Perovskite catalysts for oxidative coupling of methane improved by Y-doping

Oxidative coupling of methane (OCM) is an effective route for methane direct conversion to ethylene. Perovskite oxides (ABO 3 ) with variable properties are potential catalysts for OCM by adjusting the compositions. In this study, four perovskite catalysts, BaMO 3-δ and BaM 1-x Y x O 3-δ (M = Zr, Ce; x = 0.2), were prepared by the sol–gel method to explore their catalytic performance of OCM. All catalysts are active toward OCM and reach the highest catalytic performance at 800°C. The OCM performance of Ce-based catalysts is higher than that of Zr-based catalysts. The selectivity of C 2 compounds is significantly improved by Y-doping. At CH 4 /O 2 mol ratio of 8, a C 2 selectivity of 67% was achieved on BaCe 0.8 Y 0.2 O 3-δ . Compared with Zr-based catalysts, more amounts of active oxygen species, which are beneficial to OCM, were observed on BaCeO 3-δ and BaCe 0.8 Y 0.2 O 3-δ . Meanwhile, higher contents of moderate and strong basic sites, which are beneficial to OCM, were found on the Y-doped catalysts. This is attributed to the generation of oxygen vacancies caused by Y-doping in the B-site. Therefore, BaCe 0.8 Y 0.2 O 3-δ with more active oxygen species and stronger basicity exhibits the highest performance among the four catalysts.