Manipulating electron redistribution induced by asymmetric coordination for electrocatalytic water oxidation at a high current density.

Electronic structure manipulation with regard to active site coordination is an effective strategy to improve the electrocatalytic oxygen evolution reaction (OER) activity. Herein, we present the structure-activity relationship between oxygen-atom-mediated electron rearrangement and active site coordination asymmetry. Ni ions are introduced to FeWO on Ni foam (NF) via self-substitution to break the symmetry of the FeO octahedron and regulate d-electron structure of Fe sites. Structural regulation optimizes the adsorption energy of hydroxyl on the Fe sites and promotes the partial formation of hydroxyl oxide with high OER activity on the tungstate surface. FeNiWO/NF with the asymmetric FeO octahedron of Fe sites can achieve an ultralow overpotential of 170 mV at 10 mA cm and 240 mV at 1000 mA cm with robust stability for 500 h at high current density under alkaline conditions. This research develops novel electrocatalysts with impressive OER performance and provides new insights into the design of highly active catalytic systems.