Localized surface plasmon resonance enhanced charge transfer effect in MoO2/ZnSe nanocomposites enabling efficient SERS detection and visible light photocatalytic degradation

The detection of pharmaceutical residues in the environment based on surface enhanced Raman spectroscopy (SERS) technology has become a popular tool due to its superior molecular specificity and high sensitivity. However, the practical applicability of semiconductor-based SERS sensors for trace pharmaceutical contaminants is limited due to their weak and unstable SERS performance. Herein, a donor-bridge-acceptor (D-B-A) system of MoO2 and ZnSe was fabricated to enhance the separation efficiency of electron-hole pairs in ZnSe and the charge transfer between MoO2 and ZnSe, which causes the MoO2/ZnSe nanocomposites to exhibit excellent SERS sensitivity and photocatalytic activity for the detection of multi-component contaminants and the antibiotic. The LOD of ciprofloxacin hydrochloride (CIP HCl) on MoO2/ZnSe nanocomposites is 8.30 x 10-8 M, and the degradation rate of CIP HCl is 80 % after visible light irradiation for 180 min. Our research effectively improves the SERS sensitivities and expands the practical SERS application of plasma-nonmetal/semiconductor compos-ites, and avoids secondary contamination in the detection process. The enhancement mechanism of SERS and the interpretation of photocatalytic phenomena provide promising guidance for providing a low-cost and stable composite SERS platform in the detection and treatment of emerging contaminants.