Non-thermal plasma-assisted NOx storage and reduction on a LaMn0.9Fe0.1O3 perovskite catalyst

Based on its high NOx storage capacity (NSC), a study of the properties of LaMn0.9Fe0.1O3 in NOx storage-reduction catalysis was undertaken. The microstructure of the LaMn0.9Fe0.1O3 catalyst was characterized by XRD, XPS and H2-TPR techniques and compared with that of LaMnO3. The role of Fe doping in LaMnO3 on the perovskite structure and on NOx storage capacity was clarified. Though the LaMn0.9Fe0.1O3 perovskite has high NSC values even at relatively low temperature (<300 °C), it shows much lower activity during lean-rich cycling compared with a traditional Pt/BaO/Al2O3 catalyst, indicating that regeneration of stored NOx is the rate limiting step for the perovskite catalyst. By employing an H2-plasma in the rich phase to assist reduction of the stored NOx, the NOx conversion is greatly improved, especially at low temperature. The results of the present study show that by combining the high NOx storage capacity of the perovskite in the lean phase with non-thermal plasma-assisted activation of the reductant in the rich phase, high NOx conversion can be obtained at low temperature.