Showing papers by "Zongping Shao published in 1998"

New methods to prepare perovskite-type La0.8Sr0.2CoO3 catalyst at low temperature

Abstract: A pure phase perovskite-type composite oxide La0.8Sr0.2CoO3 (LSCO) was prepared by three methods: sol-gel method using EDTA as ligand, environmentaly safe metal-EDTA-cellulose complexing method and metal-citric-cellulose complexing method. The formation processes of LSCO by those methods were investigated by TG-DTA, XRD and IR spectroscopy. The results indicated that when EDTA complexing method was used, at optimized condition, pure phase perovskite-type LSCO was acquired after the precursor was fired at 800 degrees C for 2hr. In the process of forming perovskite LSCO, SrCO3 was formed and calcination temperatures higher than 800 degrees C was needed to get rid of it, similar to the citric complexing method reported. When cellulose was introduced, the minimum calcination temperature to acquire pure phase LSCO was significantly lowered to around 600 degrees C for metal-EDTA-cellulose method and 540 degrees C for metal-citric-cellulose method. Low calcination temperature led to relatively high BET area for 21m(2)/g and 22m(2)/g respectively. But the surface area were significantly reduced to 12.7m(2)/g and 12.1m(2)/g respectively when they were further fired at 620 degrees C for 2hr.