Structure and photocatalytic characteristics of TiO2 film photocatalyst coated on stainless steel webnet

Abstract

Abstract High photocatalytic activities of TiO 2 films (50–360 nm) were coated on stainless steel webnet by the sol–gel method. Stainless steel webnet is a good substrate due to its large surface area, good ventilation for gases passing and good utilization of UV light. The TiO 2 films exhibited a uniform anatase structure with particle size about 10 nm. The photocatalytic activity of the TiO 2 film coated on stainless steel webnet can be related to its crystallization and thickness. With increasing of thickness of the TiO 2 film, the diffusion of the substrate was restricted from the surface and a more perfect crystallization of TiO 2 film was formed. Thicker and better crystallization of TiO 2 film resulted in its higher photocatalytic activity, which was evaluated by the photocatalytic oxidation of gaseous formaldehyde in a cylindrical flowing photoreactor. When the TiO 2 film thickness exceeds a certain value (about 250 nm), its photocatalytic activity remains unchanged. This indicated that only a certain thickness of the TiO 2 film was effective on the photocatalytic reaction.