Abstract

A visible-light photoactive TiO_2-xN_x photocatalyst was synthesized successfully by means of cogrinding of anatase-TiO_2(a-TiO_2) in NH_3 ambient, followed by heat-treatment at 200°C in air environment. In general, it is well known that the grinding-operation induces phase transformation of a-TiO_2 to rutile TiO_2. This study investigates the influence of the amount of NH_3 gas on the phase transformation rate of a-TiO_2 and enhancement of visible-light photocatalytic activity, and also examines the relation between the photocatalytic activity and the period of grinding time. The phase transformation rate of a-TiO_2 to rutile is retarded with the amount of NH3 injected. And the visible-light photocatalytic activity of samples, was more closely related to the period of grinding time than NH_3 amount injected, which means that the doping amount of nitrogen into TiO_2 more effective to mechanical energy than NH_3 amount injected. XRD, XPS, FT-IR, UV-vis, Specific surface area (SSA), NOx decomposition techniques are employed to verify above results more clearly.

• Keywords: Grinding;Nitrogen doping;Photocatalyst;NH_3;TiO_2;