The critical role of the surface WO4 tetrahedron on the performance of Na-W-Mn/SiO2 catalysts for the oxidative coupling of methane

Abstract A series of M-W-Mn/SiO2 catalysts (M- Li, Na, K, Ba, Ca, Fe, Co, Ni, and A1) have been prepared and their catalytic performances for OCM were evaluated. The roles of the WO 4 tetrahedra and the WO 6 octahedra on the catalyst surface have been investigated using X-ray photoelectron spectroscopy (XPS) and laser Raman spectroscopy (LRS).