Influence of the structural characteristics of epitaxial TiO2 thin films on their photocatalytic properties
Abstract
This paper describes the photocatalytic behavior of epitaxial anatase TiO2 thin films, using the azodye golden yellow remazol RNL 150% as a probe molecule. The films were deposited by pulsed laser deposition on various single crystal substrates as well as on amorphous SiO2 for comparison. It was observed that the nature of film-substrate interaction and the stress provoked by the substrate play important roles in photocatalytic properties. Indeed, the film grown on (100) SrTiO3 presented a very poor photocatalytic activity (33% of discoloration), which can be related to the charge distribution in the SrTiO3/TiO2 interface. The film deposited on (100) LaAlO3 showed a low activity (50% of discoloration) attributed to a highly stressed structure. The best photocatalytic performance (80% of discoloration) was achieved with a film grown on C-sapphire presenting a large amount of (001) anatase with a low amount of (100) rutile. High photocatalytic activities were also obtained with (100) anatase (with two in-plane orientations) on (100) MgO and with randomly oriented films on silica (61% and 70% of discoloration, respectively). Copyright © 2017 American Scientific Publishers.