In Situ Formation ZnIn2 S4 /Mo2 TiC2 Schottky Junction for Accelerating Photocatalytic Hydrogen Evolution Kinetics: Manipulation of Local Coordination and Electronic Structure.

Abstract

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.