Regulating interfacial water for oxygen transfer to benzylic C(sp<sup>3</sup>)-H bonds via Ni-activated tungsten-oxygen covalency.

Abstract

Recent studies on the electrocatalytic oxygen transfer from water to organic compounds have gained significant attention due to their sustainability and selectivity. However, the direct coactivation of inert hydrocarbons and water typically requires high oxidation potentials, leading to oxygen evolution reactions and low Faradaic efficiencies. Herein, a Ni-activated tungsten-oxygen covalency anode is designed for the efficient oxygen transfer from water to benzylic C(sp³)-H bonds via a Ni-regulated interfacial water structure between the anode and electrolyte. Both experimental and theoretical results reveal the critical role of W-O covalency sites with Ni-heteroatoms for boosting efficient oxygen transfer via breaking the dense interfacial hydrogen bond network and inhibiting the undesired oxygen evolution reactions, facilitating the coactivation of oxygen species and C(sp³)-H bonds. Thus, a Faradaic efficiency of > 56% in a water-involved system has been achieved. This work provides important insight into designing electrocatalytic systems for inert C-H oxidation.