Application of Hydrogen Spillover to Enhance Alkaline Hydrogen Evolution Reaction

Abstract Alkaline water splitting has shown great potential for industrial‐scale hydrogen production. However, its broad application is constrained by hydrogen evolution reaction (HER) electrocatalysts, which struggle to achieve optimal current density at low overpotential. The utilization of the hydrogen spillover effect to augment the performance of HER represents a burgeoning area of research. Although previous studies mainly focused on hydrogen spillover in acidic media, the latest studies have shown that hydrogen spillover also exists under alkaline conditions, and its role in improving HER performance cannot be ignored. This review examines the mechanisms of HER under acidic and alkaline conditions, elucidating the distinctive behavior of hydrogen spillover in these environments and its influence on catalytic processes. At the same time hydrogen spillover characterization methods are systematically summarized, these technologies for understanding and control of hydrogen release process provides strong support. Finally, the recent electrocatalysts that enhance the catalytic performance of alkaline HER by hydrogen spillover effect are comprehensively sorted out and summarized. This review not only demonstrate the practical value of hydrogen spillover under alkaline conditions, but also provide new directions for future design and optimization of electrocatalysts.