Construction of bis-transition metal sulfide Schottky junctions for enhanced photocatalytic H2 evolution performance

One efficient way to increase the activity of photocatalytic hydrogen generation is to construct Schottky junctions. This work presents the successful synthesis of hollow spherical CuNi 2 S 4 nanoparticles with quasi-metallic characteristics using an approach of chemical deposition and hydrothermal synthesis. The hollow structure significantly improved light capture, and these nanoparticles were subsequently loaded as hydrogen evolution sites onto MnCdS, forming the MnCdS/CuNi 2 S 4 Schottky junction. Photocatalytic hydrogen evolution (PHE) activity is significantly improved by the efficient spatial separation of photogenerated charge carriers made possible by the establishment of Schottky junctions. Combining in-situ X-ray Photoelectron Spectroscopy (XPS) analysis and Density Functional Theory (DFT) computations, the formation mechanism of Schottky junctions and the PHE process were investigated. The establishment of the Schottky barrier successfully inhibited the reverse flow of photogenerated electrons, which facilitated charge carrier separation and consequently boosted photocatalytic efficiency. This work demonstrates a promising method for fabricating Schottky junction photocatalysts based on transition metal sulfides. • Use of abundant and relatively inexpensive transition metal sulfides as photocatalysts. • CuNi 2 S 4 with hollow sphere morphology was synthesized to enhance the light trapping capability. • MnCdS/CuNi 2 S 4 Schottky junction photocatalysts have been prepared with metalloid CuNi 2 S 4 loaded on MnCdS. CuNi 2 S 4 loading effectively improves charge transfer and transport rates and promotes spatial separation of photogenerated electron-hole pairs. • In-situ XPS and work function calculations analyze and demonstrate the formation of Schottky junctions and explain the mechanism of their formation.