An overview of design strategies and recent advancements in complex 3d transition metal-based electrocatalysts for alkaline oxygen evolution reaction

Abstract Oxygen evolution reaction (OER) is a critical half-reaction in numerous electrochemical processes, such as water electrolysis, CO 2 reduction, and metal-air batteries, yet its sluggish kinetics significantly limit overall efficiency, requiring advanced catalysts. Earth-abundant transition metal-based multi-metal catalysts have emerged as promising alternatives to precious metal-based systems, offering tunable properties and enhanced catalytic performance, particularly in alkaline environments. Given the promising potential of these catalysts, an in-depth understanding of the relationship between their catalytic properties and activity is essential for enabling rational catalyst design. This review outlines fundamental OER mechanisms, followed by a discussion of design principles for multi-metal catalysts, focusing on activity descriptors and dynamic surface reconstruction. Recent advancements in multi-metal catalysts are evaluated, highlighting innovative strategies and breakthroughs. Lastly, the review addresses remaining challenges and future directions, emphasizing the need for deeper insights into synergistic interactions among catalyst components and the development of catalysts to meet practical-scale performance demands.