CATALYTIC BEHAVIOR OF NOBLE-METAL REDUCIBLE OXIDE MATERIALS FOR LOW-TEMPERATURE CO OXIDATION .1. COMPARISON OF CATALYST PERFORMANCE

MnOx, Ag/MnOx, Au/MnOx, Cu/MnOx, Pd/MnOx, Pt/MnOx, Ru/MnOx, Au/CeOx, and Au/Fe2O3 were synthesized and tested for CO oxidation activity in low concentrations of stoichiometric CO and O2 at 30-75-degrees-C. Catalytic activity was measured for periods as long as 18 000 min. At 75-degrees Au/MnOx is most active sustaining nearly 100% CO conversion for 10 000 min. It also retains high activity at 50 and 30-degrees-C with negligible decay in activity. Other catalysts including Au/CeOx and Au/Fe2O3 also perform well. The Cu/MnOx exhibits a high initial activity which decays rapidly. After the decay period the activity remains very stable, making Cu/MnOx a potential candidate for long-term applications such as CO2 lasers in space.