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Propane activation on Zn-modified zeolite. The effect of the nature of Zn-species on the mechanism of H/D hydrogen exchange of the alkane with Brønsted acid sites. / Arzumanov, Sergei S.; Gabrienko, Anton A.; Toktarev, Alexander V. et al.
In: Journal of Catalysis, Vol. 378, 01.10.2019, p. 341-352.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Propane activation on Zn-modified zeolite. The effect of the nature of Zn-species on the mechanism of H/D hydrogen exchange of the alkane with Brønsted acid sites
AU - Arzumanov, Sergei S.
AU - Gabrienko, Anton A.
AU - Toktarev, Alexander V.
AU - Freude, Dieter
AU - Haase, Jürgen
AU - Stepanov, Alexander G.
N1 - Publisher Copyright: © 2019 Elsevier Inc. Copyright: Copyright 2019 Elsevier B.V., All rights reserved. Publisher Copyright: © 2019 Elsevier Inc.
PY - 2019/10/1
Y1 - 2019/10/1
N2 - Zn-modified zeolites exhibit high activity for the aromatization of C2+ alkanes. To understand the effect of Zn-species of different nature on propane molecules activation and transformation, the H/D hydrogen exchange of zeolite Brønsted acid sites (BAS) with deuterated propane-d8 has been investigated. Two samples of the Zn-modified zeolite containing exclusively either isolated Zn2+ cations (Zn2+/H-BEA) or small (ZnO)n clusters (ZnO/H-BEA) have been studied. Zn-species of either type work jointly with BAS and may provide the synergy effect for propane C[sbnd]H bond activation resulting in dramatic acceleration of the H/D exchange between propane and BAS. The accelerating effect of isolated Zn2+ cations is more pronounced compared to zinc oxide clusters. Moreover, the H/D exchange occurs regioselectively into the methyl groups of propane on Zn2+/H-BEA zeolite. For ZnO/H-BEA, the methylene group becomes also involved in the exchange after some induction period. Various mechanisms providing the regioselective H/D exchange on Zn2+/H-BEA as well as the involvement of the methylene group after the induction period on ZnO/H-BEA are discussed.
AB - Zn-modified zeolites exhibit high activity for the aromatization of C2+ alkanes. To understand the effect of Zn-species of different nature on propane molecules activation and transformation, the H/D hydrogen exchange of zeolite Brønsted acid sites (BAS) with deuterated propane-d8 has been investigated. Two samples of the Zn-modified zeolite containing exclusively either isolated Zn2+ cations (Zn2+/H-BEA) or small (ZnO)n clusters (ZnO/H-BEA) have been studied. Zn-species of either type work jointly with BAS and may provide the synergy effect for propane C[sbnd]H bond activation resulting in dramatic acceleration of the H/D exchange between propane and BAS. The accelerating effect of isolated Zn2+ cations is more pronounced compared to zinc oxide clusters. Moreover, the H/D exchange occurs regioselectively into the methyl groups of propane on Zn2+/H-BEA zeolite. For ZnO/H-BEA, the methylene group becomes also involved in the exchange after some induction period. Various mechanisms providing the regioselective H/D exchange on Zn2+/H-BEA as well as the involvement of the methylene group after the induction period on ZnO/H-BEA are discussed.
KW - H MAS NMR in situ
KW - Activation
KW - Brønsted acid sites
KW - H/D hydrogen exchange
KW - Mechanism
KW - Nature of Zn species
KW - Propane
KW - Zn-modified H-BEA zeolite
KW - Zn cations
KW - ZnO small clusters
KW - ZINC IONS
KW - C-13 MAS NMR
KW - ZN/MFI CATALYST
KW - DISSOCIATIVE ADSORPTION
KW - METHANE ACTIVATION
KW - HYDRIDE TRANSFER
KW - AROMATIC-HYDROCARBONS
KW - H-1 MAS NMR in situ
KW - LIGHT ALKANES
KW - HIGH-SILICA ZEOLITES
KW - ZSM-5 ZEOLITES
KW - Zn2+ cations
KW - Brensted acid sites
UR - http://www.scopus.com/inward/record.url?scp=85072571872&partnerID=8YFLogxK
U2 - 10.1016/j.jcat.2019.09.006
DO - 10.1016/j.jcat.2019.09.006
M3 - Article
AN - SCOPUS:85072571872
VL - 378
SP - 341
EP - 352
JO - Journal of Catalysis
JF - Journal of Catalysis
SN - 0021-9517
ER -
ID: 21612330