Hybrid catalysts containing Ba, Ti, Mn, Na, and W for the low-temperature oxidative coupling of methane.

[Display omitted] • Na-W-Mn-Ba-Ti composite catalyst exhibited 26.0 % C 2+ yield at 700 °C. • Optimum temperature, 700 °C, is 100 °C lower than that of conventional Mn-Na 2 WO 4. • Nanostructures of catalyst adjusted the redox of Mn and W. • H 2 -TPR, TEM, XRD, Raman, and others elucidated the catalytic activity. The oxidative coupling of methane (OCM) using hybrid catalysts containing BaTiO 3 perovskite and Mn-Na 2 WO 4 exhibited high activity and high selectivity at low temperature: 66.3 % C 2+ (olefins and paraffins) selectivity and 25.9 % C 2+ yield at 700 °C which is 100 °C lower than that used for Mn-Na 2 WO 4 catalysts (800 °C). Upon the preparation of complex catalysts, the insertion of Mn into BaTiO 3 (BaTi(Mn)O 3) and the formation of Na x Mn(Ti)O 2 improved the oxygen-supplying ability of the catalysts. Additionally, strong interactions between the WO 4 2− anions and BaTi(Mn)O 3 or Na x Mn(Ti)O 2 stabilized the WO 4 2− anions on the surface and improved the methane activation ability of the catalysts for the favorable production of hydrocarbons. The nanoscopic modification of catalysts was confirmed using H 2 –temperature-programmed reduction, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy results. [ABSTRACT FROM AUTHOR]