Center for Functional Nanomaterials Seminar

Department of Chemistry, NIS Centre and INSTM Reference Center, University of Turin, Turin, Italy. University of Oslo, Department of Chemistry, Oslo, Norway. Cu-exchanged chabazite (Cu-CHA) is currently the object of intensive research efforts to rationalize its outstanding performance in the NH3-assisted selective catalytic reduction (SCR) of NOx1 and its recently proved activity in the direct conversion of methane to methanol (MTM).2 Cu is usually introduced into the zeolites via aqueous ion exchange, resulting in the formation of [Cu(OH)]+ and/or Cu2+ counterions. Recent works pointed out that the relative abundance of [Cu(OH)]+ and Cu2+ depends on the Cu/Al and Si/Al ratios, and proposed that only [Cu(OH)]+ can be 'self-reduced' to Cu+ sites during activation in inert atmosphere.3 To shed light on this aspect, which has important implications on the design and understanding of active catalysts for both SCR and MTM reactions, we prepared a large set of Cu-CHA samples with different Cu/Al and Si/Al ratios. These were characterized in situ by X ray Absorption (XAS) and FTIR of adsorbed probe molecules, to follow Cu speciation and evolution during activation in different conditions.4,5 Use of multivariate data-modelling allowed us to access an unprecedented level of understanding in a complex multi-component catalytic system, yielding novel insights into the birth of Cu-active sites in the cages of the CHA zeolite.4 For more details on: "Cu-CHA – a model system for applied selective redox catalysis", see the review by Borfecchia et al. 6 References: 1 Beale, A. M.; Gao, F.; Lezcano-Gonzalez, I.; Peden, C. H. F.; Szanyi, J. Chem Soc Rev 2015, 44, 7371-7405. 2 Wulfers M.J., Teketel, S., Ipek, B., Lobo R. F., Chem. Commun. 2015, 51, 4447-4450. 3 Paolucci, C.; Parekh, A. A.; Khurana, I.; Di Iorio, J. R.; Li, H.; Caballero, J. D. A.; Shih, A. J.; Anggara, T.; Delgass, et al. J Am Chem Soc 201