Multifunctional GO/Ag/TiO2 nanocomposite for ultrasensitive detection and photocatalytic degradation of hazardous pesticides in food.

A multifunctional GO/Ag/TiO2 nanocomposite was synthesized and characterized using XRD, UV-Vis, HRTEM, and Raman spectroscopy. The material exhibited outstanding (SERS) activity, enabling ultrasensitive detection of the pesticides thiodicarb (TDB) and fenpyroximate (FPM) down to 10-10 M in standard and real vegetable samples (potato, cabbage, broad beans). It also showed high selectivity for Sudan I dye in adulterated masala samples. The calculated SERS enhancement factors were 2.0 × 106 (TDB) and 2.3 × 106 (FPM), with relative standard deviations below 6%, confirming reproducibility and stability. Moreover, the nanocomposite acted as an efficient photocatalyst, achieving 75% and 56% degradation of TDB and FPM respectively under UV light, respectively, following pseudo-first-order kinetics. Total organic carbon analysis indicated effective mineralization, and reactive species studies identified superoxide radicals (O₂•-) as key oxidants. The synergistic effects of GO, Ag, and TiO₂ significantly enhanced both SERS sensitivity and photocatalytic efficiency for food safety and environmental applications.