Precious metal free catalyst designs for stable anion exchange membrane water electrolysis using seawater

Abstract

Anion-exchange membrane based direct seawater electrolysers are one of the attractive solutions for large-scale hydrogen production, but operation in seawater is hampered their performances by side reactions and impurity-driven electrode degradation. Recent efforts have largely focused on the development of hydrogen and oxygen evolution catalysts in saline solutions, whereas preventing 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 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, leading managing intermediates and providing sacrificial corrosion buffering. Additionally, benchmarking electrolysis performances in saline versus seawater discloses hidden sensitivities of impurity ions to both reactions, motivating future catalysts design directions for achieving stable seawater electrolysis in AEMWE.