Lanthanum and nitrogen co-doped SrTiO3 powders as visible light sensitive photocatalyst

Lanthanum and nitrogen co-doped SrTiO3 was prepared by a mechanochemical reaction method using SrTiO3, urea and La2O3 as the raw materials. Nitrogen-doped SrTiO3 could be prepared by heating the mixture of SrTiO3 and La2O3 under flowing NH3 gas at 600 degrees C. The sample prepared with 0.2 mol% La2O3, 22 mol% urea and 77.8 mol% SrTiO3 which has nearly the same nitrogen and lanthanum doping atomic fractions could be obtained by a mechanochemical method and exhibited high photocatalytic activities. Under the irradiation of light with wavelengths larger than 400 and 290 nm, the photocatalytic activity of nitrogen and lanthanum co-doped SrTiO3 was 2.6 and two times greater than that of pure SrTiO3. A new absorption edge, which was formed in the visible light region and higher visible light absorption after co-doping were the reason for the high visible light photocatalytic activity of this substance. (c) 2004 Elsevier Ltd. All rights reserved.