TY - JOUR
T1 - Preferential dealumination of Zn/H-ZSM-5 and its high and stable activity for ethane dehydroaromatization
AU - Saito, Hikaru
AU - Inagaki, Satoshi
AU - Kojima, Kiria
AU - Han, Qiao
AU - Yabe, Tomohiro
AU - Ogo, Shuhei
AU - Kubota, Yoshihiro
AU - Sekine, Yasushi
N1 - Funding Information:
H. Saito acknowledges the Leading Graduate Program in Science and Engineering, Waseda University from MEXT, Japan. A part of this study was supported by JST-CREST.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2018
Y1 - 2018
N2 - The effect of steam treatment on Zn/H-ZSM-5 catalysts prepared by an ion-exchange method for non-oxidative ethane dehydroaromatization was investigated. Steam treatment of Zn/H-ZSM-5 after Zn loading improved its catalytic stability on aromatic hydrocarbon formation including benzene, toluene and xylene. Temperature programmed oxidation measurements demonstrated that the steam treatment brought suppression of coke formation and it contributed to the improvement in the catalytic stability. Characterization of the local structure of the zeolites by 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy revealed that dealumination of the framework Al in the MFI structure proceeded by steam treatment. Results of temperature programmed desorption of ammonia indicate the decrease in the amount of acid sites by the steam treatment. The slight changes in Zn content and its electronic state indicated that bared Al related with H+, not with Zn2+, in the MFI structure was preferentially dealuminated by steam treatment. The preferential dealumination led to suppression of coke formation by the selective removal of undesirable Brønsted acid sites.
AB - The effect of steam treatment on Zn/H-ZSM-5 catalysts prepared by an ion-exchange method for non-oxidative ethane dehydroaromatization was investigated. Steam treatment of Zn/H-ZSM-5 after Zn loading improved its catalytic stability on aromatic hydrocarbon formation including benzene, toluene and xylene. Temperature programmed oxidation measurements demonstrated that the steam treatment brought suppression of coke formation and it contributed to the improvement in the catalytic stability. Characterization of the local structure of the zeolites by 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy revealed that dealumination of the framework Al in the MFI structure proceeded by steam treatment. Results of temperature programmed desorption of ammonia indicate the decrease in the amount of acid sites by the steam treatment. The slight changes in Zn content and its electronic state indicated that bared Al related with H+, not with Zn2+, in the MFI structure was preferentially dealuminated by steam treatment. The preferential dealumination led to suppression of coke formation by the selective removal of undesirable Brønsted acid sites.
KW - Coke deposition
KW - Ethane dehydroaromatization
KW - Preferential dealumination
KW - Zeolite catalyst
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U2 - 10.1016/j.apcata.2017.09.024
DO - 10.1016/j.apcata.2017.09.024
M3 - Article
AN - SCOPUS:85030111717
SN - 0926-860X
VL - 549
SP - 76
EP - 81
JO - Applied Catalysis A: General
JF - Applied Catalysis A: General
ER -