Ag Nanoparticles Synthesized on Black-Titanium Dioxide by Photocatalytic Method as Reusable Substrates of Surface-Enhanced Raman Spectroscopy

The construction of excellent surface-enhanced Raman spectroscopy (SERS) substrates needs rationally designed architectures of noble metals or semiconductors. In this study, Ag nanoparticles (NPs) are densely and uniformly synthesized on the surfaces of black-titanium dioxide (b-TiO2) NPs through a facile two-step photocatalysis method. The b-TiO2 improved the utilization efficiency of natural sunlight by the extension of light absorption from the ultraviolet (UV) to the visible (Vis) region. First, Ag seeds were densely grown in a short time on the surfaces of b-TiO2 NPs under the irradiation of UV light. Then, Ag NPs were grown slowly and uniformly from the Ag seeds under the irradiation of Vis light. The as-prepared Ag/b-TiO2 with high sensitivity achieved a limit of detection as low as 10(-12) M for rhodamine 6G. Meanwhile, the substrate showed reusability due to the high photocatalytic ability of b-TiO2. The Ag/b-TiO2 SERS substrate achieves SERS detections of organic pollutants, such as hydroquinone, p-phenylenediamine, and terephthalic acid, indicating that this substrate possesses potential applications in food safety and environmental monitoring.

Automated summary

In this study, Ag nanoparticles were densely and uniformly synthesized on the surfaces of black-titanium dioxide nanoparticles through a facile two-step photocatalysis method. The resulting Ag/b-TiO2 substrate showed high sensitivity and reusability, making it suitable for detecting organic pollutants and potentially useful in food safety and environmental monitoring.