Influence of Composition of Perovskite-type Catalysts La_(1-x)A_xB_yMn_(1-y)O_3 on Simultaneous Removal of NO_x and Soot

Using temperature programmed reaction (TPR) method, catalytic removal of nitrogen oxides (NOx) and soot with modeled diesel engine exhaust was studied to investigate the effects of different catalysts. The catalysts used in this study are based on perovskite-type oxides LaMnO3. By substituting parts of La and Mn with other cations, La1-xAxByMn1-yO3 (A and B are dopants) were obtained and the catalytic activities of these catalysts were systematically studied. The results indicate that both the selectivity and the activity of catalysts can be improved by doping appropriate cations. By substituting suitable amount of La with Ce or K, the performances of catalysts can be improved. Substituting parts of Mn with Cu at the same time, the performances of catalysts can be improved furthermore. The results show that the comprehensive performance of La0.8K0.2Cu0.05Mn0.95O3 is better than others. When using it as catalyst, the maximum NO conversion into N2 and the ignition temperature of soot are 66.0% and 290℃ respectively. All these prove that this catalyst is a promising one for simultaneous removal of NOx and soot.