TiO2 nanorods grown by hydrothermal method and their photocatalytic activity for hydrogen production.

Highlights • TiO 2 thin films were grown by sputtering method and use as seed layer to grow TiO 2 nanorods by means of hydrothermal method. • TiO 2 nanorods has 3.5 higher activity (132 μmol) than TiO 2 seed layer (38 μmol). • TiO 2 nanorods has the contribution of Ti3+ species, which reduce the band gap value and improve the photocatalytic activity. Abstract TiO 2 nanorods were prepared by hydrothermal method over TiO 2 seed layers deposited by DC Sputtering. From the XRD structural characterization, it has been stated that TiO 2 seed layer present mainly the anatase phase with some contributions of rutile phase, while for TiO 2 nanorods, the rutile phase is present. The thin film thickness were measured using a profilometer, resulting in a thickness of 310 nm for the seed layer and ∼400 nm for TiO 2 nanorods. PL analysis for both films presented an indirect transitions Γ 1b → Χ 2a, as well as oxygen vacancies, defects and surface states. Photocatalytic H 2 production for TiO 2 seed layer film was around 38 μmol, while TiO 2 nanorods produced 132 μmol. This is attributed to the increase to the midgap states present below the conduction band and near to the valence band, which help to improve the photocatalytic activity. [ABSTRACT FROM AUTHOR]