Pd-integrated perovskites for TWC applications: Synthesis, microstructure and N2O-selectivity

Abstract

Two versions of Pd-doped perovskite based catalysts (Pd impregnated onto or integrated into perovskite: Pd-LaFe0.65Co0.35O3 and LaFe0.65Co0.3Pd0.05O3) were synthesized by applying a modified citrate route and analyzed by XRD, TEM and XPS. The catalytic properties of the perovskites were measured for NO reduction reactions occurring in three way catalysis, including lean, stoichiometric and rich conditions. The N2O concentrations were measured and compared to the N2O formation of a commercial three way catalyst. The perovskite-based catalysts produced significantly less N2O than the TWC – ca. 75 % under lean conditions at the temperatures of maximum N2O-formation and ca. 60 % less N2O under stoichiometric conditions. Under rich conditions the Pd-LaFe0.65Co0.35O3 catalyst produced ca. 58 % less N2O than the TWC, while no N2O was detected at all on the Pd-integrated perovskite LaFe0.65Co0.3Pd0.05O3 under these conditions.