Fe-Doped and Carbon Composite Multiphase Hetero-structured Catalysts Based on the Ion-Exchange Strategy for Seawater Electrolysis

Seawater electrolysis has attracted much attention as an environmentally friendly technology for hydrogen production. However, the presence of chloride ions, microorganisms, and other impurities in seawater hinders the development of seawater electrolysis, so it is crucial to construct catalysts with high catalytic activity and corrosion resistance. In this work, morphology modulation, Fe doping, and carbon composites were simultaneously achieved by the ion-exchange method and a subsequent selenization process. The prepared Fe-NiMoSe@C bifunctional catalyst with a hollow nanorod structure exhibited excellent catalytic activity and corrosion resistance in alkaline seawater, requiring only 362 and 354 mV to reach 500 mA cm–2 for HER and OER, while the electrolyzer assembled from it required only 1.83 V to drive 100 mA cm–2, with a Faraday efficiency close to 100% and stability up to 100 h. It was shown that the Fe doping optimizes the electronic environment and accelerates the reaction kinetics, the hollow nanorod structure exposes more active sites, and the carbon layer can resist corrosion by seawater, making Fe-NiMoSe@C an excellent bifunctional catalyst for seawater electrolysis.