Oxygen X-ray absorption near-edge structure characterization of the Ba-doped yttria oxidative coupling catalyst

Abstract Ba-doped Y 2 O 3 is one of the most active catalysts for the oxidative coupling of methane. Here, based on measurements of the oxygen K-edge X-ray absorption edge, X-ray diffraction, X-ray fluorescence, and X-ray photoelectron spectroscopy and its catalytic activity and selectivity, we propose that the active sites are charge-deficient oxygen sites created as Bat+ substitutes into Y 3+ lattice sites. The substitution is temperature dependent, becoming significant only at higher temperatures. We have found a correlation of catalytic activity and selectivity as a function of Ba loading on Y203. This is reflected in the oxygen K-edge absorption near the absorption edge.