Exploring the effect of using carbon black in the sol-gel synthesis of BaMnO3 and BaMn0.7Cu0.3O3 perovskite catalysts for CO oxidation

Abstract

BaMnO3 and copper-doped BaMnO3 perovskites seem to be a feasible alternative to current catalysts for the exhaust treatment. In this work, these formulations have been synthesized by a modified sol-gel method in which carbon black has been added to the conventional sol-gel process in order to improve the physical and chemical properties that modulate the catalytic performance. The samples have been deeply characterized by ICP-OES, XRD, XPS, H2-TPR and O2-TPD. The characterization results point out that the use of carbon black allows decreasing the calcination temperature which minimizes the sintering effects and improves the textural properties, the reducibility, and the oxygen mobility. The study of CO oxidation, using different simulated atmospheres, reveals that all the catalysts were active for CO to CO2 oxidation, but only when oxygen is supplied in excess, an effect of the synthesis method is observed. Additionally, as expected, the presence of copper (inserted or not into the perovskite lattice) benefits the catalytic performance. Otherwise, it seems that the catalytic performance for CO oxidation of BaMnO3-based samples is less affected by the fluctuations of CO and O2 concentrations than the platinum-based catalyst used as reference.