Development of fuel cell catalysts for elevated temperature applications requires electrochemical techniques able to simulate these conditions. A dual electrolyte flow cell (DEFC) technique has been developed, capable of independent half-cell measurements of methanol oxidation and poisoning adlayer coverage in supported catalyst layers over a wide range of temperatures (25-100 °C) and pressures (0-2.5 atm gauge) at ~100% catalyst utilization while maintaining potential control at all times.@footnote 1@ Recent measurements indicate that increasing the temperature from 50 to 100 °C at 0.35 V@sub PdH@ results in substantial increase in methanol electro-oxidation rates with a ~70 kJ/mol activation energy yet only slight variation in the measured adlayer charge. Tafel slope and stripping charge results at 100 °C indicate the onset of significant CO electro-oxidation rates at 0.33 V@sub rhe@. High CO@sub 2@ yields measured at 100 °C and potentials less than 0.33 V@sub rhe@ indicate a possible role of CO thermal desorption or parallel-path oxidation. However, independent measurements of CO electro-oxidation, CO thermal desorption, and parallel-path oxidation are required to elucidate the respective role of these processes in elevated temperature methanol electro-oxidation. Results of such measurements will be presented for supported Pt catalysts using the DEFC technique augmented with pulsed reactant injection. @FootnoteText@ @footnote 1@ T.H. Madden and E.M. Stuve, submitted to J. Electrochem. Soc. (2001).