Nature of the perovskites surface centers as studied by the Infrared spectroscopy of adsorbed NO test molecule

FTIR spectroscopy of adsorbed NO revealed a variety of types of coordinativ ely unsaturated surface cations for lanthanum cobaltites, manganites, and f errites, some of which emerge due to room-temperature surface reduction by the test molecule. For the surface of LaFeO3, clusters of coordinatively un saturated Fe2+ cations associated with surface defects dominate. For the su rface of LaCoO3 and LaMnO3, coordinatively unsaturated Me+3 cations are mai nly revealed, being more coordinated by oxygen for the former system. These results could be used to analyze the catalytic properties of perovskites i n the reaction of CO oxidation, provided the density of surface sites and r eaction mechanism are taken into account. (C) 2000 Elsevier Science B.V. Al l rights reserved.