In-situ formation of carboxylate species on TiO2 nanosheets for enhanced visible-light photocatalytic performance

Abstract

It still remains challenge for expanding the photo-response range of TiO2 with dominant {0 0 1} facets due to the hardly achieving modification of the electronic structure without destroying the formation of TiO2 high energy facets. Herein, we report the construction of carboxylate species modified TiO2 nanosheets with dominant {0 0 1} facets by employing ethanol as a carbon source through a low-temperature (300 °C) carbonization method. The as-obtained samples were investigated in detail by using various characterization techniques. The results indicate that the carboxylate species derived from the oxidation and carbonization of ethanol are coordinated to the {0 0 1} facets in a bidentate bridging mode. The electron-withdrawing carboxylate species induce TiO2 to form a lower valence band edge and a narrower bandgap, which enhances the oxidation ability of photogenerated holes and expands the photo-response range. The partially carbonized carboxylate species can also act as a photosensitizer to induce visible-light photocatalytic activity of TiO2 nanosheets. In addition, the carboxylate species can further promote the separation of photogenerated charge carriers. The findings of this work may provide a new perspective for tuning the band structure of TiO2 with dominant {0 0 1} facets and improving its photocatalytic performance.