Enhanced visible-light activity of Ti3+ self-doped TiO2 with co-exposed {001} and {101} facets

The Ti3+ self-doped titanium dioxide (TiO2) nanosheets with co-exposed {001} and {101} facets were successfully synthesised by the one-step solvent thermal method. The as-prepared samples were characterised by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy. The results showed that the Ti3+ self-doped TiO2 nanosheets with anatase structure exposed {001} and {101} facets. XPS spectra confirmed Ti3+ were self-doped TiO2 nanosheets, and which narrowed the band gap of TiO2. Comparing to bare TiO2, the Ti3+ self-doped TiO2 nanosheets exhibited excellent photocatalytic activities. The reasons were that the co-exposed {001} and {101} crystalline facet effectively improved the separation efficiency of photogenerated electron–hole pairs, and the existence of Ti3+ and oxygen vacancy resulted in a narrowing band gap and enhancing visible absorption.