Performance data are presented for methane oxidation on alumina-supported Pd, Pt, and Rh catalysts under both fuel-rich and fuel-lean conditions. Catalyst activity was measured in a micro-scale isothermal reactor at temperatures between 300 and 800degreesC. Non-isothermal (near adiabatic) temperature and reaction data were obtained in a full-length (non-differential) sub-scale reactor operating at high pressure (0.9 MPa) and constant inlet temperature, simulating actual reactor operation in catalytic combustion applications.Under fuel-lean conditions, Pd catalyst was the most active, although deactivation occurred above 650degreesC, with reactivation upon cooling. Rh catalyst also deactivated above 750degreesC, but did not reactivate. Pt catalyst was active above 600degreesC. Fuel-lean reaction products were CO2 and H2O for all three catalysts.The same catalysts tested under fuel-rich conditions demonstrated much higher activity. In addition, a `lightoff' temperature was found (between 450 and 600degreesQ, where a stepwise increase in reaction rate was observed. Following 'lightoff' partial oxidation products (CO, H-2) appeared in the mixture, and their concentration increased with increasing temperature. All three catalysts exhibited this behavior.High-pressure (0.9 MPa) sub-scale reactor and combustor data are shown, demonstrating the benefits of fuel-rich operation over the catalyst for ultra-low emissions combustion. (C) 2003 Elsevier B.V. All rights reserved.