Tuning Binding Strength of Multiple Intermediates towards Efficient pH-universal Electrocatalytic Hydrogen Evolution by Mo8O26-NbNxOy Heterocatalysts.

Developing efficient and robust hydrogen evolution reaction (HER) catalysts for scalable and sustainable hydrogen production through electrochemical water splitting is strategic and challenging. Herein, heterogeneous Mo8O26-NbNxOy supported on N-doped graphene (defined as Mo8O26-NbNxOy/NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O-exposed Mo8O26 clusters covalently confined on NbNxOy nanodomains provide a distinctive interface configuration and appropriate electronic structure, where fully exposed multiple active sites give excellent HER performance beyond commercial Pt/C catalyst in pH-universal electrolytes. Theoretical studies reveal that the Mo8O26-NbNxOy interface with electronic reconstruction affords near-optimal hydrogen adsorption energy and enhanced initial H2O adsorption. Furthermore, the terminal O atoms in Mo8O26 clusters cooperate with Nb atoms to promote the initial H2O adsorption, and subsequently reduce the H2O dissociation energy, accelerating the entire HER kinetics.