Structuration of LaMnO3 perovskite catalysts on ceramic and metallic monoliths: Physico-chemical characterisation and catalytic activity in methane combustion

摘要

LaMnO3 perovskite was prepared by the citrate method and deposited on ceramic and metallic monoliths according to a dip coating or an orbital stirring procedure. Both types of structured catalysts were characterised by specific surface area measurements (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The parameters influencing the amount of deposited catalyst, such as the nature of the monolith and the coating technique, were investigated. Comparisons between structured and powdered catalysts showed a higher catalytic activity of the former. A better behaviour of structured LaMnO3 on metallic monoliths was observed at a lower temperature, and higher catalytic activities were observed for structured LaMnO3 on ceramic monoliths at a higher temperature. The influence of a diffusion limitation of the reaction rate in structured catalysts was observed.