We report on a hydrogen oxidation reaction (HOR) catalyst system composed of gold nanoparticles (Au NPs) and tungsten oxide (WO3). Previously, we reported that Au NPs could be activated for HOR by sonochemical heating and quenching. However, we also found that the activated Au NPs were poisoned by protons, the HOR product. In order to further improve the catalytic behavior of Au NPs, we employed tungsten oxide as a part of the support and a co-catalyst, by which proton spillover could be achieved. Au NPs supported on WO3/C were synthesized. The intermediates and final product were characterized by powder X-ray diffraction, energy dispersive X-ray spectroscopy, and transmission electron microscopy. Electrocatalytic activity of the samples for HOR was investigated by the linear sweep voltammetry with rotating disk electrode technique, which showed the disappearance of the proton poisoning of Au NPs in contact with WO3. Therefore, with sonication treatment, the Au NPs and WO3 composite showed a very high and stable activity for HOR. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.