A new gold catalyst was synthesized by deposition-precipitation of gold hydroxide on thoria. The catalyst showed extremely high catalytic activity at the lowest possible temperature for carrying out of water-gas shift reaction (WGSR) under experimental conditions. The measured degree of CO conversion at 393 K (GHSV = 4000 h(-1)) was 84%. The effect of space velocity and water vapor partial pressure on WGS activity was studied at different temperatures. The catalytic measurements testified high stability of Au/ThO2. HRTEM combined with EDS, X-ray diffraction and H-2-TPR techniques were used for the catalyst characterisation. Detailed FTIR measurements of adsorbed CO at different temperatures on oxidized and reduced catalyst were performed. FTIR spectra were also collected during CO + O-2 interaction at different temperatures, CO oxidation in the presence of hydrogen (PROX) and WGSR. Preliminary catalytic tests for CO oxidation in hydrogen-rich gas stream revealed that Au/ThO2 could be of interest as potential catalyst for the PROX process. (c) 2005 Elsevier B.V. All rights reserved.