In order to minimize the charge recombination, a new bilayer TiO2/MgO nanoporous catalyst was fabricated in which the thin layer of insulating MgO on TiO2 acts as electron trap and barrier for recombination, enhancing the overall photocatalytic activity of TiO2. The photocatalytic activity of MgO coated TiO2 has been studied for the oxidation of 2-chlorophenol, 2,4-dichlorophenol (2,4-DCP) and 4-aminobenzoic acid in aqueous solution. The photocatalytic activity is highly dependent on the thickness of the MgO layer and a plausible mechanism of degradation is discussed. (C) 2004 Published by Elsevier B.V.