Plasmon-induced hot carrier separation across multicomponent heterostructure in Ag@AgCl@g-C₃N₄ composites for recyclable detection-removal of organic pollutions via SERS sensing

The global environment is continuously being exposed to toxic organic pollutants, which also greatly threaten human health. Therefore, it is important to develop substrates for detection, identification, and removal of these organic pollutants. In this study, a multifunctional and reusable composite is prepared by anchoring Ag nanoparticles onto Cl-rich g-C₃N₄ nanosheets (Ag@AgCl@g-C₃N₄). The composites present not only excellent surface-enhanced Raman scattering (SERS) performance attributed to enhanced local electric field and SERS-active sites from the constructed structure, but also superior photocatalytic property boosted by the enhanced charge separation efficiency. These exceptional activities allow the composite to be used for detection of methylene blue with a high enhancement factor of 1.39 × 10⁶, and a limit of detection of 1 × 10⁻¹¹ M/L, as well as reusability via photocatalytic degrading the probe molecules, resulting in achieving recyclable SERS sensing applications. Furtherly, the outstanding SERS performance of the composite is demonstrated by recycling detection-degradation process for different molecules with acceptable performance decline. These results indicate that the Ag@AgCl@g-C₃N₄ composite provides a new path for improving traditional single-use SERS substrates and promotes practical SERS applications in sustainable detection and removal of organic pollutants.