Titanium dioxide functionalized with Keggin type polyoxometalate (POMs) [Xn+W12O40]((8-n)-) (XW12; Xn+ = P5+, Si4+, Ge4+) were prepared by sol-gel method. The Keggin structure and dispersion state of POMs were monitored by FT-IR and XRD. The composites showed higher photocatalytic activity than pure TiO2, pure POMs or mechanical mixture of TiO2 and POMs for X-3B degradation. Among the three POMs-TiO2 hybrid materials, the reactivity was: PW12 > SiW12 > GeW12. With different loading weights for the same POMs, the reactivity followed the order: 30 wt.% > 15 wt.% > 45 wt.%. (c) 2006 Elsevier B.V. All rights reserved.