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

Abstract

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 photocatalytic and photoelectrocatalytic process. The hetero-structured samples show enhanced photocatalytic properties compared with the reference TiO₂ nanotube arrays.