Preparation and High-Temperature Water-Gas Shift Catalytic Features of La_(1-x)Ce_xFeO_3 Perovskite

摘要

Based on water-gas shift reaction mechanism and perovskite compounds characteristics, La_(1-x)Ce_xFeO_3 (.K) perovskite were designed and prepared as shift catalysts. DTA and XRD results reveal that La_(1-x)Ce_xFeO_3 can be formed at 730 approx 760 deg C by mechanic-mix thermal decomposition method. Activity and heat-resisting tests show that La_(1-x)Ce_xFeO_3 (.K) possess high thermal stability if x is less than or equals to 0.5. But when x is greater than 0.5, La_(1-x)Ce_xFeO_3 (.K) will be converted into ceria and magnetite partially or completely under shift reaction conditions. In the case of x = 0.5, the conversion of CO is about 68 percent at 530 deg C. Potassium can greatly improve the low temperature activity, but slightly reduces the high temperature activity, and has little impact on the thermal stability. La_(0.5)Ce_(0.5)FeO_3 (.K) is a promising chromium-free high temperature shift catalyst.