Production of Synthesis Gas by Direct Catalytic Oxidation of Methane on Pt{110} (1 × 2) Using Supersonic Molecular Beams

The absolute rate of the methane oxidation reaction over Pt{110} was investigated over the temperature range 400−900 K using molecular beams under ultrahigh vacuum (UHV) conditions. It was found that the surface reaction is biphasic, with CO 2 being the major product at <550 K and CO the major product at >600 K. Under our reaction conditions, the reaction products H 2, CO, and CO 2 were detected. The H 2 O production was below the limit of detectability. The product selectivity to CO and CO 2 can be controlled by varying the beam composition as well as the surface temperature. A mean field coupled differential equation model of the process provides a reasonable description of all the experimental observations, although it does not include a proper description of prompt CO desorption at high surface temperatures.