Abstract
TiO2 photocatalysts can remove harmful substances such as volatile organic compounds (VOCs) under light irradiation. However, they are only activated by ultraviolet light at wavelengths shorter than about 380 nm, so they cannot be used under visible light irradiation. Thus, visible-light-responsive photocatalysts have been studied extensively to enable their indoor use. TiO2 powder supported with Cu(II) ions (Cu(II)/TiO2) has recently been reported to possess visible-light photocatalytic activity. In the present study, we used cupric acetate as a Cu(II) source. We prepared various Cu(II)/TiO2 photocatalysts by changing the amount of cupric acetate and assessed their photocatalytic performance. The performance of Cu(II)/TiO2 photocatalysts was estimated from the rate of decrease in the formaldehyde (HCHO) concentration in the flowing stimulant air under irradiation by a fluorescent lamp or a white LED. The surface properties of Cu(II)/TiO2 photocatalysts were analyzed by X-ray photoelectron spectroscopy (XPS) measurements. The optical reflectance of Cu(II)/TiO2 photocatalysts was measured by using a UV-Vis spectrophotometer. The maximum visible-light photocatalytic activity was observed at a Cu/TiO2 weight ratio of 5.69 [wt%]. The maximum rate of decrease in the HCHO concentration of the Cu(II)/TiO2 photocatalyst was higher than twice that of a typical commercial TiO2-based visible-light-responsive photocatalyst (Ishihara-Sangyo MPT-623) under the same test conditions. [DOI: 10.1380/ejssnt.2015.143]
