Multifunctional Ni(OH)2/Ag composites for ultrasensitive SERS detection and efficient photocatalytic degradation of ciprofloxacin and methylene blue

To enable the widespread application of surface-enhanced Raman scattering (SERS) technique in practical sensing of organic pollutants, it is essential to develop a reliable SERS substrate that offers both high sensitivity and reusability. In this study, we employed a simple and rapid in-situ deposition method to coat Ag nanoparticles onto flower-like Ni(OH)2 spheres, resulting in the formation of Ni(OH)2/Ag composites with excellent photocatalytic performance and SERS activity. These composites were used as a promising SERS analysis tool for effective detection of organic pollutants, including ciprofloxacin hydrochloride (CIP) and methylene blue (MB). Notably, the composites exhibited outstanding detection limits of 10−8 M for MB and 10−7 M for CIP, respectively, and showed a strong linear relationship between SERS intensities and the logarithmic concentration (R2 ≥ 0.97). Moreover, under simulated sunlight irradiation, the Ni(OH)2/Ag composites efficiently degraded MB and CIP molecules within a short period of 120 min for MB and 130 min for CIP. This demonstrated their practical reusability, as evidenced by their consistent performance over five cycles of SERS sensing. These findings underscore the significant potential of these composites for SERS-based detection of trace pollutants and ecological restoration through photocatalytic reactions in the future.