Synergetic effect of surface plasmon resonance and Schottky junction to drastically boost solar-driven photoelectrochemical hydrogen production and photocatalytic performance of CdS/Al nanorod arrays

Photocatalysis is considered as an effective approach to solve the shortages of energy and the pollution problems of environment, because it is a green and sustainable method for utilizing solar energy to produce hydrogen (H-2) or to degrade organic contaminants in wastewater. Here, a novel photocatalyst fabricated by decorating CdS nanorod arrays (NRAs) with non-noble metal plasmonic Al nanoparticles (NPs) (CdS/Al NRAs) was designed to substantially boost the solar-driven photoelectrochemical (PEC) H-2 evolution and photocatalytic activities. The constructed CdS/Al NRAs demonstrated substantially enhanced PEC H-2 evolution and photocatalytic performances. Without external bias, the fabricated CdS/Al NRAs with optimized loading of Al NPs exhibited a sub-stantially enhanced H-2 production rate of 90.7 mu mol h(-1) under simulated solar light irradiation (100 mW cm(-2)), 3.2 times higher than the pristine CdS NRAs. In addition, the degradation efficiency of Congo red over CdS/Al NRAs reached up to 92.0%, 2.1 times that of the pristine CdS NRAs. The photoluminescence and Mott-Schottky measurements evidently revealed that the hot electron of Al was injected into CdS due to the surface plasmon resonance (SPR) effect. Additionally, the Mott-Schottky tests confirmed the establishment of Schottky barrier in CdS/Al NRAs, prohibiting the injected hot electrons from returning to Al NPs. The experiments evidently demonstrated that the SPR effect and Schottky junction were simultaneously integrated into the constructed CdS/Al NRAs. The synergetic effect of SPR and Schottky junction induced the effective injection of hot electrons and separation of photogenerated charges, leading to substantially enhanced PEC H-2 evolution and photo -catalytic performances. This work provides a new approach to enhance the PEC H-2 evolution and photocatalytic performances of the photocatalyst by using non-noble Al NPs as a plasmonic sensibilizer.