Role of Hydrogen Spillover in Electrocatalytic Hydrogen Evolution from Water Splitting

The hydrogen spillover effect (HSPE) is an appealing interfacial phenomenon in the hydrogen evolution reaction (HER). However, the application of HSPE in transition metal-based electrocatalytic materials is still at an exploratory stage due to the unclear reaction mechanism and the complex electrolytic environment. How to apply the HSPE as a functionalized strategy for designing efficient electrocatalytic materials becomes the research focus. In order to better understand the role of HSPE in electrocatalytic water splitting, this chapter first introduces the basic principles of HSPE, followed by a review of electrocatalysts utilizing HSPE in acidic and alkaline electrolysis. The underlying mechanism of HSPE for improving the HER performance and the designing principles of HER catalysts are then analyzed. Lastly, the present issues in this research area and the promising research directions are proposed. Hopefully, this chapter can provide meaningful guidance for designing cost-effective and efficient HER electrocatalysts by applying the HSPE.