Non-thermal plasma enhanced NSR performance over Pt/M/Ba/Al2O3 (M=Mn, Co, Cu) catalysts

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 314; no. C; pp. 688 - 699
• Main Authors: Bai, Zhifeng, Zhang, Zhaoshun, Chen, Bingbing, Zhao, Qi, Crocker, Mark, Shi, Chuan
• Format: Journal Article
• Language: English
• Published: Switzerland Elsevier B.V 15.04.2017; Elsevier
• Subjects: Non-thermal plasma; NOx storage-reduction; Transition metal oxide; Transition metal oxide; Non-thermal plasma; NOx storage-reduction
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2016.12.034

[Display omitted] •Doping redox active transition metal oxides into LNT catalysts improved NOx storage capacity.•Employing H2-plasma in rich phase assisted reduction of the stored NOx.•High NOx conversion can be obtained over a broad temperature range (150–350°C). To improve the NOx storage capacity (NSC) of lean NOx trap (LNT) catalysts of the Pt/BaO/Al2O3 type, the catalyst was doped with redox active transition metals of Mn, Co, or Cu, respectively. Due to differences in the chemical states of the doped metals, the catalysts exhibited different catalytic behaviors. Co and Mn doped catalysts showed improved NO to NO2 oxidation ability, and therefore enhanced NOx storage capacities, which led to the increased cycle averaged NOx conversions as compared to a Pt/Ba/Al2O3 reference. However, being limited by NOx reduction in rich phase, the NOx conversions were still poor at low temperatures (<250°C). By employing an H2-plasma in rich phase to assist NOx reduction, NOx conversions were greatly enhanced especially for low temperatures (⩽250°C). The best properties were achieved over Pt/Co/Ba/Al2O3 catalyst which exhibited NOx conversions higher than 80% in the whole temperature range (150–350°C) and best SO2 resistance abilities.