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Title: Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method

Abstract

We have developed a ReaxFF reactive force field to describe hydrogen adsorption and dissociation on iron and iron carbide surfaces relevant for simulation of Fischer–Tropsch (FT) synthesis on iron catalysts. This force field enables large system (>>1000 atoms) simulations of hydrogen related reactions with iron. The ReaxFF force field parameters are trained against a substantial amount of structural and energetic data including the equations of state and heats of formation of iron and iron carbide related materials, as well as hydrogen interaction with iron surfaces and different phases of bulk iron. We have validated the accuracy and applicability of ReaxFF force field by carrying out molecular dynamics simulations of hydrogen adsorption, dissociation and recombination on iron and iron carbide surfaces. The barriers and reaction energies for molecular dissociation on these two types of surfaces have been compared and the effect of subsurface carbon on hydrogen interaction with iron surface is evaluated. We found that existence of carbon atoms at subsurface iron sites tends to increase the hydrogen dissociation energy barrier on the surface, and also makes the corresponding hydrogen dissociative state relatively more stable compared to that on bare iron. These properties of iron carbide will affect the dissociation ratemore » of H{sub 2} and will retain more surface hydride species, thus influencing the dynamics of the FT synthesis process.« less

Authors:
; ;
Publication Date:
Research Org.:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States). In-house Research
Sponsoring Org.:
USDOE Office of Fossil Energy (FE)
Contributing Org.:
National Energy Technology Laboratory; The Pennsylvania State University
OSTI Identifier:
1081572
Report Number(s):
TPR-3773
Journal ID: ISSN 1022--5528
DOE Contract Number:  
DE-FE0004000
Resource Type:
Journal Article
Journal Name:
Topics in Catalysis
Additional Journal Information:
Journal Volume: 55; Journal Issue: 5-6; Journal ID: ISSN 1022--5528
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Zou, Chenyu, van Duin, Adri C.T., and Sorescu, Dan C. Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method. United States: N. p., 2012. Web. doi:10.1007/s11244-012-9796-0.
Zou, Chenyu, van Duin, Adri C.T., & Sorescu, Dan C. Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method. United States. https://doi.org/10.1007/s11244-012-9796-0
Zou, Chenyu, van Duin, Adri C.T., and Sorescu, Dan C. Fri . "Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method". United States. https://doi.org/10.1007/s11244-012-9796-0. https://www.osti.gov/servlets/purl/1081572.
@article{osti_1081572,
title = {Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method},
author = {Zou, Chenyu and van Duin, Adri C.T. and Sorescu, Dan C.},
abstractNote = {We have developed a ReaxFF reactive force field to describe hydrogen adsorption and dissociation on iron and iron carbide surfaces relevant for simulation of Fischer–Tropsch (FT) synthesis on iron catalysts. This force field enables large system (>>1000 atoms) simulations of hydrogen related reactions with iron. The ReaxFF force field parameters are trained against a substantial amount of structural and energetic data including the equations of state and heats of formation of iron and iron carbide related materials, as well as hydrogen interaction with iron surfaces and different phases of bulk iron. We have validated the accuracy and applicability of ReaxFF force field by carrying out molecular dynamics simulations of hydrogen adsorption, dissociation and recombination on iron and iron carbide surfaces. The barriers and reaction energies for molecular dissociation on these two types of surfaces have been compared and the effect of subsurface carbon on hydrogen interaction with iron surface is evaluated. We found that existence of carbon atoms at subsurface iron sites tends to increase the hydrogen dissociation energy barrier on the surface, and also makes the corresponding hydrogen dissociative state relatively more stable compared to that on bare iron. These properties of iron carbide will affect the dissociation rate of H{sub 2} and will retain more surface hydride species, thus influencing the dynamics of the FT synthesis process.},
doi = {10.1007/s11244-012-9796-0},
url = {https://www.osti.gov/biblio/1081572}, journal = {Topics in Catalysis},
issn = {1022--5528},
number = 5-6,
volume = 55,
place = {United States},
year = {2012},
month = {6}
}