Intergrowth and coexistence effects of TiO₂–SnO₂ nanocomposite with excellent photocatalytic activity

Graphical abstract: A model of intergrowth and coexistence effects of optimized anatase–rutile phases TiO₂–SnO₂ catalyst which exhibits higher photocatalytic activity than TiO₂-P25. - Highlights: • The TiO₂–SnO₂ nanocomposite was synthesized via novel Sol–hydrothermal Technique. • SnO₂ adding can accelerate the anatase-to-rutile transformation greatly. • The photocatalytic property was studied upon UV irradiation. • TiO₂–SnO₂ compounds show superior photocatalytic activity. • The intergrowth and coexistence effects explain excellent photocatalytic activity. - Abstract: The TiO₂–SnO₂ nanocomposite with excellent photocatalytic activity was synthesized via sol–hydrothermal process. The obtained samples were characterized by XRD, FETEM, LRS and UV–vis DRS. The photocatalytic activities of as-prepared samples were investigated by degradation of methyl blue (MB) under UV illumination. The results clearly indicate that a small quantity of SnO₂ adding can accelerate the anatase-to-rutile transformation greatly, and the nanocomposites consisting of anatase (A) and rutile (R) phases are formed in the molar ratios Ti:Sn = 20:1, 60:1 and 80:1, respectively. They show the higher photocatalytic activity than that of TiO₂ (A). Remarkably, they can be enhanced up to several times compared with TiO₂-P25. Especially, the catalyst of molar ratio Ti:Sn = 60:1 is found to be the most efficient, it exhibits a complete decomposition of MB within 20 min under UV irradiation. The results are explained by taking into account the intergrowth and coexistence effects of optimized anatase–rutile phases TiO₂–SnO₂ catalyst, the larger specific surface area and Quantum-sized TiO₂–SnO₂ particles obtained from the sol–hydrothermal method