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Splitting Dioxygen over Distant Binuclear Fe Sites in Zeolites. Effect of the Local Arrangement and Framework Topology
Autoři: Tabor Edyta | Lemishka Mariia | Olszowka Joanna E | Mlekodaj Kinga | Dedecek Jiri | Andrikopoulos Prokopis C | Sklenak Stepan
Rok: 2021
Druh publikace: článek v odborném periodiku
Název zdroje: ACS Catalysis
Název nakladatele: American Chemical Society
Místo vydání: Washington
Strana od-do: 2340-2355
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Štěpení kyslíku na vzdálených dvoujaderných Fe centrech v zeolitech. Efekt lokálního uspořádání a mřížkové topologie Aktivace kyslíku je extrémně důležitá z důvodu potenciálu pro transformaci metanu na vhodné produkty a aplikace v jiných oxidačních reakcích. Vzdálená dvoujaderná Fe(II) centra v Fe-FER vykázala štěpení kyslíku při pokojové teplotě do formy páru aktivních kyslíkových druhů a následnou oxidaci metanu na metanol při pokojové teplotě. alfa kyslík; oxidace metanu; selektivní oxidace uhlovodíků; DFT; beta zeolit
eng Splitting Dioxygen over Distant Binuclear Fe Sites in Zeolites. Effect of the Local Arrangement and Framework Topology Activation of dioxygen is of extreme importance due to its potential for transformation of methane to valuable products and applications in other selective oxidation reactions. Distant binuclear cationic Fe(II) centers in Fe-ferrierite were shown to split dioxygen at room temperature to form a pair of very active oxygen species (i.e., alpha-oxygens) and subsequently oxidize methane to methanol at room temperature as well. Our study reveals that the activity in splitting dioxygen represents a general property of the distant binuclear cationic Fe(II) centers stabilized in the aluminosilicate matrix. Computational models of the ferrierite, beta, A, and mordenite zeolites with various Al sitings in the rings forming the cationic sites were investigated by periodic DFT calculations including molecular dynamics simulations. The results reveal that the Fe(II) sites stabilized in various zeolite matrices can split dioxygen if the two cationic sites forming the distant binuclear Fe(II) centers (i) face each other, (ii) are parallel, and (iii) are axial, and (iv) the Fe center dot center dot center dot Fe distance lies in a narrow range from ca. 7 to ca. 8 A (ca. 7-ca. 10 A for the distance between the two rings (forming the corresponding cationic sites) in empty zeolites since this distance is equal to or larger than the Fe center dot center dot center dot Fe distances). Our study opens the possibility of developing Fe-zeolite-based systems for the dioxygen activation employed for direct oxidations using various zeolite matrices. alpha oxygen; oxidation of methane; utilization of methane; selective oxidation of hydrocarbons; direct oxidation of hydrocarbons; transition metal-exchanged zeolites; density functional theory; ferrierite; beta zeolite