Tuning binding strength of multiple intermediates towards efficient pH-universal electrocatalytic hydrogen evolution by Mo${}_8$O${}_{26}$-NbN${}_x$O${}_y$ 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 Mo${}_8$O${}_{26}$-NbN${}_x$O${}_y$ supported on N-doped graphene (defined as Mo${}_8$O${}_{26}$-NbN${}_x$O${}_y$/NG) is synthesized by controllable hydrothermal reaction and nitridation process. The O-exposed Mo${}_8$O${}_{26}$ clusters covalently confined on NbN${}_x$O${}_y$ 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 Mo${}_8$O${}_{26}$-NbN${}_x$O${}_y$ interface with electronic reconstruction affords near-optimal hydrogen adsorption energy and enhanced initial H${}_2$O adsorption. Furthermore, the terminal O atoms in Mo${}_8$O${}_{26}$ clusters cooperate with Nb atoms to promote the initial H${}_2$O adsorption, and subsequently reduce the H${}_2$O dissociation energy, accelerating the entire HER kinetics. (© 2023 Wiley‐VCH GmbH)