Visible-light-driven SnO2/TiO2 nanotube nanocomposite for textile effluent degradation

Abstract

Nanocomposite of SnO₂/TiO₂ nanotube (NT) was prepared by a simple two-step procedure, viz., hydrothermal preparation of TiO₂ NT followed by chemical precipitation of SnO₂ nanoparticle sensitized TiO₂ NT. Transmission electron microscopy analysis revealed that the as-synthesized TiO₂ NTs exhibit a diameter of 20–30 nm and a length of 1–2 μm with a wall thickness of 2–5 nm. The particle size of SnO₂ nanoparticles in the composite was estimated to be 4–6 nm. Both the TiO₂ NT and SnO₂/TiO₂ NT composite were considered for the photocatalytic degradation of textile dye effluent under UV and sunlight irradiation. The SnO₂/TiO₂ NT composite showed improved degradation efficiency. Photoluminescence spectra of SnO₂/TiO₂ NT composites showed a decrease in intensity when compared to the TiO₂ NT – revealing that the rate of recombination is reduced in the SnO₂/TiO₂ NT composite, which is responsible for larger photocatalytic activity. Further, an effluent degradation efficiency of 85% was obtained for the SnO₂/TiO₂ NT composite under sunlight irradiation and this can be considered as one of the best values achieved so far.