SnO2 Composite Films for Enhanced Photocatalytic Activities

As a new type of promising semiconductor photocatalyst, SnO2 cannot be widely applied due to its low utilization efficiency to visible light and swift recombination of photogenerated electrons and holes. These drawbacks were effectively overcome by preparing the B/Ag/F tridoped SnO2-ZnO composite films using the simple sol-gel method. The degradation of the methyl green and formaldehyde solutions was used to value the photocatalytic activity of the samples. Photoluminescence (PL) spectra and the UV-Vis absorption spectroscopy results of the samples illustrated that the B/Ag/F tridoped SnO2-ZnO composite film not only improved the lifetime of the charge carriers, but also enhanced their visible light absorption. The X-ray diffraction (XRD) results showed that the crystalline SnO2 was in the structure of rutile. As exhibited in the BET surface area results, the specific surface area of pure SnO(2)was 19.9 m(2) g(-1), while that of the B/Ag/F tridoped SnO2-ZnO was 85.3 m(2) g(-1). Compared to pure SnO2, SnO2-ZnO, or the mono- or di-doped SnO2-ZnO films, the B/Ag/F tridoped SnO2-ZnO composite film had the highest photocatalytic activity.