Mechanism and research progress of hydrogen spillover in hydrogen evolution reaction

Hydrogen production technology by electrolyzing water plays an increasingly important role in the production of renewable hydrogen energy and is a powerful means to effectively alleviate the dependence on fossil fuels. It is an urgent task to develop electrocatalysts with high activity, high stability and low cost. Cathodic hydrogen evolution reaction (HER) of water electrolysis has attracted much attention due to its unique reaction mechanism. In recent years, the developed hydrogen spillover binary catalyst has been widely concerned and studied because of its advantages of achieving efficient hydrogen transfer, which has opened up a new way to promote the development of hydrogen production from electrolytic water. This paper comprehensively summarizes the latest research progress of hydrogen spillover binary electrocatalysts for HER. Firstly, the mechanism of HER is introduced. Then, the mechanism of hydrogen spillover and its role in HER are discussed. More importantly, the latest regulation methods to improve HER performance through hydrogen spillover effect and main experiments to prove the existence of hydrogen spillover are emphatically introduced. Finally, we systematically discuss some problems and challenges faced by hydrogen spillover electrocatalysts in the current development and look forward to their future application prospects.