A novel CeO_2 supported Ba_(0.3)Sr_(0.7)Co_xFe_(1-x)O_(3-δ) perovskite for chemical looping steam methane reforming to syngas and hydrogen

摘要

CeO_2 supported Ba_(0.3)Sr_(0.7)Co_xFe_(1-x)O_(3-δ) (x=0.9, 0.8, 0.5) perovskite-type oxides were synthesized using a sol-gel method and used as oxygen carrier for chemical-looping steam methane reforming (CL-SMR). The as-prepared samples were characterized by X-ray diffraction (XRD), and their performance in CL-SMR was evaluated in a fixed-bed reactor. The results suggested that perovskite-type crystallites of Ba_(0.3)Sr_(0.7)Co_xFe_(1-x)O_(3-δ) were formed during preparation, and some of CeO_2 could supply oxygen to perovskite during partial oxidation of methane. Metal ions in B-site, Co and Fe, which were formed during methane reaction, could in turn react with water to generate hydrogen. Further results on H_2/CO production kinetics showed that the optimal reaction temperature was about 860°C, and the proper reaction time in fuel reactor was about 180s when weight hourly space velocity (WHSV) was 23.5 h~(-1).