TY - JOUR
T1 - A First-Principles Investigation of Gas-Phase Ring-Opening Reaction of Furan over HZSM-5 and Ga-Substituted ZSM-5
AU - Zhou, Mingxia
AU - Cheng, Lei
AU - Liu, Bin
AU - Curtiss, Larry A.
AU - Assary, Rajeev S.
N1 - Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/8/21
Y1 - 2019/8/21
N2 - The furan ring-opening reaction using three catalytic models, HZSM-5, the extra-framework sites [GaO]/ZSM-5, and [Ga(OH)2]/ZSM-5, was investigated using periodic density functional theory as a model reaction for mechanistic understanding of catalytic vapor phase biomass upgrading. The formation of formyl allene from the furan was investigated in detail by computing the energy profiles and reaction barriers. Based on the computed free energy profiles, the HZSM-5 and [Ga(OH)2]/ZSM-5 are active catalysts, whereas [GaO]/ZSM-5 is not active for the furan ring-opening reaction. In HZSM-5, the likely rate-controlling step is furan CH2-O bond cleavage upon protonation (1.70 eV). The computed energy difference between the highest and lowest points in the free energy profile is 1.89 eV. The [Ga(OH)2]+ is likely the catalytic center for the gallium-incorporated ZSM-5 catalyst. The rate-controlling step is a hydrogen transfer reaction, which requires a reaction barrier of 2.48 eV. The computed energy difference between the highest and lowest points in the Ga(OH)2 catalyzed free energy profile is 2.61 eV. These computational studies provide new mechanistic understanding of the role of catalytic extra-framework sites in the vapor phase upgrading reactions.
AB - The furan ring-opening reaction using three catalytic models, HZSM-5, the extra-framework sites [GaO]/ZSM-5, and [Ga(OH)2]/ZSM-5, was investigated using periodic density functional theory as a model reaction for mechanistic understanding of catalytic vapor phase biomass upgrading. The formation of formyl allene from the furan was investigated in detail by computing the energy profiles and reaction barriers. Based on the computed free energy profiles, the HZSM-5 and [Ga(OH)2]/ZSM-5 are active catalysts, whereas [GaO]/ZSM-5 is not active for the furan ring-opening reaction. In HZSM-5, the likely rate-controlling step is furan CH2-O bond cleavage upon protonation (1.70 eV). The computed energy difference between the highest and lowest points in the free energy profile is 1.89 eV. The [Ga(OH)2]+ is likely the catalytic center for the gallium-incorporated ZSM-5 catalyst. The rate-controlling step is a hydrogen transfer reaction, which requires a reaction barrier of 2.48 eV. The computed energy difference between the highest and lowest points in the Ga(OH)2 catalyzed free energy profile is 2.61 eV. These computational studies provide new mechanistic understanding of the role of catalytic extra-framework sites in the vapor phase upgrading reactions.
UR - http://www.scopus.com/inward/record.url?scp=85071264100&partnerID=8YFLogxK
U2 - 10.1021/acs.iecr.9b01969
DO - 10.1021/acs.iecr.9b01969
M3 - Article
AN - SCOPUS:85071264100
SN - 0888-5885
VL - 58
SP - 15127
EP - 15133
JO - Industrial and Engineering Chemistry Research
JF - Industrial and Engineering Chemistry Research
IS - 33
ER -