Hetero-structured TiO2/SrTiO3 nanotube array film with highly reactive anatase TiO2 {001} facets

Interest in highly reactive anatase TiO2 with controllable facets has increased rapidly in recent years because its unique properties provide new insights into the interfacial chemistry of TiO2 in applications such as photocatalysis and in its use as an electrode material. We report here the fabrication of hetero-structured TiO2/SrTiO3 nanotube arrays with a preferred orientation to the anatase TiO2 (001) facet by a typical anodization and subsequent hydrothermal approach, followed by annealing. Based on XRD, FE-SEM, FE-TEM, XPS and Raman measurements, it is shown that TiO2 is partially converted into SrTiO3 attached to in situ TiO2 nanotubes. A hetero-structured interface of TiO2/SrTiO3 with preferred growth of the anatase TiO2 {001} facet was confirmed to be formed after the hydrothermal process. The resulting hetero-structured samples were used as photocatalysts to decolorize methylene blue in aqueous solution in a photocatatytic and photo-electrocatalytic process. The hetero-structured samples show enhanced photocatalytic properties compared with the reference TiO2 nanotube arrays.