High‐Voltage‐Enabled Stable Cobalt Species Deposition on MnO2 for Water Oxidation in Acid

at the voltage >1.8 V versus reversible hydrogen electrode (RHE). However, when the potential is <1.8 V, the corresponding other cobalt species is too unstable to facilitate the OER. Density functional theorycalculations reveal that the deposited cobalt oxides can act as active sites, thus effectively reducing the reaction energy barrier of the rate-determining step. This work provides a new perspective for enhancing the stability of cobalt-based electrocatalyst. In the future, the dual consideration of applied potential and stable species of active element in the Pourbaix diagram may be a new direction for developing acid-stable electrocatalysts.