Corrosion-resistant single-atom catalysts for direct seawater electrolysis

Direct seawater electrolysis (DSE) for hydrogen production is an appealing method for renewable energy storage. However, DSE faces challenges such as slow reaction kinetics, impurities, the competing chlorine evolution reaction at the anode, and membrane fouling, making it more complex than freshwater electrolysis. Therefore, developing catalysts with excellent stability under corrosion and fulfilling activity is vital to the advancement of DSE. Single-atom catalysts (SACs) with excellent tunability, high selectivity and high active sites demonstrate considerable potential for use in the electrolysis of seawater. In this review, we present the anodic and cathodic reaction mechanisms that occur during seawater cracking. Subsequently, to meet the challenges of DSE, rational strategies for modulating SACs are explored, including axial ligand engineering, carrier effects and protective layer coverage. Then, the application of in-situ characterization techniques and theoretical calculations to SACs is discussed with the aim of elucidating the intrinsic factors responsible for their efficient electrocatalysis. Finally, the process of scaling up monoatomic catalysts for the electrolysis of seawater is described, and some prospective insights are provided.