Preparation of hollow yttrium-doped TiO₂ microspheres with enhanced visible-light photocatalytic activity

Using melamine-formaldehyde polymer microspheres as templates, yttrium-doped TiO 2 hollow spheres (Y-TiO 2 HS) were successfully prepared via a sol-gel method. The as-syntheszied samples were characterized by Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectrum, luminescence spectrum, specific surface area (BET) analysis and porosity analysis. The results indicate that Y doping could increase the thermal stability, reduce the band gap and enhance photocatalytic activity of the TiO 2 . When the Y doping molar ratio was 1.5%, the Y-TiO 2 HS presented high surface area (62.651 m 2 g −1 ) and photocatalytic degradation rate (about 70%). The corresponding BET value and the degradation rate of Y-TiO 2 HS increased by 3 times and 50%, respectively, compared with those of un-doped TiO 2 HS.