Preparation and characterization of N-doped visible-light-responsive mesoporous TiO2 hollow spheres

Visible-light-responsive N-doped TiO2 mesoporous hollow spheres were prepared by acid-catalyzed hydrolysis, using carbon spheres obtained by glucose hydrothermal carbonization as a hard template. The spheres were characterized using scanning electron microscopy, transmission electron microscopy, N-2 adsorption desorption isotherms, X-ray diffraction, ultraviolet-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The effects of the N content and calcination temperature on the morphology and photocatalytic activity of TiO2 were investigated. A visible-light response was obtained with TiO2 hollow spheres of diameter 700-850 nm, shell thickness 100 nm, and a bimodal mesoporosity concentrated at 4-6 and 12-14 nm. Phenol degradation of 79.6% was achieved using a catalyst consisting of TiO2 hollow spheres prepared with a Ti:N mass ratio of 1:0.5, and calcined at 600 degrees C. (C) 2014 Published by Elsevier B.V.