Preparation and application of visible-light-responsive Ni-doped and SnO2-coupled TiO2 nanocomposite photocatalysts

A new series of visible-light-driven TiO2 photocatalysts constituting lattice-doped Ni and surface-coupled SnO2 nanocomposites, xNi-TiO2-SnO2 (x = 0.1, 0.3, 0.5), were synthesized. TiO2 and xNi-TiO2 were prepared by a sol-gel method while the SnO2 was coupled to these via a ligand exchange reaction and finally the catalysts were thermally treated. The presence of Ni ions in the lattice of the photocatalysts was indirectly confirmed by a red shift in DRS spectra. XRD showed crystalline peaks only assignable to TiO2 anatase phase. XPS analysis confirmed that Sn is present on the surface of the catalysts as SnO2 while Ni2O3 is absent. The xNi-TiO2-SnO2 nanocomposites showed a promising visible-light-responsive photocatalytic activity and were found superior to TiO2, xNi-TiO2 and TiO2-SnO2 for the degradation of toluene in air.