Band-engineered SrTiO3 nanowires for visible light photocatalysis

Abstract

We have theoretically investigated the structural, electronic, and optical properties of perovskite SrTiO3 nanowires for use in visible light photocatalytic applications using pseudopotential density-functional theory calculations. The electronic structure calculations show that the band gap is modified in the SrTiO3 nanowires compared with that of the bulk. For TiO2-terminated nanowires, the mid-band states induced by the combination of oxygen and strontium atoms on the surface lead to a shift in the valence band toward the conduction band without interference from the edge of the conduction band, which reduces the band gap. On the contrary, the electronic states induced by the combination of oxygen and strontium atoms on the surface of SrO-terminated nanowires lead to a shift in the conduction band toward the valence band. The calculated optical results indicate that the absorption edge of the nanowires shift towards the red-light region. These theoretical results suggest that perovskite SrTiO3 nanowires are promising candidates for use in visible light photocatalytic processes such as solar-assisted water splitting reactions.