Dehydrogenation of ethanol on an O2-4Rh/CeO2-x(1 1 1) surface: A computational study

Han Jung Li; Hui Lung Chen; Shih Feng Peng; Jia Jen Ho

doi:10.1016/j.chemphys.2009.03.018

Dehydrogenation of ethanol on an O₂-4Rh/CeO_2-x(1 1 1) surface: A computational study

Han Jung Li, Hui Lung Chen, Shih Feng Peng, Jia Jen Ho^*

^*Corresponding author for this work

Department of Chemistry

Research output: Contribution to journal › Article › peer-review

8 Citations (Scopus)

Abstract

We applied the periodic density-functional theory to investigate the dehydrogenation of ethanol on the O₂-4Rh/CeO_2-x(1 1 1) surface with an assumption that one defect site of that CeO₂ surface creates an O vacancy that an excess O₂ molecule replaces. Under these conditions, the adsorption energy of ethanol is calculated to be -16.08 kcal/mol. Before formation of a five-membered ring of an oxametallacyclic compound, the hydrogen atom of O-H and that of one β-carbon hydrogen of ethanol are eliminated. The dehydrogenation continues with the loss of two hydrogens from the α-carbon, at the same time, transforming to a four-membered ring species (Rh-CH₂C(O)-Rh). Scission of the C-C bond occurs at this stage with a dissociation barrier 14.38 kcal/mol, forming adsorbed products CO and CH₂. The ensuing steam-reforming process (CH₂ + H₂O) and the mechanism of the consecutive dehydrogenation are also discussed.

Original language	English
Pages (from-to)	141-150
Number of pages	10
Journal	Chemical Physics
Volume	359
Issue number	1-3
DOIs	https://doi.org/10.1016/j.chemphys.2009.03.018
Publication status	Published - 2009 May 18

Keywords

4Rh/CeO surface
Dehydrogenation mechanism
Density-functional theory calculation
Ethanol
Potential-energy surface

ASJC Scopus subject areas

General Physics and Astronomy
Physical and Theoretical Chemistry

Access to Document

10.1016/j.chemphys.2009.03.018

Cite this

@article{28ef56074340416e99f21be68e2a8600,

title = "Dehydrogenation of ethanol on an O2-4Rh/CeO2-x(1 1 1) surface: A computational study",

abstract = "We applied the periodic density-functional theory to investigate the dehydrogenation of ethanol on the O2-4Rh/CeO2-x(1 1 1) surface with an assumption that one defect site of that CeO2 surface creates an O vacancy that an excess O2 molecule replaces. Under these conditions, the adsorption energy of ethanol is calculated to be -16.08 kcal/mol. Before formation of a five-membered ring of an oxametallacyclic compound, the hydrogen atom of O-H and that of one β-carbon hydrogen of ethanol are eliminated. The dehydrogenation continues with the loss of two hydrogens from the α-carbon, at the same time, transforming to a four-membered ring species (Rh-CH2C(O)-Rh). Scission of the C-C bond occurs at this stage with a dissociation barrier 14.38 kcal/mol, forming adsorbed products CO and CH2. The ensuing steam-reforming process (CH2 + H2O) and the mechanism of the consecutive dehydrogenation are also discussed.",

keywords = "4Rh/CeO surface, Dehydrogenation mechanism, Density-functional theory calculation, Ethanol, Potential-energy surface",

author = "Li, {Han Jung} and Chen, {Hui Lung} and Peng, {Shih Feng} and Ho, {Jia Jen}",

note = "Funding Information: Institute of Nuclear Energy Research, Atomic Energy Council, Taiwan, under contract NL940251 and National Science Council of Republic of China under contract NSC 96-2113-M-003-007-MY3 supported this research; National Center for High-Performance Computing provided computer time. We are deeply indebted to Professor M.C. Lin from National Chiao Tung University for his persistent encouragement and instruction. ",

year = "2009",

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AU - Li, Han Jung

AU - Chen, Hui Lung

AU - Peng, Shih Feng

AU - Ho, Jia Jen

N1 - Funding Information: Institute of Nuclear Energy Research, Atomic Energy Council, Taiwan, under contract NL940251 and National Science Council of Republic of China under contract NSC 96-2113-M-003-007-MY3 supported this research; National Center for High-Performance Computing provided computer time. We are deeply indebted to Professor M.C. Lin from National Chiao Tung University for his persistent encouragement and instruction.

PY - 2009/5/18

Y1 - 2009/5/18

N2 - We applied the periodic density-functional theory to investigate the dehydrogenation of ethanol on the O2-4Rh/CeO2-x(1 1 1) surface with an assumption that one defect site of that CeO2 surface creates an O vacancy that an excess O2 molecule replaces. Under these conditions, the adsorption energy of ethanol is calculated to be -16.08 kcal/mol. Before formation of a five-membered ring of an oxametallacyclic compound, the hydrogen atom of O-H and that of one β-carbon hydrogen of ethanol are eliminated. The dehydrogenation continues with the loss of two hydrogens from the α-carbon, at the same time, transforming to a four-membered ring species (Rh-CH2C(O)-Rh). Scission of the C-C bond occurs at this stage with a dissociation barrier 14.38 kcal/mol, forming adsorbed products CO and CH2. The ensuing steam-reforming process (CH2 + H2O) and the mechanism of the consecutive dehydrogenation are also discussed.

AB - We applied the periodic density-functional theory to investigate the dehydrogenation of ethanol on the O2-4Rh/CeO2-x(1 1 1) surface with an assumption that one defect site of that CeO2 surface creates an O vacancy that an excess O2 molecule replaces. Under these conditions, the adsorption energy of ethanol is calculated to be -16.08 kcal/mol. Before formation of a five-membered ring of an oxametallacyclic compound, the hydrogen atom of O-H and that of one β-carbon hydrogen of ethanol are eliminated. The dehydrogenation continues with the loss of two hydrogens from the α-carbon, at the same time, transforming to a four-membered ring species (Rh-CH2C(O)-Rh). Scission of the C-C bond occurs at this stage with a dissociation barrier 14.38 kcal/mol, forming adsorbed products CO and CH2. The ensuing steam-reforming process (CH2 + H2O) and the mechanism of the consecutive dehydrogenation are also discussed.

KW - 4Rh/CeO surface

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KW - Density-functional theory calculation

KW - Ethanol

KW - Potential-energy surface

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