CeO₂‐Accelerated Surface Reconstruction of CoSe₂ Nanoneedle Forms Active CeO₂@CoOOH Interface to Boost Oxygen Evolution Reaction for Water Splitting

Abstract

Interface engineering is an efficient strategy to create high‐performance electrocatalysts for water splitting. In the present work, CeO₂@CoSe₂ nanoneedle on carbon cloth (CeO₂@CoSe₂/CC) demonstrates high efficiency for oxygen evolution reaction (OER) and water splitting. CeO₂ with abundant O vacancies facilitates the adsorption of OH⁻ and boosts the reconstruction of CoSe₂ into CoOOH at lower potentials. The in situ generated active CeO₂@CoOOH heterointerface upshifts the d‐band center of Co site, thereby decreasing the free energy of rate‐determining step (RDS) (^*O to ^*OOH) during the OER process. It delivers a low OER overpotential of 245 mV at 10 mA cm⁻². CeO₂@CoSe₂/CC is also found to be active for hydrogen evolution reaction (HER, 138 mV overpotential at 10 mA cm⁻²), profiting from CeO₂‐facilitated ^*H₂O dissociation and ^*H adsorption on CoSe₂. The overall water splitting is achieved over the CeO₂@CoSe₂/CC bifunctional electrode with a low electrolysis voltage of 1.54 V at 10 mA cm⁻². This work offers valuable insights into CeO₂‐assisted surface reconstruction as well as provides water electrolysis catalysts through interface engineering.