Kinetic study of the partial oxidation of methane over Fe2(MoO4)3 catalyst

Abstract

The product distributions for partial oxidation of methane over Fe₂(MoO₄)₃ catalyst are compared with those for partial oxidation of methanol in the presence and absence of methane over the same catalyst under similar reaction conditions. The results suggest that CH₃OH is the precursor of HCHO which is the main product of partial oxidation of methane by oxygen over Fe₂(MoO₄)₃. The consecutive oxidation of HCHO leads to the formation of CO, the main by-product, and CO₂. The presence of abundant methane improves the selectivity to HCHO.

The results of kinetic studies on methane oxidation are analysed in terms of the Eley–Rideal model in which the rate-determining step is the activation of methane by the dissociatively adsorbed oxygen. The absence of C₂ hydrocarbons in the products suggests that the reaction intermediate is either the surface CH₃ species or the methoxide, formed from the reaction of CH₄ with the adsorbed oxygen. The mechanism for the formation of HCHO and CO is also discussed on the basis of the results of partial oxidation of methane and methanol.