Na_2WO_4-Mn/mullite Catalysts for Oxidative Coupling of Methane

摘要

The catalysts, 5 wt% Na_2WO_4 -2 wt% Mn on mullites sintered at 1200°C, 1300°C, 1400°C, and 1500°C, were prepared by incipient wetness impregnation method for the oxidative coupling of methane (OCM) reaction in a fixed-bed quartz tube reactor. These catalysts were characterized by XRD, XPS and BET method. The XRD pattern of Na_2WO_4-Mn/mullite indicated that the main crystal phase of metal oxide was MnWO_4. From the XPS spectra, the results revealed the information on Na, W and Mn species distributed on the catalyst surface. For catalytic activity testing, Na_2WO_4-Mn/mullite sintered at 1300°C showed the highest C_2 selectivity of 11.4% and Na_2WO_4-Mn/mullite sintered at 1400°C showed the highest CH_4 conversion of 56.6%.