In-situ SERS study of surface plasmon resonance enhanced photocatalytic reaction using bifunctional Au@CdS core-shell nanocomposite
Surface plasmon resonance (SPR) has been utilized in many fields, such as surface-enhanced Raman spectroscopy (SERS) and solar energy conversion. Here we developed a Au@CdS core-shell nanostructure, a bifunctional nanoparticle, used as efficiet catalyst for SPR enhanced photocatalytic degradation, and as a substrate for in-situ SERS detection of methylene blue (MB) and p-nitrophenol (pNTP). With integration of a Au nanoparticle into a CdS shell, degradation process was significantly accelerated under 500 nm long-pass (λ 500 nm) visible light irradiation, which was caused by the injection of hot electrons. Moreover, a highly uniform, monolayer film of Au@CdS nanoparticles (NPs) has been prepared and used as both SERS substrate and catalyst. The decomposition of MB molecules and nitrogen coupling reaction of PNTP were observed during the 638 nm laser illumination. We demonstrate that the plasmonic core-semiconductor shell nanocomposite can be a promising material for photocatalysis and in-situ SERS study.