Au/MgO/Al2O3 is able to oxidize CO selectively in hydrogen-rich gases (similar to70vol.%) at the temperatures relevant to hydrogen fuel cell applications (70-100 degreesC). The presence of MgO enables the preparation of small, stable An particles on gamma-Al2O3 with high surface area and, in this way, improves both low-temperature CO and H-2 oxidation by O-2 compared to Au/Al2O3. Addition of MnOx and FeOx to Au/MgO/Al2O3 further enhances low-temperature CO oxidation with improved CO2 selectivity. The increase in CO oxidation activity is attributed to the implementation of new routes for supplying active oxygen, e.g., via lattice oxygen. The better CO2 selectivity also probably results from suppression of H-2 oxidation at low temperatures. The results support a model in which CO is adsorbed onto metallic Au or at the Au/MOx perimeter interface and reacts with oxygen also present at the Au/MOx perimeter interface. A focus on decreasing the H-2 oxidation activity is recommended for further catalyst improvement.