Eliminación simultánea de hollín y NOx. Preparación y evaluación de catalizadores Pt,Rh,K/La2O3

BÁRBARA S. SÁNCHEZ*, CARLOS A. QUERINI, EDUARDO E. MIRÓ

La Plata- Argentina

Congreso; XV Congreso Argentino de Catálisis y 4° Congreso de Catálisis del MERCOSUR; 2007

CONACA

The main contaminants present in diesel exhaust gases are soot particles and nitrogen oxides. In our group it has been proved that the K/La2O3 catalyst is very active for soot combustion. In this work we prepared lanthanum supported catalysts that, besides potassium, contained platinum and rhodium, to determine their activity for the simultaneous elimination of soot and NOx. The catalysts were characterized by temperature programmed reduction. In order to evaluate the degree of interaction between the metals and the lanthanum oxide support, we prepared catalysts with identical composition, but supported on ceria. We also prepared catalysts with different compositions and different impregnation methods, which allowed us to determine how these variables influence the TPR profiles. Isothermic experiencies were carried out at different temperatures, using different configurations, in NO + O2 atmosphere, in order to find out the better conditions to evaluate the activity of the prepared catalysts. It was found that this activity significantly changes with the preparation method, as well as the catalyst composition. It was possible to eliminate an important fraction of soot using a Pt,Rh,K/La2O3 catalyst at 300 °C in the presence of 0.1% NO