A new method to dope Zn2+ ions only onto the surface of titanium dioxide is proposed here. The photocatalyst TiO2(-Zn) exhibits higher photocatalytic activity than pure TiO2 for the degradation of methyl orange in water. The activity increases when separate ZnO phase is removed via an acid treatment. The results of FT-IR, XRD, AAS and XPS analysis show that the Zn2+ ions are located on the surface of TiO2 nanoparticles and bonded with oxygen atoms around it. The Zn2+ ions on the surface inhibit electron-hole pair recombination as a charge separation center. (C) 2004 Elsevier B.V. All rights reserved.