Modification of MCM-22 Zeolite and Its Derivatives with Iron for the Application in N2O Decomposition

Layered 2D zeolite MCM-22 and its delaminated derivative, ITQ-2, were modified with iron, by different methods (ion-exchange and direct synthesis), and with the use of different precursors (FeSO4.7H2O, Fe(NO3)3.9H2O, and [Fe3(OCOCH3)7.OH.2H2O]NO3 oligocations. The applied modifications were aimed at optimization of iron form in the samples (aggregation, amount, location, and reducibility), in order to achieve the highest catalytic activity in the N2O decomposition. The synthesis of the samples was verified with the use of XRD (X-Ray Diffraction), N2-sorption and ICP-OES (Inductively Coupled Plasma Optical Emission Spectroscopy) techniques, while the form of iron in the samples was investigated byUV¿vis-DRS (UV¿vis diffuse reflectance spectroscopy),H2-TPR (Hydrogen Temperature-Programmed Reduction) and HRTEM (High-Resolution Transmission Electron Microscopy). The highest activity in the N2O decomposition presented the sample Fe(O,IE)MCM-22, prepared by ion-exchange of MCM-22 with Fe3(III) oligocations. This activity was related to the oligomeric FexOy species (the main form of iron in the sample) and the higher loading of active species (in comparison to the modification with FeSO4.7H2O).This work was carried out in the frame of project No. 0670/IP3/2016/74, from the Polish Ministry of Science and Higher Education, in the years 2016–2019. Part of the work was performed in the frame of project No. 2012/05/B/ST5/00269, from the National Science Centre (Poland). U.D. acknowledges the Spanish Government for funding (MAT2017-82288-C2-1-P)