Precious-metal-free catalyst design strategies for stable anion-exchange membrane water electrolysis using seawater

Abstract

Anion-exchange membrane-based direct seawater electrolyzers are attractive solutions for large-scale hydrogen production, but their performance in seawater is hampered by side reactions and impurity-driven electrode degradation. Recent efforts have focused largely on the development of hydrogen and oxygen evolution catalysts in saline solutions, whereas the prevention of poisoning, scaling, and corrosion under seawater conditions remains unresolved. Here, we refocus catalyst design strategies for seawater electrolysis on durability and selectivity by mapping performance-decay pathways at both the cathode and anode and by categorizing catalyst architectures that sustain operation in complex electrolytes. This review places particular emphasis on precious-metal-free catalysts and their design strategies, including phase engineering and heteroatom doping to tune surface electronic structure and charge, and heterojunction designs that redistribute interfacial bands, suppressing unwanted reactions and providing sacrificial corrosion buffering. Additionally, benchmarking electrolysis performances in saline versus seawater discloses hidden sensitivities of impurity ions to both reactions, motivating future directions for catalyst design to achieve stable seawater electrolysis in anion-exchange membrane water electrolyzers (AEMWEs).