A Study of the Mechanism of the Partial Oxidation of Methane over Rare Earth Oxide Catalysts Using Isotope Transient Techniques

Article abstract of DOI:10.1021/j100350a039

The mechanism of the partial oxidation reaction of methane over three catalysts (Sm2O3, Li/Sm2O3, and Pr6O11) having a range of activities and product selectivities has been studied by using isotope transient techniques.The most important conclusions from this study are (1) that large amounts of CH4 are adsorbed on all working catalysts, (2) that the reaction takes place on a small number of very active catalyst sites and does not involve the adsorbed CH4, (3) that gas-phase oxygen exchanges rapidly with the lattice oxygen atoms of the working catalysts, (4) that the rate of CH4 conversion is dependent on the rate of lattice oxygen exchange, and (5) that the carbon oxides are substantially formed by the secondary oxidation of the reaction products.A mechanism based on the formation and reactions of -> species is proposed for the C₂₊ products, but a different form of activated oxygen appears to be responsible for the formation of the carbon oxides.