FROM CH4 REFORMING WITH CO2 TO PYROLYSIS OVER A PLATINUM CATALYST

At temperatures up to 1100-degrees-C, CH4 and CO2 react over a Pt wire to give mainly the reforming product CO, even at a CH4/CO2 ratio of 4 .3. But if coke is present on the wire, the dominant reaction becomes the pyrolysis of CH4 to form mainly C2H2 and C6H6. Thus, surface carbo n poisons the reforming reaction and is autocatalytic for CH4 pyrolysi s. Higher temperatures and larger CH4/O2 ratios favor the formation of coke and the pyrolysis reaction. Molecular oxygen and, to a lesser ex tent, water have the opposite effect.