Structural and photoelectrochemical dynamics of in-situ hydrogenated anatase TiO2 thin films grown by DC reactive magnetron sputtering

Abstract

Hydrogenation has become one of the most used strategies to improve the photoactive properties of titanium dioxide nanomaterials, n-TiO2. To obtain more information about the hydrogenated process on anatase TiO2 thin films and the improvement of the photoactivity of this material, we report a study on the structural changes of hydrogenated anatase thin films produced by direct-current reactive magnetron sputtering. In the first stage of the hydrogenation process, the obtained polycrystalline anatase films present an increment of the {001} facet according to the amount of hydrogen used in the plasma reaction. At higher hydrogen concentrations, amorphous and rutile phases start to appear. The photoactivity of the hydrogenated anatase samples, H:TiO2, presents a redshift of the photoelectrochemical onset and an increase of the reactivity in the UV region. Both results were experimentally and theoretically related to the formation of the {001} facet and the TiH/TiOH bonds at the surface of the hydrogenated thin films.