From CH₄ reforming with CO₂ to pyrolysis over a platinum catalyst

Abstract

At temperatures up to 1100°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 carbon poisons the reforming reaction and is autocatalytic for CH₄ pyrolysis. Higher temperatures and larger CH₄/O₂ ratios favor the formation of coke and the pyrolysis reaction. Molecular oxygen and, to a lesser extent, water have the opposite effect.