In Situ Formation ZnIn 2 S 4 /Mo 2 TiC 2 Schottky Junction for Accelerating Photocatalytic Hydrogen Evolution Kinetics: Manipulation of Local Coordination and Electronic Structure.

Regulating electronic structures of the active site by manipulating the local coordination is one of the advantageous means to improve photocatalytic hydrogen evolution (PHE) kinetics. Herein, the ZnIn 2 S 4 /Mo 2 TiC 2 Schottky junctions are designed to be constructed through the interfacial local coordination of In 3+ with the electronegative O terminal group on Mo 2 TiC 2 based on the different work functions. Kelvin probe force microscopy and charge density difference reveal that an electronic unidirectional transport channel across the Schottky interface from ZnIn 2 S 4 to Mo 2 TiC 2 is established by the formed local nucleophilic/electrophilic region. The increased local electron density of Mo 2 TiC 2 inhibits the backflow of electrons, boosts the charge transfer and separation, and optimizes the hydrogen adsorption energy. Therefore, the ZnIn 2 S 4 /Mo 2 TiC 2 photocatalyst exhibits a superior PHE rate of 3.12 mmol g -1 h -1 under visible light, reaching 3.03 times that of the pristine ZnIn 2 S 4 . This work provides some insights and inspiration for preparing MXene-based Schottky catalysts to accelerate PHE kinetics.