Catalysts of Co,K/La 2 O 3 have been prepared by wet impregnation. The samples have been calcined at 400• C and 700 • C and have been characterized for phase composition using x-ray diffraction and Fourier transform infrared spectroscopy. The XPS analysis of the samples has been obtained by examination of the O 1s, K 2p, C 1s and La 3d spectral regions. The XPS data are discussed with respect to the calcination temperatures and the soot combustion performed in the spectrometer reaction chamber. Analysis of the XPS data indicates considerable carbonation of the surfaces of all samples, even after burning the soot. The K/La 2 O 3 solid presents the highest content of surface carbonated species, showing the highest catalytic activity for soot combustion. Interaction of the catalysts with CO 2 is studied by temperatureprogrammed desorption and microbalance experiments. Kinetic studies and surface characterization of the potassium-containing samples suggest that an appropriate surface potassium concentration is necessary for a synergetic action between potassium and lanthanum. In the cobalt-containing catalysts calcined at 700• C, an increase is observed in the concentration of the outer-layer perovskite species when the potassium content increases, following the same tendency observed in the bulk. Such LaCoO 3 species would limit the reaction of lanthanum with CO 2 .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.