Surface-enhanced Raman scattering (SERS) technology has emerged as a powerful analytical tool for trace-level environmental pollutant detection, with its performance critically dependent on the physicochemical properties of substrate materials. While noble metal substrates (e.g., Au/Ag) demonstrate superior SERS enhancement through surface plasmon resonance (SPR), their practical deployment is hampered by inherent limitations including high material costs and susceptibility to oxidation-induced degradation. Herein, we report the rational design of Ag2O/TiO2 composite substrates via a facile wet-chemical precipitation method, wherein Ag2O nanoparticles are uniformly decorated onto pre-synthesized TiO2 nanospheres. Upon application in crystal violet (CV) detection, the optimized Ag2O/TiO2 composite substrate exhibits remarkable SERS performance with an enhancement factor (EF) of 6.7 × 106 and an ultra-low detection limit (LOD) of 1.0 nM (1.0 × 10⁻9 M). Systematic investigations reveal that the Ag2O modification induces photogenerated electron accumulation on the TiO2 surface, promoting photoinduced charge transfer (PICT) between the substrate and adsorbed CV molecules. This work not only presents a cost-effective and stable SERS platform for environmental contaminant monitoring but also provides mechanistic insights into the rational engineering of semiconductor-based SERS substrates with enhanced sensitivity and durability.
Wang et al. (Sun,) studied this question.