In situ SERS monitoring of photocatalysts by Au-decorated Fe3O4@TiO2 nanocomposites: novel perspectives and insights

Abstract

The design and preparation of multifunctional nanomaterials are very important for photocatalytic research. Herein, we successfully fabricated Au-decorated Fe₃O₄@TiO₂ nanoparticles (NPs) that can be easily separated from solution using an external magnet. The synthesized Fe₃O₄@TiO₂–Au NPs exhibit excellent photocatalytic and surface-enhanced Raman scattering (SERS) activities upon 532 nm laser excitation. The photolysis of methyl orange (MO) by the Fe₃O₄@TiO₂–Au NPs was successfully monitored by in situ SERS. The Fe₃O₄@TiO₂–Au NPs exhibit more efficient catalysis than the Fe₃O₄@TiO₂ NPs. Most importantly, Au-decorated TiO₂ exhibits surface plasmon resonance (SPR), which induces hot electron transfer for photocatalytic and SERS activities. Therefore, the proposed Fe₃O₄@TiO₂–Au NPs can be widely used in environmental monitoring and pollutant degradation using an in situ SERS monitoring technique.