Novel amorphous NiCuS H2-evolution cocatalyst: Optimizing surface hydrogen desorption for efficient photocatalytic activity

Cost-effective nickel sulfide has attracted great interest as a favorable cocatalyst for achieving highly-efficient photocatalytic activity, but its H2-evolution performance is still suppressed owing to the strong sulfur-hydrogen bonds (S-Hads). In this study, the interfacial S-Hads bonds can be effectively weakened by the formation of the electron-rich active S sites via introducing Cu atoms into the amorphous NiSx cocatalyst. By use of a precursor-complexation photodeposition strategy, novel amorphous NiCuSx H2-evolution cocatalyst (a-NiCuSx) have been constructed and simultaneously anchored onto TiO2 to form a-NiCuSx/TiO2 photocatalysts. Photocatalytic results reveal that the optimized a-NiCuSx/TiO2 (3:1) photocatalyst (427.9 μmol h−1, AQE = 34.67%) achieves an enhanced H2-generation activity compared to the a-NiSx/TiO2 (226.1 μmol h−1). As investigated by density-functional-theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS), the Cu heteroatom into a-NiSx can induce its charge redistribution to form electron-rich active S sites, thereby effectively weakening the S-Hads bonds to optimize hydrogen adsorption and accordingly boosting the photocatalytic H2-generation rate. This work offers a promising and rational method to optimize the catalytic centers of a H2-evolution cocatalyst, presenting great potential in designing highly-efficient photocatalyst for future scalable and sustainable H2 production.