REACTIVITY OF PEROVSKITES ON OXIDATIVE COUPLING OF METHANE

Well-defined structures like ABO(3) (A = Ba, Sr, Ca; and B = Ti, Zr) p erovskites were prepared by a sol-gel method which permits the formati on of a crystalline structure at low-calcination temperatures (similar to 700 degrees C). The perovskite structures were characterized by X- ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer -Emmett-Teller (BET) methods and the carbonate present at the surface was determined by Fourier transform infra-red spectroscopy. Reactivity studies showed that the perovskite structures are stable under oxidat ive coupling of methane (OCM) conditions. The yield increases followed the sequence Ca < Sr < Ba and Zr < Ti, and a stable BaTiO3 gives a C- 2 yield of 15% at 800 degrees C.