Band-gap engineering and comparative investigation of Ti 2 Nb 10 O 29 photocatalysts obtained by Various synthetic routes

Abstract Ti 2 Nb 10 O 29 photocatalysts were successfully synthesized by three different methods. Ti 2 Nb 10 O 29 fabricated by the solvothermal method (ST-TNO) exhibited unique microspheres compared to the larger irregular particles observed for the samples annealed in air (Air-TNO) and Ar (Ar-TNO). X-ray Photoelectron Spectroscopy (XPS) results revealed that a partial reduction process from Ti 4+ into Ti 3+ occurs in Ar-TNO, because of the introduction of oxygen defects. Ar-TNO exhibited visible-light absorption with a band gap of 2.85 eV, while the absorption edges of Air-TNO and ST-TNO were approximately 400 nm. Under UV light irradiation (λ