs with distinguished OER performance in a 0.5 m H2SO4 electrolyte, as reflected by the ultralow overpotential of 196 mV at 10 mA cm(-2) and remarkable long-term electrochemical durability, representing one of the most impressive nonprecious OER electrocatalysts to date. The synthetic methodology for SAC preparation and concept of electronic regulation proposed in this work offer perspectives to aid the design of other functional SAC systems with regulated coordination environments for efficient electrocatalysis.