Probing Low-Temperature OCM Performance over a Dual-Domain Catalyst Bed

Abstract

The Mn-Na2WO4/SiO2 catalyst is regarded as the most promising catalyst for the oxidative coupling of methane (OCM). Despite its remarkable performance, the Mn-Na2WO4/SiO2 catalyst requires a high reaction temperature (>750 °C) to show significant activity, a temperature regime that simultaneously causes quick deactivation. In the current work, we show that the benefits of this catalyst can be leveraged even at lower reaction temperatures by a using a stacked catalyst bed, which includes also a small amount of 5% La2O3/MgO on-top- of the Mn-Na2WO4/SiO2 catalyst. The simple stacking of the two catalysts provides >7-fold higher activity and ~1.4-fold higher C2 yield at 705 °C compared to Mn-Na2WO4/SiO2 and La2O3/MgO, respectively. We specifically show that the enhanced OCM performance is associated with synergistic interactions between the two catalyst domains and study their origin.