Modulating the reaction pathway of tricobalt tetraoxide-based catalysts for advanced oxygen evolution

Oxygen evolution reaction (OER) is a critical process in renewable energy technologies. However, its large-scale application faces two major challenges: slow reaction kinetics and heavy reliance on noble metal catalysts. Tricobalt tetraoxide (Co₃O₄) is an affordable transition metal oxide with a favorable electronic structure, emerges as a promising alternative to noble metals. However, its performance is constrained by linear scaling relationship (LSR). LSR refer to the linear correlations between the adsorption free energies of intermediates, which prevent the simultaneous optimization of all steps, thereby limiting the maximum catalytic performance. Due to these scaling relationships, Co₃O₄-based catalysts following the conventional adsorbate evolution mechanism (AEM) inevitably require a high overpotential. To overcome this limitation, researchers have developed various strategies to modulate OER pathway. These methods not only optimized AEM but also promote a shift toward other mechanisms, such as lattice oxygen mechanism (LOM) or oxide path mechanism (OPM). This review systematically classifies different strategies for modifying Co₃O₄-based catalysts. It focuses on these strategies can not only improve but also completely change the OER reaction pathway, thus providing a clear design guide to overcome the scaling relationship and direct future development.