Nanostructured alpha-Mn2O3 materials have been employed as supports for anchoring gold nanoparticles, which exhibited high activities for low-temperature CO oxidation in the absence or presence of excess H-2. The specific activity was found to increase with gold loading up to 5 wt%. Comparing the specific rates for CO oxidation (ca. 1.50 mmol(CO) g(Au)(-1) s(-1) at 25 degrees C) with the highly active An catalysts in the Au current literature confirmed the exceptionally high activity of these new materials. The rate of CO oxidation showed about half-order dependence of CO partial pressure and was nearly independent of O-2 concentration. X-ray photoelectron spectroscopy combined with in situ CO adsorption studies revealed the presence of both metallic and positively charged gold species in the catalyst under reaction conditions. As compared with the coprecipitation-derived Au-MnOx catalyst, the superior activities of Au/alpha-Mn2O3 have been attributed to its unique redox properties and the facile formation of activated oxygen species on the surface, (c) 2008 Elsevier Inc. All rights reserved