LAUSR

Abstract In the presented study, H-Beta zeolite and H-Beta/meso (mesoporous Beta zeolite obtained by a mesotemplate-free method) were modified with Fe3, Fe2Cr, FeCr2 and Cr3 triple-metallic aggregates (oligocations) by ion-exchange method (for comparison modification with isolated Fe cations was also done). Successful synthesis of mesoporous Beta zeolite was confirmed by several techniques such as N2-sorption, PXRD, AAS or NH3-TPD. Modified porosity and acidity of the Beta zeolite, as well as the source of metals used, influenced the form (coordination and aggregation), content and reducibility of Fe and Cr-species in the samples (UV–vis-DRS, AAS, H2-TPR). The obtained samples were tested as catalysts in the process of selective catalytic oxidation of ammonia to dinitrogen (NH3 SCO). The highest activity and selectivity for nitrogen was obtained for the bimetallic Fe Cr samples prepared by deposition of suitable oligocations.