Oxygen Reduction Reaction in Seawater as Electrolyte: From Mechanism and Electrocatalyst Design to System Integration

ABSTRACT The oxygen reduction reaction (ORR) in seawater as the electrolyte combines resource accessibility with significant application potential, providing important opportunities for chemical production and the development of electrochemical energy technologies. However, the multi‐ion synergistic failures induced by Cl − , Mg 2+ , Ca 2+ , and other species in seawater severely restrict catalyst performance. Based on this, this review summarizes the latest research advances in ORR in seawater and simulated seawater systems. Starting from the reaction mechanisms, the 2e − and 4e − reaction pathways and the inhibitory effects of key ions on ORR are elucidated. Subsequently, electrocatalyst design strategies for enhancing activity, regulating selectivity, and improving stability are summarized, followed by an overview of the integration and application advances of ORR in seawater for H 2 O 2 electrosynthesis and energy devices. Finally, the engineering challenges and techno‐economic issues facing seawater‐based ORR systems are analyzed, and future development directions involving multidimensional synergistic advancements are proposed. This review aims to provide theoretical insights and engineering guidance for the design of high‐performance electrocatalysts for ORR in seawater and the construction of practical application systems.