3rd Users' Conference of IT4Innovations

Periodic DFT study of siting of divalent cations in silicon-rich zeolites

5 Nov 2019, 17:30

15m

atrium (IT4Innovations)

User's talk Users' talks Users' Talks III - Chairman Tomas Kozubek - IT4Innovations

Speaker

Dr Stepan Sklenak (J. Heyrovsky Institute of Physical Chemistry)

Description

Zeolites are crystalline microporous aluminosilicates widely used as molecular sieves and catalysts in industrial chemical processes. Silicon-rich zeolites (Si/Al > 8), such as ZSM-5, mordenite, ferrierite, and beta zeolite, represent catalytic materials with wide industrial applications due to their high stability and unique properties of cationic species in these matrices. The positively charged extra-framework divalent cations, which are the active sites in catalysis, balance the negative charge of two framework AlO4- tetrahedra located in 6-rings and 8-rings in dehydrated zeolite matrixes. The determination of the local structure of divalent cations is of great importance because the local structure affects the catalytic activity and selectivity. In the case of silicon-rich zeolites, the application of diffraction methods for the analysis of the siting of extra-framework cationic species in zeolite frameworks is significantly limited. In this contribution, we will present our results regarding the siting of Co(II),1-5 Fe(II),5-6 and Cu(II)1 in the zeolites of the FER,1, 5-6 BEA,2 TNU-9,3 and SSZ-13.4 Furthermore, the results of the investigation of the formation of the very reactive Alpha oxygen on Co(II) and Fe(II) cations,5 which is able to selectively oxidize methane to methanol at room temperature, will be presented.

Reference

1. Sklenak, S.; Andrikopoulos, P. C.; Whittleton, S. R.; Jirglova, H.; Sazama, P.; Benco, L.; Bucko, T.; Hafner, J.; Sobalik, Z. J. Phys. Chem. C 2013, 117, 3958-3968.
2. Sazama, P.; Tabor, E.; Klein, P.; Wichterlova, B.; Sklenak, S.; Mokrzycki, L.; Pashkkova, V.; Ogura, M.; Dedecek, J. J. Catal. 2016, 333, 102-114.
3. Karcz, R.; Dedecek, J.; Supronowicz, B.; Thomas, H. M.; Klein, P.; Tabor, E.; Sazama, P.; Pashkova, V.; Sklenak, S. Chem. Eur. J. 2017, 23, 8857-8870.
4. Mlekodaj, K.; Dedecek, J.; Pashkova, V.; Tabor, E.; Klein, P.; Urbanova, M.; Karcz, R.; Sazama, P.; Whittleton, S. R.; Thomas, H. M.; Fishchuk, A. V.; Sklenak, S. J. Phys. Chem. C 2019, 123, 7968-7987.
5. Tabor, E.; Lemishka, M.; Sobalik, Z.; Mlekodaj, K.; Andrikopoulos, P. C.; Dedecek, J.; Sklenak, S. Commun. Chem. 2019, 2.
6. Sklenak, S.; Andrikopoulos, P. C.; Boekfa, B.; Jansang, B.; Novakova, J.; Benco, L.; Bucko, T.; Hafner, J.; Dedecek, J.; Sobalik, Z. J. Catal. 2010, 272, 262-274.