Synthesis of mesoporous TiO2 photocatalytically active under visible light or UV radiation

Abstract

Mesoporous nanosized titania with a high specific surface area is synthesized by titanium carbide oxidation with nitric acid followed by a heat treatment of the product. The effect of heating temperature on the structural characteristics of TiO2 and its activity in the photodecomposition reaction of the dye (rhodamine B) is studied. It is shown that compared with the well-known photocatalyst, Degussa P25, the photocatalytic activity of the samples heat-treated at 200°C and 400 °C is improved, when exposed to visible and UV radiation, respectively. The high photoactivity of the TiO2 sample (200°C) under exposure to visible light is due to a high specific surface area, the presence of COx and NOx groups on the surface, and the structure of the anatase phase with a trace of rutile phase. Under exposure to the UV radiation, the TiO2 sample (400°C) is characterized by high photoactivity attributed to a high specific surface area and oxygen structure defects (O−).