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First-principles study of the mechanism of carbon deposition on Fe(111) surface and subsurface

Authors :
Chun-Fang Huo
Xing-Wu Liu
Jianguo Wang
Li Yong-Wang
Source :
Journal of Fuel Chemistry and Technology. 40:202-209
Publication Year :
2012
Publisher :
Elsevier BV, 2012.

Abstract

A theoretical study of the carbon atoms adsorption and diffusion on the surface and into the subsurface of Fe (111) is performed using DFT calculations. Before the carbon coverages up to 1 ML, the adsorbed carbons tend to exist in an isolated atomic state and cause a reconstruction of Fe (111) surface. The configurations of “mC2+nC” are energetically favorable on the Fe (111) surface at 1 ML ≤ θC ≤ 2 ML. At a higher coverage, complicated adsorbed patterns such as chains and islands are found, and we predict that these carbon islands can function as the nucleation center of the precipitation of graphite or carbon nanotubes on the Fe(111) surface. In the subsurface region, the carbon atom prefers the octahedral site. The barriers for diffusion on and into the Fe (111) surface and subsurface are 0.45 eV and 0.73 eV, respectively. Actually, C2 formation is thermodynamically favored, whereas C migration into the subsurface region is kinetically feasible.

Details

ISSN :
18725813
Volume :
40
Database :
OpenAIRE
Journal :
Journal of Fuel Chemistry and Technology
Accession number :
edsair.doi...........fb9d6134392b1be66c2f949417acd5e0
Full Text :
https://doi.org/10.1016/s1872-5813(12)60010-3