Preparation of an active SO42-/TiO2 photocatalyst for phenol degradation under supercritical conditions

SO42--doped TiO2 (SO42-/TiO2) nanoparticles (SO42-/TiO2) were prepared by the sol-gel method followed by drying the precursor in supercritical ethanol fluid. During the liquid-phase phenol photocatalytic degradation, the as-prepared SO42-/TiO2 exhibited higher activity and longer lifetime than either the undoped TiO2 or the SO42-/TiO2 obtained through direct drying, apparently as a result of the superiority of the supercritical drying and the promotion of the SO42--dopant. Based on various characterizations including XRD, TEM, XPS, FTIR, and photoluminescence spectra, and FTIR-pyridine thermodesorption, the crystallization degree, the surface area, the pore structure, the surface acidity and the surface electronic state of the as-prepared SO42-/TiO2, samples were investigated and their correlation to the catalytic properties was discussed. (C) 2004 Elsevier B.V. All rights reserved.