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

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% Y2O3 doped Bi2O3 (BY30) exhibits C2 yield (18%) and selectivity (50%) similar to Li/MgO at 800–850°C, but the former has a C2 space-time yield 15 times higher than the latter. Like Li/MgO, BY30 also yields more C2H4 and CO2 than C2H6 and CO in its products. The comparison studies on Bi2O3, BY25, BY30 and Y2O3 show that doping yttria in Bi2O3 results in an increased C2 yield and a slightly decreased C2 selectivity. A decrease in the surface area of the bismuth oxide-based ceramics gives a larger C2 selectivity and a lower C2 yield.