Preparation and characterization of Pd loaded Sr-deficient K2NiF4-type (La, Sr)(2)MnO4 catalysts for NO-CO reaction

Pdloaded K2NiF4-type perovskite oxides, Pd/La0.2Sr1.8-xMnO(4) were prepared by liquid-phase adsorption process, and their structural and catalytic properties were investigated. Pd deposition was carried out by mixing La0.2Sr1.8MnO4 with Pd(NO3)(2) in aqueous solution, followed by filtration, drying, and calcination at 800 degrees C. During the Pd deposition process, 5% of Sr in La0.2Sr1.8MnO4 oxides was dissolved into the aqueous phase, whereas the perovskite structure retained. The content of Pd loaded on La0.2Sr1.8MnO4 was 0.24 wt%. X-ray absorption spectroscopy studies showed that highly dispersed PdO nanoparticles were supported on Pd/La0.2Sr1.8MnO4 prepared by the liquid-phase adsorption process, whereas aggregated PdO particles were formed on Pd/La0.2Sr1.8MnO4 prepared by an impregnation method. The Pd/La0.2Sr1.8MnO4 catalyst prepared by the liquid-phase adsorption process exhibited higher catalyticactivity for NO-CO reaction than the 0.24 wt% Pd/La0.2Sr1.8MnO4 catalyst prepared by the impregnation method. (C) 2014 Elsevier B.V. All rights reserved.