Zeolites are robust and environmentally friendly heterogeneous catalysts. They contain framework metal ions, which act as Bronsted or Lewis acid sites. In particular, the Lewis acid sites (generated, e.g., by incorporated Ti, Sn, Zr, and Hf ions) catalyze selective redox reactions such as oxidation with peroxides or hydrogen transfer reactions. Type and coordination of the acid sites together with their confinement and surrounding channel environment define the site catalytic properties.
The overarching aim of this PhD project is to find parameters, which define the selectivity in selected redox reactions, use these parameters to drive the selectivity and ultimately induce a stereoselective progress of the reaction.
The project will cover 3 basic tasks: (I) synthesis of the Lewis acid zeolites, which will include known syntheses optimization to drive type of the present acid sites, (II) investigation of selected redox reactions in terms of and varying the used conditions and selectivity modifiers, and (III) characterizing acid site-substrate complexes to get insight in the reaction mechanism particularly in respect to the selectivity modifying parameters. Of these, task II will be the most important and it will include simple experiments in batch catalytic reactors as well as work with complex microflow catalytic apparatus.
Publications of the research group relevant to the topic:
Přech, J.; Kim, J.; Mazur, M.; Ryoo, R.; Čejka, J. Nanosponge TS‐1: A Fully Crystalline Hierarchical Epoxidation Catalyst, Adv. Mater. Interfaces 2021, 8, 2001288.
Shamzhy, M.; Přech, J.; Zhang, J.; Ruaux, V.; El-Siblani, H.; Mintova, S. Quantification of Lewis acid sites in 3D and 2D TS-1 zeolites: FTIR spectroscopic study, Catal. Today 2020, 345, 80-87.
Přech, J.; Pizarro, P.; Serrano, D.P.; Čejka, J. From 3D to 2D zeolite catalytic materials, Chem. Soc. Rev. 2018, 47, 8263-8306.
Přech, J. Catalytic performance of advanced titanosilicate selective oxidation catalysts - a review, Catal. Rev. Sci. Eng. 2018, 60, 71-131.
Suib, S.L.; Přech, J.; Szaniawska, E.; Čejka, J. Recent advances in tetra- (Ti, Sn, Ge, Zr, Hf) and pentavalent (Nb, V, Ta) metal substituted molecular sieve catalysis, Chem.Rev. (2022), in press.
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