Unveiling the Role of Surface Self‐Reconstruction of Metal Chalcogenides on Electrocatalytic Oxygen Evolution Reaction

Transition metal chalcogenides are an important class of electrocatalysts with broad application prospects in alkaline oxygen evolution reactions. Many researchers are focusing on the in situ conversion of metal cations in catalysts, but have rarely considered the contribution of oxidation, leaching, and re‐absorption of chalcogenides to the catalytic activity. Herein, multiple characterization approaches are used to monitor the evolution mechanism and origin CoTe@CoS‐electrocatalyzed oxygen evolution reaction (OER) activity. The research results reveal that the electro‐oxidative dissolution of Te and S on the electrode surface forms TeO32− and SO32−, which are adsorbed on the electrode surface. Moreover, TeO32− and SO32− species will further transform into TeO42− and SO42−. As expected, the extra addition of mixed tellurite and sulfate ions to the Co (OH)2 electrolyte produces a synergistic effect that can significantly boost OER activity. Selenites reveal the analogous effect, indicating that the adsorption of chalcogenates the electrode surface has a universal effect on improving OER performance. The findings of this work provide unique insights into the species conversion of catalytic materials and the mechanism of enhancing catalytic activity during OER processes. Transition metal chalcogenides (TMCs) are efficient oxygen evolution reaction (OER) electrocatalysts. Herein, CoTe@CoS is used as the research model to investigate how the electrode electrocatalyzes OER behavior and what active species are generated during the electrocatalysis process. The results show that the electrooxidation, leaching, and re‐absorption of chalcogenate anions in TMCs contribute significantly to the enhancement of OER activity.