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Cobalt Oxide-based Catalysts for Acidic Oxygen Evolution Reactions

Huihui Li , Shuhao Wang , Chuan Zhao

Abstract

Proton exchange membrane water electrolysis (PEMWE) is a cornerstone technology for green hydrogen production, yet the sluggish oxygen evolution reaction (OER) in acidic media remains a major bottleneck. Noble metal oxides such as IrO 2 and RuO 2 are effective but suffer from high cost and scarcity. As a non-precious alternative, spinel cobalt oxide (Co 3 O 4 ) has attracted attention due to its promising performance results from its mixed-valence structure, tunable electronic properties, and catalytic potential. However, its practical application is challenged by poor conductivity, moderate activity, and instability under acidic conditions due to proton attack and lattice degradation. This review summarizes recent advances in Co 3 O 4 -based electrocatalysts for acidic OER. We first introduce three key OER pathways: adsorbate evolution mechanism (AEM), lattice oxygen mechanism (LOM), and oxide path mechanism (OPM), and their relevance to Co 3 O 4 performance.Then, we introduce the structural and electronic characteristics of Co 3 O 4 that influence its catalytic behavior. Next, we review a range of engineering strategies, including element doping, heterostructure construction, surface modification and defect engineering, all aimed at enhancing activity and durability. Finally, we highlight critical challenges and offer perspectives for advancing Co 3 O 4 as a viable acidic OER catalyst.

CH25104  Accepted 20 August 2025

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