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Title: Comparative investigation of Ga- and In-CHA in the non-oxidative ethane dehydrogenation reaction
Ga-and In-exchanged chabazite (CHA) zeolites with same Si/Al and metal/Al ratios were prepared via the incipient wetness impregnation method, were characterized using N-2 adsorption, electron microscopy, temperature-programed reactions and were evaluated for the ethane dehydrogenation reaction using flow microreactors. Ga-CHA has higher reaction rates and a lower activation energy of 107 kJ/mol than In-CHA (E-a = 175 kJ/mol). Rietveld refinement of the X-ray powder diffraction pattern shows that the In+ cation is predominantly located above the 6-ring of the CHA cage. It is proposed that the reaction proceeds through the alkyl mechanism based on stability of alkyl hydride intermediates as determined using DFT calculations. The oxidative addition of ethane to the metal shows much lower Gibbs free energy for Ga-CHA (+27.95 kJ/mol) vs In-CHA (+124.85 kJ/mol). These results indicate that oxidative addition may be the rate-limiting step of ethane dehydrogenation in these materials.  more » « less
Award ID(s):
1908982
PAR ID:
10571590
Author(s) / Creator(s):
; ; ; ;
Publisher / Repository:
Elsevier
Date Published:
Journal Name:
Journal of Catalysis
Volume:
413
Issue:
C
ISSN:
0021-9517
Page Range / eLocation ID:
812 to 820
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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