PVP (polyvinylpyrrolidone)-doped SnO2/TiO2 composite thin films and undoped films were prepared by sol-gel and dip-coating methods. The calcined films at 600 oC for 2 h were characterized by scanning electron microscopy, X-ray defractometer, UV-Vis spectroscopy, and X-ray photoelectron spectroscopy. Furthermore, the photocatalytic reaction on the degradation of methylene blue dye solution was also investigated in order to observe the correlation between the results of bacteria inactivation of the prepared films and that of photocatalytic activity on methylene blue degradation. The PVP-doped SnO2/TiO2 composite thin films and undoped films were preliminarily studied against gram negative Escherichia coli and gram positive Staphylococcus aureus bacteria. It revealed that PVP-doped SnO2/TiO2 composite films resulted in shifting the absorption wavelength towards narrowing the energy band gap, high crystallinity of anatase phase, and small crystallite size. Therefore, the 40PVP/SnO2/TiO2 composite thin film exhibited greater photocatalytic activity and water disinfection efficiency than those of undoped films.
