Catalytic properties of yttria doped bismuth oxide ceramics for oxidative coupling of methane

Abstract

Fluorite structured bismuth oxide-based ceramics are potential membrane materials for oxygen separation and membrane reactor applications. In this work, the catalytic properties of the surface of several bismuth oxide-based ceramics for oxidative coupling of methane were studied using a conventional tubular reactor operated in the cofeed mode. A most commonly studied catalyst, 5 wt% Li/MgO ( Li/MgO), was selected as a reference catalyst. 30 mol% Y 2O 3 doped Bi 2O 3 (BY30) exhibits C 2 yield (18%) and selectivity (50%) similar to Li/MgO at 800–850°C, but the former has a C 2 space-time yield 15 times higher than the latter. Like Li/MgO, BY30 also yields more C 2H 4 and CO 2 than C 2H 6 and CO in its products. The comparison studies on Bi 2O 3, BY25, BY30 and Y 2O 3 show that doping yttria in Bi 2O 3 results in an increased C 2 yield and a slightly decreased C 2 selectivity. A decrease in the surface area of the bismuth oxide-based ceramics gives a larger C 2 selectivity and a lower C 2 yield.