Electrodeposition-fabricated catalysts for polymer electrolyte water electrolysis

Water electrolysis using renewable energy sources such as solar and wind power has the advantage of producing hydrogen with high efficiency and zero emissions. Solid polymer electrolyte water electrolysis (SPEWE) is divided into anion exchange membrane electrolysis (AEMWE) carried out in an alkaline environment and proton exchange membrane electrolysis (PEMWE) carried out in an acidic environment. Research on the electrocatalysts used in these electrolysis procedures has focused on the development of transition metal-based catalysts with catalytic activity, high stability, and low cost that can replace the currently used noble-metal based electrocatalysts. Among the various electrocatalyst fabrication methods, electrodeposition can be used to fabricate catalysts in a simple manner at low cost and high purity. In addition, catalysts can be directly electrodeposited onto a substrate such as a gas diffusion layer, simplifying the electrode fabrication process and readily enabling the advantageous control of the physical, chemical, structural, and compositional properties of the catalyst. In this paper, we summarize the characteristics and structures of the water electrolysis catalysts prepared by the electrodeposition method based on recent research studies that suggest their applicability to practical water electrolysis systems in the future.