TY - JOUR

T1 - n-Butane transformation on Zn/H-BEA. The effect of different Zn species (Zn2+ and ZnO) on the reaction performance

AU - Gabrienko, Anton A.

AU - Arzumanov, Sergei S.

AU - Lashchinskaya, Zoya N.

AU - Toktarev, Alexander V.

AU - Freude, Dieter

AU - Haase, Jürgen

AU - Stepanov, Alexander G.

PY - 2020/11/1

Y1 - 2020/11/1

N2 - Using solid-state 1H and 13C MAS NMR spectroscopy, the performance of H-BEA zeolite, modified with either Zn2+ cations (Zn2+/H-BEA) or ZnO clusters (ZnO/H-BEA), has been investigated with respect to n-butane transformation by aromatization and hydrogenolysis pathways. 13C-labeled n-butane has been used to follow the main stages of n-butane transformation on both Zn2+/H-BEA and ZnO/H-BEA with 13C MAS NMR at 298–623 K. Similar surface species, including n-butylzinc, n-butene, allyl-like oligomers, are formed as the intermediates on both zeolites. The kinetics of n-butane transformation has been monitored with 1H MAS NMR in situ at 543–573 K. Kinetics modeling reveals that Zn2+/H-BEA is more active for n-butane transformation than ZnO/H-BEA. A remarkable difference in the rates and the pathways of hydrogenolysis for Zn2+/H-BEA and ZnO/H-BEA has also been established. Propane and methane are hydrogenolysis products on ZnO/H-BEA whereas ethane is produced by the reaction on Zn2+/H-BEA. 13C NMR data and the kinetics analysis provide an insight on the occurrence of joint methane and n-butane conversion on Zn-modified zeolites under non-oxidative conditions.

AB - Using solid-state 1H and 13C MAS NMR spectroscopy, the performance of H-BEA zeolite, modified with either Zn2+ cations (Zn2+/H-BEA) or ZnO clusters (ZnO/H-BEA), has been investigated with respect to n-butane transformation by aromatization and hydrogenolysis pathways. 13C-labeled n-butane has been used to follow the main stages of n-butane transformation on both Zn2+/H-BEA and ZnO/H-BEA with 13C MAS NMR at 298–623 K. Similar surface species, including n-butylzinc, n-butene, allyl-like oligomers, are formed as the intermediates on both zeolites. The kinetics of n-butane transformation has been monitored with 1H MAS NMR in situ at 543–573 K. Kinetics modeling reveals that Zn2+/H-BEA is more active for n-butane transformation than ZnO/H-BEA. A remarkable difference in the rates and the pathways of hydrogenolysis for Zn2+/H-BEA and ZnO/H-BEA has also been established. Propane and methane are hydrogenolysis products on ZnO/H-BEA whereas ethane is produced by the reaction on Zn2+/H-BEA. 13C NMR data and the kinetics analysis provide an insight on the occurrence of joint methane and n-butane conversion on Zn-modified zeolites under non-oxidative conditions.

KW - Aromatization

KW - Hydrogenolysis

KW - Kinetics

KW - Mechanism

KW - n-butane

KW - Solid-state NMR

KW - Zeolite BEA

KW - Zn cations

KW - ZnO clusters

KW - SOLID-STATE NMR

KW - SULFATED ZIRCONIA

KW - C-13 MAS NMR

KW - BUTENE CONVERSION

KW - IN-SITU NMR

KW - METHANE ACTIVATION

KW - MODIFIED ZSM-5 ZEOLITES

KW - LIGHT ALKANES

KW - BRONSTED ACID SITES

KW - PROPANE AROMATIZATION

UR - http://www.scopus.com/inward/record.url?scp=85090047528&partnerID=8YFLogxK

U2 - 10.1016/j.jcat.2020.08.011

DO - 10.1016/j.jcat.2020.08.011

M3 - Article

AN - SCOPUS:85090047528

VL - 391

SP - 69

EP - 79

JO - Journal of Catalysis

JF - Journal of Catalysis

SN - 0021-9517

ER -