Abstract: The Au/TiO2 photocatalyst was prepared by the deposition-precipitation method and was characterized by UV-Vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The influence of water vapor at room temperature on the photocatalytic activity of Au/TiO2 for ozone decomposition was studied. The results showed that the catalytic activity of Au/TiO2 decreased significantly when water vapor was introduced into the dried feed gas. In addition, the ozone removal rate over Au/TiO2 reached a steady value rapidly. The results of O 1s and Au 4f XPS showed that the surface structure of TiO2 was changed, and the interaction between the gold and the support was weakened in the presence of water vapor, which was responsible for the decrease in the photocatalytic activity of the catalyst.

Key words: room temperature water vapor, gold, titania, photocatalytic decomposition, ozone