Preparation and enhanced daylight-induced photocatalytic activity of C,N,S-tridoped titanium dioxide powders

Abstract

A simple method for preparing highly daylight-induced photoactive nanocrystalline C,N,S-tridoped TiO 2 powders was developed by a solid-phase reaction. The as-prepared TiO 2 powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra, N 2 adsorption–desorption measurements and transmission electron microscopy (TEM). The photocatalytic activity was evaluated by the photocatalytic oxidation of formaldehyde under daylight irradiation in air. The results show that daylight-induced photocatalytic activities of the as-prepared TiO 2 powders were improved by C,N,S-tridoping. The C,N,S-tridoped TiO 2 powders exhibited stronger absorption in the near UV and visible-light region with red shift in the band-gap transition. When the molar ratio of CS(NH 2) 2 to xerogel TiO 2 powders (prepared by hydrolysis of Ti(OC 4H 9) 4 in distilled water) ( R) was kept in 3, the daylight-induced photocatalytic activities of the as-prepared C,N,S-tridoped TiO 2 powders were about more than six times greater than that of Degussa P25 and un-doped TiO 2 powders. The high activities of the C,N,S-tridoped TiO 2 can be attributed to the results of the synergetic effects of strong absorption in the near UV and visible-light region, red shift in adsorption edge and two phase structures of un-doped TiO 2 and C,N,S-tridoped TiO 2.