Structurally distorted wolframite-type CoxFe1-xWO4 solid solution for enhanced oxygen evolution reaction

The activity of electrocatalyst is dominant by the spin configuration of active sites, which is strongly related to its local structure. Herein, for the first time, the intrinsic relationships among local structural distortion, spin configuration and oxygen evolution reaction (OER) activity of the sample are systematically studied by taking the solid solution of transition metal tungstates (CoxFe1-xWO4) with tunable degrees of local structural distortions as a platform, and proposed that the local structural distortion induced spin transition is account for its high catalytic activity. Benefiting from the co-presence of high spin and low spin states, the Co0.708Fe0.292WO4 exhibits the best OER activity among all samples with a small overpotential of 327 mV for 10 mA cm(-2) and a large current density of 254 mA cm(-2) at 1.825 V (vs RHE) in 1 M KOH solution. This work introduces a deeply understanding on the role of local structural distortion played in OER process.