Kalcinované hydrotalcit-zeolitové sloučeniny jako katalyzátory pro přímý katalytický rozklad NO

Abstract

This thesis deals with the preparation and characterization of composite catalysts based on zeolites (Beta, ZSM-5) and potassium-modified Co–Mn–Al mixed oxides for the direct catalytic decomposition of NO. Various preparation methods and the effect of potassium incorporation on their properties were studied. The physicochemical characteristics were analyzed using AAS, XRD, TPR-H₂, TPD-CO₂, TPD-NH₃, TPD-NO, and N₂ physisorption methods. The results show that the combination of a zeolite support and mixed oxides allows for the modification of both the structure and surface properties. Despite optimization of the preparation and potassium modification, the prepared catalysts did not show activity for the direct decomposition of NO due to the unsuitable distribution of potassium. Its incorporation into the zeolite structure, confirmed by AAS, XRD, TPD-CO₂, and TPR-H₂, prevented sufficient contact with the active cobalt phase. This conclusion is supported by the absence of desorption peaks in TPD-NO corresponding to the decomposition of the NO₂⁻ intermediate and, simultaneously, by the absence of moderately strong basic sites typically associated with the effect of a promoter.