Visible-light-driven SnO sub(2)/TiO sub(2) nanotube nanocomposite for textile effluent degradation

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