Photocatalytic decomposition of nitrous oxide using TiO2 and Ag-TiO2 nanocomposite thin films

TiO2 and Ag-TiO2 (0.05, 0.25 and 1 wt% of Ag) thin films were prepared by the sol–gel method. The prepared films were characterized using SEM-EDAX, XRD, Raman spectroscopy, atomic force microscopy and UV–Vis spectrometry. Photocatalytic decomposition of N2O was performed in an annular batch reactor illuminated with an 8 W Hg lamp (254 nm wavelength). The photoreactivity of Ag-TiO2 increases with the Ag amount to 0.25 wt% Ag. Further increase of Ag loading to 1 wt% Ag did not change N2O conversion. The Ag particles deposited on the TiO2 surface can act as electron–hole separation centers. The presence of water vapor and oxygen in the reaction mixture slightly improved N2O conversion.

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► TiO2 and Ag-TiO2 thin films by dip coating.
► Increase of photocatalytic activity for N2O decomposition with increasing Ag.
► Ag particles on TiO2 surface act as electron–hole separation centers.
► Atomic hydrogen from water vapor as reductant for N2O.