Mechanochemical Synthesis and Photocatalytic Activity of Nitrogen Doped SrTiO₃

Abstract

Nitrogen doped SrTiO₃ powders were prepared by mechanochemical reactions in which two kinds of doping sources, hexamethylenetetramine (HMT) and urea, were ground (20 wt.% of these two powders) individually with SrTiO₃ by high energy planetary ball mill. The photocatalytic activity of the nitrogen doped SrTiO₃ powders in both visible light (>400 nm) and near ultraviolet light regions (>290 nm) have been studied. The photocatalytic activity for nitrogen monoxide elimination of SrTiO₃ could be improved greatly by nitrogen doping. Under the irradiation of the light above wavelength 400 nm and 290 nm, the photocatalytic activities of nitrogen doped SrTiO₃ made from 20 wt%HMT-SrTiO₃ were about 2.5 and 1.5 times higher than those of pure SrTiO₃, respectively, and 1.4 and 1.3 times higher than those of commercial titania powder (Degussa P-25). We found that a new absorption edge was formed in the visible light region by nitrogen doping which might be the reason for the high visible light photocatalytic activity of this substance.