Industrially Produced Fe- And Mn-Based Perovskites: Effect of Synthesis on Reactivity in Three-Way Catalysis: Part 1 ()

Abstract

La0.6Ca0.2Fe0.8Cu0.2O3, undoped (LF) and Ca, Cu-doped (LCFC), powders, obtained by different industrial procedures, are compared to evaluate reproducibility and scale-up in different industrial synthetic approaches: flame spray pyrolysis (FSP) and coprecipitation (COP). Also the effects of varying composition (doping) and FSP process variability are considered as comparative studies on morphological, crystallographic, redox and compositional properties, and functional activity. A model reaction (CO + NO) and reactions with an automotive exhaust mixture were carried out. Unexpected results on the effectiveness of doping for catalytic activity emerged. Samples with the same compositions proved to be significantly affected by the synthesis, with variability within the same process. The activity of LCFC COP is comparable to the FSP analogue, at stoichiometric conditions, notwithstanding differences highlighted by characterization. In an oxygen-deficient mixture, LCFC-COP yields higher NO reduction and CO oxidation activity than LCFC-FSP. The absence of Ca in the lattice was unexpectedly beneficial. The doping effectiveness must be carefully checked for large-scale production.