Preparation and Calcination Temperature Optimization of La1-xSrxCo1-yFeyO3 for Removing NOx Effectively
The automotive emission has become the main source of the air pollution in cities. How to remove NOx effectively is the key and difficult point in the control of automobile exhaust. In this work, sol-gel was applied to prepare NOx purification catalyst, LaCoO3 which was doped with strontium (Sr) and iron (Fe). The average particle size was less than 25 nm. The optimum composition of doped LaCoO3 was determined as La0.8Sr0.2Co0.95Fe0.05O3 with a minimum particle size, 14.3nm. The denitrification rate of La0.8Sr0.2Co0.95Fe0.05O3 increased by 27.9% compared with that of LaCoO3. It was noted that the sample powder would agglomerate when doped LaCoO3 was calcinated at 800°C, the calcination temperature of LaCoO3. Therefore the calcination temperature for double doped LaCoO3 was optimized. According to results of XRD and BET, the optimum calcination temperature of La0.8Sr0.2Co0.95Fe0.05O3 is 575°C, which not only overcame the agglomeration but also reduced the particle size to 11.2nm. The denitrification rate of La0.8Sr0.2Co0.95Fe0.05O3 calcinated at 575°C is up to 95.8% which is higher 38.7% than that of it calcinated at 800 °C.