Hydrothermally-grown nanostructured anatase TiO2 coatings tailored for photocatalytic and antibacterial properties

Abstract

Low-temperature solution growth of TiO2 films provides unique surface functionalities for base materials that may not survive high processing temperatures. It involves multiple stages of crystal growth at various length scales. Having a fundamental understanding of the mechanisms involved in those stages is essential to obtain desirable functional performances. In this study, we prepared diverse anatase microstructures via a hydrothermal method, all of which start from homogeneous nucleation of the nanoparticles when precursor solution reaches above a critical saturation point. Depending on pH, concentration, temperature and ionic species of precursor solution, however, these primary nanoparticles evolve into different shapes of secondary nanostructures via aggregation of nanoparticles. Thin films of anatase TiO2 consisting of those secondary nanostructures, which have a [001]-texture with (004) surfaces exposed, exhibited the strongest photocatalytic as well as antibacterial properties.