Unveiling the structure evolution and regulation of dynamic activity and stability of Co3Se4 electrocatalysts under alkaline hydrogen evolution reaction with SeO32− ions

Transition metal selenides possess unique electronic properties and functional tunability, making them promising electrocatalysts for various applications. However, the structure evolution of cobalt selenide and its effect on catalytic activity and stability under alkaline hydrogen evolution reaction (HER) have not been fully understood. Herein, this study investigates the structure evolution, catalytic activity, and stability of Co3Se4 electrodes under alkaline HER. Continuous Se leaching transforms Co3Se4 into Co(OH)2 during HER, leading to an activation process in the early stage and a decay process in the later stage. Adding SeO32− ions in the electrolyte effectively inhibits Se leaching and excessive hydroxylation, enhancing stability. Mechanistic studies show that SeO32− added to the electrolyte can increase the concentration of SeO32− ions in the electric double layer to regulate the dynamic balance of Se leaching. This work provides insight into structure evolution, dynamic activity regulation, and stability of electrode materials during electrochemical reduction processes.