Sol-gel synthesis of mesoporous hollow titania microspheres for photodegradation of 4-chlorophenol

Abstract

Mesoporous titania (TiO₂) hollow microspheres have been prepared by sol-gel method and characterized by XRD, Raman, FTIR, N₂ adsorption-desorption study, FESEM, TEM and UV-DRS. The FESEM images reveal hollow spherical shaped particles of size 2&ndash;4 &micro;m. The BET surface area, total pore volume and average pore diameter of 400 &deg;C-treated sample are found to be 74.52 m² g^-1, 0.23 cm³ g^-1 and 12.37 nm, respectively. The band gap energy of the product is calculated as 3.06 eV. The prepared TiO₂ hollow spheres show ~90% photodegradation of the water pollutant, 4-chlorophenol, within 1 h. The photocatalytic reaction shows pseudo-first order reaction with a rate constant of 0.027 min^-1. The photocatalytic experiments repeated for another three cycles showed no significant changes in the <em>k</em> (min^-1) values, indicating the potential reusability of the material.