Photocatalytic activities of TiO2 thin films prepared on Galvanized Iron substrate by plasma-enhanced atomic layer deposition

Titanium dioxide (TiO2) thin films were prepared on Galvanized Iron (GI) substrate by plasma-enhanced atomic layer deposition (PE-ALD) using tetrakis-dimethylamido titanium and O2 plasma to investigate the photocatalytic activities. The PE-ALD TiO2 thin films exhibited relatively high growth rate and the crystal structures of TiO2 thin films depended on the growth temperatures. TiO2 thin films deposited at 200 °C have amorphous phase, whereas those with anatase phase and bandgap energy about 3.2 eV were deposited at growth temperature of 250 °C and 300 °C. From contact angles measurement of water droplet, TiO2 thin films with anatase phase and Activ™ glass exhibited superhydrophilic surfaces after UV light exposure. And from photo-induced degradation test of organic solution, anatase TiO2 thin films and Activ™ glass decomposed organic solution under UV illumination. The anatase TiO2 thin film on GI substrate showed higher photocatalytic efficiency than Activ™ glass after 5 h UV light exposure. Thus, we suggest that the anatase phase in TiO2 thin film contributes to both superhydrophilicity and photocatalytic decomposition of 4-chlorophenol solution and anatase TiO2 thin films are suitable for self-cleaning applications.