Optimized preparation of washcoated clay honeycomb monoliths as support of manganese catalysts for acetone total combustion

Abstract

Abstract Clay honeycomb monoliths (MC) washcoated by pillared clay (PILC) obtained from the same starting material were used as support of manganese catalysts for the complete oxidation of acetone. Using the same clay for extrusion and pillaring processes intended to optimize the catalyst preparation respect to previous similar studies through raw materials saving, with subsequent local clay valorization, and washcoat adherence enhancement due to higher chemical affinity with the monolith substrate. To evaluate the influence of the PILC presence on the catalytic behaviour, two other non-coated monolith catalysts were prepared as references, having different loads of manganese as function of the impregnation cycles number applied, either one (Mn/MC) or two (Mn2/MC). All the catalysts were characterized by TGA, XRD, XRF, N2 physisorption and SEM. The catalytic tests used acetone as a VOC model molecule. The results indicated that the PILC coating (Mn/PILC/MC) led to a higher percentage of Mn2O3 (7 wt%) compared to Mn/MC (1 wt%). Moreover, the PILC-washcoated sample exhibited better performance in the acetone oxidation than Mn2/MC regardless this sample had higher Mn2O3 loading (11 wt%). This effect was related to the active phase crystal characteristics as well as to the textural properties induced by the PILC washcoating.