Modulation of Co Ions in Mesoporous Co 3 O 4 by Decorating Ultrafine Pt Particles for Boosted Oxygen Evolution Reaction

ABSTRACT Developing efficient and durable electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing large‐scale water electrolysis and renewable energy conversion. Spinel Co 3 O 4 has attracted increasing attention due to its low cost, structural robustness, and tunable electronic configuration. However, its catalytic performance is limited by sluggish reaction kinetics and insufficient availability of active Co sites. In this work, we systematically investigate the effects of Pt incorporation on the electronic structure, surface chemistry, and OER activity of Co 3 O 4 . Comparative analyses reveal that samples containing smaller Pt nanoparticles exhibit a higher concentration of Co 2+ species and enhanced Pt─O─Co interfacial coupling. This modulation significantly accelerates the adsorption and deprotonation of OH, promotes the pre‐oxidation of Co center, and ultimately lowers the overpotential. Benefiting from these synergistic effects, Pt/Co 3 O 4 ‐24 delivers superior OER performance with improved kinetics and stability. This study provides new insights into the structure–activity relationships governing OER in Pt‐modulated spinel oxides and offers a rational strategy for designing high‐efficiency metal–oxide electrocatalysts.