Nano-tungsten trioxide (n-WO3) was synthesized by dehydrating tungstic acid (H2WO4) at 300 degrees C. Nano-palladium (n-Pd) was then loaded as 10wt% on this n-WO3 by impregnation for the synthesis of the desired n-Pd/n-WO3 photocatalyst. This loading process enhanced the photocatalytic activity of n-WO3 for the removal of Escherichia coli microorganism from water when applying 355-nm UV laser radiation. The absorption and photoluminescence spectra revealed a blue-shift for the band gap energy (E-g) from 2.71 eV for the undoped n-WO3 to 3.5 eV for the doped one. This shift in E-g caused a near resonance condition, which accounts for the significant improvement of the photocatalytic activity upon doping n-WO3. (C) 2010 Elsevier B.V. All rights reserved.