CATALYTIC REACTION OF METHANE WITH CARBON-DIOXIDE OVER SUPPORTED PALLADIUM

The reforming of methane with carbon dioxide has been investigated at 673-773 K on supported palladium catalysts in a fixed-bed continuous-flow reactor. In addition, the dissociation of carbon dioxide and methane, and the reactivity of die surface carbon formed have also been examined. The dissociation of carbon dioxide, detected by infrared spectroscopy, occurred at the lowest temperature, 373 K, on Pd/TiO2. It was greatly promoted by the presence of methane. The decomposition of methane at the temperature of the CH4 + CO2 reaction (ca. 773 K) proceeded initially at a high rate yielding hydrogen and small amounts of ethane and ethene. The deposition of surface carbon was also observed, which was hydrogenated only above 720 K. The reaction between carbon dioxide and methane occurred rapidly above 673 K to give carbon monoxide and hydrogen with a ratio of 1.3-1.7. Very little carbon was deposited during the reaction of a stoichiometric gas mixture. Kinetic parameters of the reaction were determined and a possible reaction mechanism is proposed.