Synthesis and evaluation of optical and antimicrobial properties of Ag-SnO2 nanocomposites

Abstract We report on the sol-gel based room temperature synthesis of undoped SnO 2 and Ag-SnO 2 nanostructures. The synthesized nanostructures were characterized by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, High-resolution transmission electron microscopy (HR-TEM) and UV–visible spectroscopy. The XRD pattern confirmed that the obtained nanostructures have a tetragonally rutile structure. No extra phase changes were observed after Ag doping. UV–visible spectroscopy measurements indicated that the band gap of 3.59 eV for pure SnO 2 nanostructures, decreased to 3.39 eV after doping. TEM analysis showed that no regular shape morphology existed and some rod-shaped particles were also detected in the nanostructures. The antibacterial activity of the nanostructures against E . coli was evaluated and a continuous decrease of microbial count was observed. The microbial population decreased from 6 × 10 5  cfu/ml to 7 × 10 4  cfu/ml and 5 × 10 4  cfu/ml on SnO 2 and Ag-SnO 2 treatments, respectively. Thus, the nanostructures can be used for the biorational management of E. coli for waste water treatment before discharge.