Catalytic Characteristics of Perovskite-type Oxides under Mixed Methane and Oxygen Gases

As the single chamber SOFC (SC-SOFC) showed higher prospect on reducing the operation temperature as well as offering higher design flexibility of SOFCs, lots of concerns have been given to investigate the catalytic activity of perovskite- type oxide in mixed fuel and oxidant conditions. Hence we thoroughly investigated the catalytic property of various perovskite- type oxides such as La0.8Sr0.2MnO3(LSM), La0.6Sr0.4CoO3 (LSC), La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), Sm0.5Sr0.5CoO3 (SSC), and Ba0.5Sr0.4Co0.8Fe0.2 (BSCF) under the partial oxidation condition of methane which used to be given for SC-SOFC operation. In this study, powder form of each perovskite oxides whose surface areas were controlled to be equal, were investigated as functions of methane to oxygen ratios and reactor temperature. XRD, BET and SEM were employed to characterize the crystalline phase, surface area and microstructure of prepared powders before and after the catalytic oxidation. According to the gas phase analysis with flow-through type reactor and gas chromatography system, LSC, SSC, and LSCF showed higher catalytic activity at fairly lower temperature around 400 degrees C similar to 450 degrees C whereas LSM and BSCF could be activated at much higher temperature above 600 degrees C.