Synthesis of LaKMnO perovskite-type oxides and their catalytic property for simultaneous removal of NOx and diesel soot particulates

Mixed metal oxides in the LaKMnO system were synthesized and their catalytic properties toward the simultaneous NOx–soot removal reaction were investigated. The solubility limit of K in La1−xKxMnO3 was determined between 0.2 and 0.25 from X-ray diffraction (XRD) measurement and crystal structure investigation, and K2Mn4O8 was by-produced beyond the solubility limit. The activity and the NOx reduction selectivity depended significantly on the K content, and the oxides with intermediate K contents (x=0.2 and x=0.25) or with the composition close to the solubility limit were good catalysts with higher activity and selectivity. The present study revealed that the LaKMnO oxides are good candidates of catalysts for the simultaneous NOx–soot removal reaction.