Enhanced photocatalytic performance of Bi4Ti3O12 nanosheets synthesized by a self-catalyzed fast reaction process.

Abstract Single-crystalline Bi 4 Ti 3 O 12 nanosheets with the exposed {001} facets have been successfully prepared using a novel self-catalyzed reaction route, which involves a fast reaction of Bi 2 O 3 and TiO 2 at 280 °C with the critical assistance of tartaric acid. It is believed that the formation of Bi 4 Ti 3 O 12 nanosheets is driven by the massive heat released during the oxidation of tartaric acid when Bi 2 O 3 and TiO 2 are mixed. With this simplified novel process, the synthesis of high quality Bi 4 Ti 3 O 12 photocatalyst can be accomplished at low temperatures of 280 °C in less than 10 min. The as-obtained optimum nanosheet photocatalyst exhibits high visible light photodegradation of methyl orange, indicated by the 3.92 times higher efficiency than that of the Bi 4 Ti 3 O 12 nanosheets prepared by a widely acknowledged molten salt method. In addition, this Bi 4 Ti 3 O 12 nanosheet photocatalyst presents high recycling ability and storage stability. The X-ray photoelectron spectrometer and electron paramagnetic resonance analyses reveal that oxygen vacancies are produced on the surface of as-prepared Bi 4 Ti 3 O 12 nanosheets after the self-catalyzed reaction, which then extend the valence band width and reduce the band gap of the Bi 4 Ti 3 O 12 photocatalyst. It is therefore concluded that the much enhanced photocatalytic activity of the as-prepared catalyst is the synergistic effects of the valence band widening that increases the separation efficiency of the photo-generated carriers and the band gap narrowing that broadens the absorption edge of light. [ABSTRACT FROM AUTHOR]