The future of alkaline water splitting from the perspective of electrocatalysts-seizing today's opportunities

Abstract

Water electrolysis currently accounts for approximately 4% of the global hydrogen production volume, indicating there is a significant room to provide more low-carbon hydrogen with this technology. At present, alkaline electrolysis of water emerges as the most promising technology to realize large-scale green hydrogen production. Electrocatalysts that can operate efficiently and stably at high current density have become a major constraint in moving towards industrialization. In this review, we summarize and discuss the mechanisms and low-cost catalysts reported so far for the electrolytic water reaction under alkaline conditions. Subsequently, based on the requirements and theoretical guidance for its application at high current densities, we further introduce strategies to enhance the performance and stability of electrocatalysts. Finally, we undertake an outlook on the prospective challenges and opportunities beyond the electrolytic hydrogen generation technology. It concludes that the deployment and economization of hydrogen energy technologies must be accelerated at this stage in order to facilitate their widespread penetration and use in a wide range of industries.