Modifying the Redox Properties of Co₃O₄ for Enhanced Acidic Oxygen Evolution by Lattice Stretching

Proton exchange membrane water electrolysis technology demonstrates significant potential for advancing the green hydrogen economy, yet it remains constrained by the reliance on noble metal catalysts. This study develops a low-cost Co₃O₄ catalyst via a potassium bromide-assisted thermal decomposition method, which induces lattice tensile strain to modulate the redox properties of cobalt, leading to a remarkable enhancement of the oxygen evolution reaction (OER) performance of Co₃O₄ in acidic media. The prepared Co₃O₄ electrocatalyst exhibits outstanding OER performance under acidic conditions, requiring only 377 mV of overpotential to achieve a current density of 10 mA·cm^-2 and maintaining stable operation for 150 h. In situ differential electrochemical mass spectrometry (DEMS) analysis and cyclic voltammetry results confirm that the lattice tensile strain alters the redox mechanism of Co₃O₄, promoting its transition toward the oxide pathway mechanism and thereby improving both the activity and stability of the oxygen evolution reaction.