Application of Hydrogen Spillover in Alkaline Hydrogen Evolution Reaction

Alkaline water splitting has shown great potential for industrial‐scale hydrogen production. However, its wide application is still limited by the performance of hydrogen evolution reaction (HER) electrocatalysts, which are difficult to achieve ideal current density under low overpotential. Applying the hydrogen spillover effect to enhance HER performance has become an emerging research direction. Although previous studies mainly focused on hydrogen overflow in acidic media, the latest studies have shown that hydrogen overflow also exists under alkaline conditions, and its role in improving HER performance cannot be ignored. In this paper, the characteristic differences of the hydrogen overflow effect under acidic and alkaline conditions were investigated in depth, and the unique behavior of hydrogen overflow in the two different environments and its influence on the catalytic process were analyzed. System hydrogen spillover characterization methods are summarized at the same time, these technologies for understanding and control of hydrogen relief 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. These findings not only demonstrate the practical value of hydrogen spillover under alkaline conditions, but also provide new directions for future design and optimization of electrocatalysts.