In Situ Formation ZnIn₂ S₄ /Mo₂ TiC₂ 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 ZnIn₂ S₄ /Mo₂ TiC₂ Schottky junctions are designed to be constructed through the interfacial local coordination of In³⁺ with the electronegative O terminal group on Mo₂ TiC₂ 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 ZnIn₂ S₄ to Mo₂ TiC₂ is established by the formed local nucleophilic/electrophilic region. The increased local electron density of Mo₂ TiC₂ inhibits the backflow of electrons, boosts the charge transfer and separation, and optimizes the hydrogen adsorption energy. Therefore, the ZnIn₂ S₄ /Mo₂ TiC₂ 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 ZnIn₂ S₄ . This work provides some insights and inspiration for preparing MXene-based Schottky catalysts to accelerate PHE kinetics.