Support effect on the chemical properties of Mn2O3/Na2WO4/MOx catalysts in the oxidative coupling of methane

The high stability and excellent performance of NaWMn based catalysts in the oxidative coupling of methane (OCM) are expected to promote their industrial application. However, the selection of supports has significant impact on the OCM performance of NaWMn-based catalysts. In this work, we found that the addition of Na₂WO₄/MO_x to Mn₂O₃ can change the function of the Mn₂O₃ catalyst from methane combustion to oxidative coupling of methane, and the Mn₂O₃/NaWSi catalyst exhibits the highest performance. The isotope oxygen exchange and CH₄-TPSR results confirm that the appropriate oxygen exchange rate is beneficial for improving the catalytic performance of OCM reaction. H₂-TPR and O₂-TPD results demonstrate that the Mn₂O₃/NaWSi catalyst has moderate redox ability and can slowly release oxygen species at lower temperatures, matching the rate of methane consumption with the rate of C₂ generation.