Influence of iron aggregation on the catalytic performance of desilicated MFI in the DeNOx process

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In the present study, an influence of the iron aggregation in conventional and micro-mesoporous MFI on their catalytic activity in the NO reduction with ammonia (DeNO x process) was studied. Modification of MFI zeolite properties was done by the desilication in the presence of NaOH and TPAOH (tertapropylammonium hydroxide). In the next step, the samples were modified with iron by ion-exchange with the use of a conventional solution of Fe cations (FeSO 4 ) and a solution of iron triple-metallic aggregates (oligocations) ([Fe 3 (OAc) 6 O(H 2 O) 3 ] + ). Both of the applied modification techniques (desilication and modification with Fe 3 oligocations) increased the catalytic activity of the MFI zeolite in the DeNO x process. This increased catalytic activity was connected with changes in sample porosity, Si/Al ratio, topology, as well as aggregation and dispersion of iron species on the catalyst surface, which was investigated by N 2 -sorption, XRD, ICP, NMR, HRTEM and UV-vis-DRS techniques. • Mesoporous MFI zeolite prepared by desilication. • New method of zeolites modification by triple-metalic oligocations. • Influence of zeolite porosity, Si/Al ratio, and the used iron precursor on the amount, aggregation and dispersion of the iron species on the catalyst surface. • High catalytic activity and selectivity to nitrogen in the DeNOx process of the samples modified by desilication and with Fe3 oligocations.