Scalable and straightforward synthesis of electrocatalysts for green hydrogen economy via high-current-density alkaline water splitting

Water electrolysis for high-purity hydrogen production under alkaline conditions is essential for achieving hydrogen energy economy. Developing straightforward synthetic strategies for fabricating high-performance scalable electrocatalysts is pivotal for efficiency enhancement in water electrolysis at industrially relevant current densities (≥500 mA cm^-2) and enabling cost-effective continuous electrocatalyst production. Herein, we summarize the recent advancements in scalable electrocatalyst construction for high-current-density water electrolysis. First, brief descriptions of various straightforward synthetic approaches are introduced, including hydrothermal and solvothermal synthesis, electrodeposition, corrosion engineering, Joule-heating and combustion, owing to their advantages of operational simplicity, effective modification, universality and scalability. Next, the recent advancements in developing scalable electrocatalysts using these approaches for high-current-density water electrolysis are overviewed and discussed. Lastly, current key challenges and potential future directions of these straightforward synthetic approaches are proposed. This review aims to offer new insights into designing and synthesizing innovative scalable electrocatalysts for industrial-scale hydrogen production.