Au-buffered WO3 thin films were deposited on quartz glass using a radio-frequency magnetron sputtering method and their optical, structural and photocatalytic properties were investigated. The photocatalytic activity of the prepared thin films was evaluated by measuring the photodecomposition of methylene blue. The presence of the Au buffer layer improved photodegradation efficiency by about 50%, red-shifted the absorption edge to a longer wavelength, and increased the film surface roughness. Photoexcited charges were separated by surface plasmon resonance at Au nanoparticles. (C) 2010 Elsevier B.V. All rights reserved.