Effect of A-site deficiency in LaMn0.9Co0.1O3 perovskites on their catalytic performance for soot combustion

DINAMARCA, R., GARCIA, X., JIMENEZ, R., FIERRO, J.L.G., PECCHI, G.:
Materials Research Bulletin, 81, 134-141 (2016).

DOI: 10.1016/j.materresbull.2016.05.007

Abstract

The influence of lanthanum stoichiometry in Ag-doped (La1-xAgxMn0.9Co0.1O3) and A-site deficient (La1-xMn0.9Co0.1O3-δ) perovskites with x equal to 10, 20 and 30 at.% has been investigated in catalysts for soot combustion. The catalysts were prepared by the amorphous citrate method and characterized by XRD, nitrogen adsorption, XPS, O2-TPD and TPR. The formation of a rhombohedral excess-oxygen perovskite for Ag-doped and a cubic perovskite structure for an A-site deficient series is confirmed. The efficient catalytic performance of the larger Ag-doped perovskite structure is attributed to the rhombohedral crystalline structure, Ag2O segregated phases and the redox pair Mn4+/Mn3+. A poor catalytic activity for soot combustion was observed with A-site deficient perovskites, despite the increase in the redox pair Mn4+/Mn3+, which is attributed to the cubic crystalline structure.

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