Photo-oxidation properties of nitrogen doped SrTiO3 made by mechanical activation

Nitrogen doped SrTiO3 powders were prepared by mechanochemical reaction of SrTiO3 and 20 wt.% of three kinds of doping sources, hexamethylenetetramine, urea and ammonium carbonate using a high energy planetary ball mill. The effects of several factors such as the kinds of nitrogen doping source, milling time, content of nitrogen source in the raw material, post-grinding heat treatment temperature and post-grinding beat treatment atmosphere on the photocatalysis of the samples have been studied. The nitrogen doped SrTiO3 had yellow color and possessed two absorption edges around 390 and 470 nm. The sample prepared by grinding the mixture of 20 wt.% hexamethylenetetramine-80 wt.% SrTiO3 followed by heat treatment at 400 degreesC in air showed the best performance in the elimination of NO. The value of NO destruction under visible light (lambda > 400 nm) irradiation attained to 47.8%, which was about 3.5 and 1.4 times higher than that of pure SrTiO3 and commercial titania (Degussa P-25). (C) 2004 Elsevier B.V. All rights reserved.