Abstract Mn-M-O (M=Cu or Co) composite metal oxides were prepared by a co-precipitation method and their abilities concerning the NOx storage capacity (NSC) in lean burn atmospheres and NOx storage reduction (NSR) in the periodically alternative lean burn/fuel rich atmospheres were investigated. The results indicated that the Mn-O sample showed good catalytic activity: the NO-to-NO2 conversion was 83.4%, and the NSC was 124.2 μmol/g. However, it had the drawback of the poor reduction activity in the fuel rich atmospheres. The doping with the Cu or Co element can remarkably decrease the mean crystallite sizes, increase the thermal aging resistance, and consequently enlarge the specific surface areas of the catalysts. This induced the enhancement of the NO storage capacity and the NO reduction ability at low temperatures. The H2-TPR results demonstrate that doping with Cu or Co element can result in the shift of the reduction peak of the H2-TPR profiles toward lower temperature. It indicated an increase in the oxygen activity, which further improved the redox ability of the doped Mn based oxides. The Mn-Cu-O sample displayed the best NSR activity due to its good NO reduction activity in the fuel-rich atmospheres.
LI Xin-Gang, GUO Li, XIAN Hui.Cu, Co Doped Manganese Composite Metal Oxides for NOx Storage and Reduction at Low Temperatures[J] Chemcial Industry and Engineering, 2014,V31(4): 1-5
2014, Vol. 31 
