Lowering Schottky barrier in MoC-based cocatalyst via heteroatoms tunning for enhanced photocatalytic hydrogen evolution

Abstract

The simultaneous construction of efficient hydrogen evolution surfaces and the establishment of effective electron transport channels are crucial for improving the efficiency of photocatalytic hydrogen evolution reactions (PHERs). Molybdenum carbide materials are considered strong substitutes for Pt co-catalysts in PHERs because their electronic structure is similar to that of Pt. However, it is still challenging to enhance the kinetics of molybdenum carbide for hydrogen evolution reactions (HERs) while improving interface electron transport properties. In this study, low electronegativity heteroatoms P were introduced into metalloid MoC to adjust the overpotential of HERs while tuning the Schottky barrier between MoC and Zn0.5Cd0.5S. Due to the excellent charge separation efficiency in photocatalysts driven by the atomic-scale tuning of interfacial energetics on the prerequisite of not impairing the kinetics for surface reactions, the optimal P-MoC-modified Zn0.5Cd0.5S displayed a hydrogen evolution rate of 28.98 mmol·g−1·h−1, which was 11.59 and 1.51 times higher than that of pure Zn0.5Cd0.5S and Pt-modified Zn0.5Cd0.5S, respectively. This study provides a reference for the design of a high-efficiency co-catalyst and provides a new way for the regulation of the Mott–Schottky barrier.