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

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 {0 0 1} 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 {0 0 1} facet and the TiH/TiOH bonds at the surface of the hydrogenated thin films.