MECHANISTIC INVESTIGATION ON THE La2O3- CATALYZED OXIDATIVE COUPLING OF METHANE REACTION

摘要

Oxidative coupling of methane (OCM) is a promising route for the efficient conversion of methane into ethylene, and La2O3-based catalysts have been shown to have good catalytic activity, selectivity and stability. Despite the numerous experimental and computational studies on this reaction over the past three decades, there remain debates on the nature of the active sites and the detailed catalytic mechanism for this reaction. We have used both cluster and surface models to study the activation and conversion of methane on the La2O3 catalysts. In this contribution, we examined the reactivity of the different oxygen species with methane, and built a comprehensive reaction network for the OCM reaction. In addition, we also investigated the effects of the acid-base properties on the catalytic activity. Reactivities of the different La2O3 surfaces were also studied.