LaCo1−x Pd x O3 Perovskite-Type Oxides: Synthesis, Characterization and Simultaneous Removal of NO x and Diesel Soot

Abstract

A series of naometric perovskite catalysts LaCo1−x Pd x O3 (x = 0, 0.01, 0.03) were prepared via a solution combustion synthesis route using metal nitrates as oxidizers and urea as fuel. It is essential to add a certain amount of ammonia aqueous solution to Pd2+ ions solution in the catalyst preparation process. Homogeneous nanoparticles LaCo1−x Pd x O3 catalysts with the sizes in the range of 68–122 nm were obtained and characterized by using of XRD, BET, H2-TPR, XPS, SEM and TEM. Pd was successfully introduced into the LaCoO3 perovskite lattices. Further information was obtained by using XPS upon the LaCo0.97Pd0.03O3 (with NH4OH) sample after H2-TPR. The results revealed that surface Pd was reduced to the metallic state at the end of the first step in the H2-TPR experiment, and some surface Co could be reduced to metallic Co simultaneously. The catalytic properties were investigated for simultaneous NO x -soot removal reaction. The performance of LaCo1−x Pd x O3 catalysts were greatly improved by the partial substitution of Pd. The maximum NO conversion into N2 and the ignition temperature of soot are 32.8% and 265 °C, respectively.