Photocatalytic and Antibacterial Properties of TiO2 Composite Thin Films Coated on 304 Stainless Steel Substrate Synthesized at Low Temperature

This paper describes the photoactive and antibacterial properties of TiO2, Fe3+/TiO2 and N/TiO2 thin films on 304 stainless steel substrate that prepared by a sol-gel and dip coating methods. Anatase phase crystalline together with an amorphous phase was formed after refluxed at 100W for 2h using a domestic microwave oven followed by oven heating in low temperature range 100-250°C for 1 h. The adhesion between thin film and stainless steel substrate is strong and films thickness observed by SEM were about 700~1000 nm. FT-IR spectra of as-prepared TiO2 powders reveal hydroxyl radical on TiO2 surfaces, leading to promotion of photocatalytic reaction of the films. Photocatalytic activity was determined by means of degradation of methylene blue solution under UV irradiation and antibacterial efficiency was evaluated by inactivation of E.coli. The photocatalytic reaction rate can be expressed as an exponential equation. TiO2 and TiO2 composite thin films exhibited high photoactive and antibacterial properties under UV irradiation comparing to control. E.coli was killed about 80% and 95% during treatment with UV for 1 and 3 h, respectively.