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

Abstract

Titanium dioxide (TiO2) thin films were prepared on Galvanized Iron (Cl) substrate by plasma-enhanced atomic layer deposition (PE-ALD) using tetrakis-dimethylamido titanium and O-2 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 degrees C have amorphous phase, whereas those with anatase phase and bandgap energy about 3.2 eV were deposited at growth temperature of 250 degrees C and 300 degrees C. From contact angles measurement of water droplet, TiO2 thin films with anatase phase and Activ (TM) glass exhibited superhydrophilic surfaces after UV light exposure. And from photo-induced degradation test of organic solution, anatase TiO2 thin films and Activ (TM) glass decomposed organic solution under UV illumination. The anatase TiO2 thin film on GI substrate showed higher photocatalytic efficiency than Activ (TM) 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. (C) 2010 Elsevier B.V. All rights reserved.