Doping-induced band-gap shrinkage to modify the electronic structure of MoS₂ for organic wastewater management

MoS₂, with its high specific surface area and tunable electronic structure, has received much interest in the fields of sensing and environmental remediation. Nevertheless, pure MoS₂ has the disadvantages of easy aggregation and high electron-hole pair complexity, which affect its SERS and photocatalytic performance. In this work, a band-gap shrinkage strategy was used to improve MoS₂ performance for SERS and photocatalytic applications. It exhibited high SERS activity (enhancement factor (EF) = 3.61 × 10⁸), great stability (4 mth), broad applicability (CV, CR and R6G), and excellent reusability (with a recovery of 95% after 5 cycles). In addition, the interfacial dipole-dipole interaction and charge transfer (CT) process caused by doping Ru together enhanced the SERS sensitivity, reducing the limit of detection of CV to 10¹¹ M. The degradation rate of 10^-5 M CV was up to 99% after 60 min of Ru-MoS₂ photocatalytic degradation under visible light. This study investigated the effect of doping-induced bandgap shrinkage on charge transfer (CT), providing new insights into improving the sensitivity of semiconductor SERS substrates for efficient low-concentration SERS detection and low-cost sustainable wastewater remediation.