Valence gradient induced charge transfer enabling efficient hydrogen spillover in hydrogen evolution

The realization of the hydrogen spillover effect in metal-supported catalysts is an effective strategy for enhancing the performance of hydrogen evolution reactions (HERs). However, regulating the interaction between the substrate and the metal to promote the spillover process remains challenging. In this study, we construct a Pt nanoparticle catalyst supported by molybdenum oxide rich in oxygen vacancies (Pt-NP/MoOx). Enhanced hydrogen transfer is achieved by regulating the microenvironment of the substrate surface. Specific experiments and theoretical analyses demonstrate that the reduction treatment of the substrate induces the formation of oxygen vacancies, valence gradients, and amorphous-crystalline interfaces, resulting in strong interactions and electron transfer to Pt nanoparticles, thus ensuring efficient hydrogen spillover at the interface. Consequently, PtNP/MoOx exhibits excellent HER activity of-24 mV at 10 mA cm- 2 . This study offers a proof-of-concept for comprehending the influence of the substrate surface environment on the performance of noble metal-based catalysts.