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Title: Density functional theory study of acetaldehyde hydrodeoxygenation on MoO3

Abstract

Periodic spin-polarized density functional theory calculations were performed to investigate acetaldehyde (CH3CHO) hydrodeoxygenation on the reduced molybdenum trioxide (MoO3) surface. The perfect O-terminated α-MoO3(010) surface is reduced to generate an oxygen defect site in the presence of H2. H2 dissociatively adsorbs at the surface oxygen sites forming two surface hydroxyls, which can recombine into a water molecule weakly bound at the Mo site. A terminal oxygen (Ot) defect site thus forms after water desorption. CH3CHO adsorbs at the O-deficient Mo site via either the sole O-Mo bond or the O-Mo and the C-O double bonds. The possible reaction pathways of the adsorbed CH3CHO with these two configurations were thoroughly examined using the dimer searching method. Our results show that the ideal deoxygenation of CH3CHO leading to ethylene (C2H4) on the reduced MoO3(010) surface is feasible. The adsorbed CH3CHO first dehydrogenate into CH2CHO by reacting with a neighboring terminal Ot. The hydroxyl (OtH) then hydrogenates CH2CHO into CH2CH2O to complete the hydrogen transfer cycle with an activation barrier of 1.39 eV. The direct hydrogen transfer from CH3CHO to CH2CH2O is unlikely due to the high barrier of 2.00 eV. The produced CH2CH2O readily decomposes into C2H4 that directly releases to themore » gas phase, and regenerates the Ot atom on the Mo site. As a result, the reduced MoO3(010) surface is reoxidized to the perfect MoO3(010) surface after CH3CHO deoxygenation. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1012864
Report Number(s):
PNNL-SA-77029
Journal ID: ISSN 1932-7447; 42292; BM0101010; TRN: US201110%%388
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry C, 115(16):8155-8164
Additional Journal Information:
Journal Volume: 115; Journal Issue: 16; Journal ID: ISSN 1932-7447
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ACETALDEHYDE; ATOMS; DEFECTS; DESORPTION; DIMERS; DOUBLE BONDS; ETHYLENE; FUNCTIONALS; HYDROGEN TRANSFER; MOLYBDENUM; OXYGEN; WATER; Deoxygenation; Acetaldehyde; MoO3; Density functional theory; Reaction mechanism; Environmental Molecular Sciences Laboratory

Citation Formats

Mei, Donghai, Karim, Ayman M, and Wang, Yong. Density functional theory study of acetaldehyde hydrodeoxygenation on MoO3. United States: N. p., 2011. Web. doi:10.1021/jp200011j.
Mei, Donghai, Karim, Ayman M, & Wang, Yong. Density functional theory study of acetaldehyde hydrodeoxygenation on MoO3. United States. doi:10.1021/jp200011j.
Mei, Donghai, Karim, Ayman M, and Wang, Yong. Wed . "Density functional theory study of acetaldehyde hydrodeoxygenation on MoO3". United States. doi:10.1021/jp200011j.
@article{osti_1012864,
title = {Density functional theory study of acetaldehyde hydrodeoxygenation on MoO3},
author = {Mei, Donghai and Karim, Ayman M and Wang, Yong},
abstractNote = {Periodic spin-polarized density functional theory calculations were performed to investigate acetaldehyde (CH3CHO) hydrodeoxygenation on the reduced molybdenum trioxide (MoO3) surface. The perfect O-terminated α-MoO3(010) surface is reduced to generate an oxygen defect site in the presence of H2. H2 dissociatively adsorbs at the surface oxygen sites forming two surface hydroxyls, which can recombine into a water molecule weakly bound at the Mo site. A terminal oxygen (Ot) defect site thus forms after water desorption. CH3CHO adsorbs at the O-deficient Mo site via either the sole O-Mo bond or the O-Mo and the C-O double bonds. The possible reaction pathways of the adsorbed CH3CHO with these two configurations were thoroughly examined using the dimer searching method. Our results show that the ideal deoxygenation of CH3CHO leading to ethylene (C2H4) on the reduced MoO3(010) surface is feasible. The adsorbed CH3CHO first dehydrogenate into CH2CHO by reacting with a neighboring terminal Ot. The hydroxyl (OtH) then hydrogenates CH2CHO into CH2CH2O to complete the hydrogen transfer cycle with an activation barrier of 1.39 eV. The direct hydrogen transfer from CH3CHO to CH2CH2O is unlikely due to the high barrier of 2.00 eV. The produced CH2CH2O readily decomposes into C2H4 that directly releases to the gas phase, and regenerates the Ot atom on the Mo site. As a result, the reduced MoO3(010) surface is reoxidized to the perfect MoO3(010) surface after CH3CHO deoxygenation. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.},
doi = {10.1021/jp200011j},
journal = {Journal of Physical Chemistry C, 115(16):8155-8164},
issn = {1932-7447},
number = 16,
volume = 115,
place = {United States},
year = {2011},
month = {4}
}