Plasmonic Cu–Ni bimetal nanoparticles coupled with ultrathin CdS nanosheets for remarkably improved photocatalytic H2 generation under visible-light irradiation

Abstract

The utilization of the surface plasmon resonance (SPR) effect and metal cocatalyst decoration to form a Schottky junction are two effective methods to promote photocatalytic performances. However, combining these two approaches in a single photocatalyst system is challenging. Here, a simple solution-phase strategy is employed to integrate plasmonic Cu–Ni bimetal nanoparticles into ultrathin CdS nanosheets to enhance photocatalytic activity. The optimized Cu–Ni/CdS ternary photocatalyst exhibits a photocatalytic H₂ evolution rate of 28.19 mmol g⁻¹ h⁻¹, which is more than 88 times higher than that of CdS and also significantly enhanced compared to that of Cu/CdS and Ni/CdS binary photocatalysts. Furthermore, 8% Cu–Ni/CdS demonstrates a high apparent quantum yield (AQY) of 21.5% at 400 nm and 12.1% at 520 nm, respectively. The as-obtained nanocomposites showcase exceptional stability during cycling measurements. The impressive photocatalytic activity of Cu–Ni/CdS can be credited to the synergistic effect of the SPR electrons of Cu and the Schottky junctions from Ni nanoparticles. This synergy allows the CdS nanosheets to absorb wide-range visible light, separate carriers, and enhance the surface kinetics of H₂ production. In addition, a comprehensive analysis is presented on how Cu–Ni enhances the photocatalytic performance of CdS nanosheets using experimental and DFT calculations. This work offers valuable insights into developing cost-effective plasmonic Cu–Ni bimetal-modified CdS nanosheets, which hold great promise in advancing novel ternary metal–semiconductor photocatalysts for efficient solar energy conversion.