MoO3 nanosheet-assisted photochemical reduction synthesis of Au nanoparticles for surface-enhanced Raman scattering substrates

Innovation in gold nanoparticles (AuNPs) preparation is fundamental for realization of various functionalities. Thus, the development of robust strategies for synthesizing AuNPs is attractive. Herein, we experimentally demonstrate a facile method for AuNPs synthesis based on two-dimensional semiconductor molybdenum oxide (MoO3), combined with a photochemical process. In this synthesis route, MoO3 nanosheets are used as electron carriers and sacrificial templates to direct the wet-chemical epitaxial growth of AuNPs under ultraviolet (UV) irradiation without requiring another chemical reducing agent or stabilizer. The as-synthesized AuNPs were extensively characterized to investigate their formation mechanism. As a proof of concept, as-synthesized AuNPs were employed as homogeneous surface-enhanced Raman scattering (SERS)-active substrate to construct a detection platform for malachite green (MG) pigment. The SERS detection method was also evaluated by quantitative analysis of MG in real fish samples. We believe that templating with MoO3 nanosheets and using UV-assisted photochemical reduction to prepare AuNPs via a wet-chemical reaction is a promising strategy, which is expected to be applicable to the production of other novel noble metal functional nanomaterials.