How far away are iron carbide clusters from the bulk?

Title How far away are iron carbide clusters from the bulk?
Authors L. Zheng; X. Liu; Y. Meng; Y. Zhou; W. Guo; Q. Peng; Y. Yang; H. Jiao; Y.W. Li; X.D. Wen
Journal Phys Chem Chem Phys
DOI 10.1039/c6cp06224e
Abstract

Combining the basin hopping structure searching algorithm and density functional theory, the iron carbide clusters, FexCy (x ? 8 and y ? 8), and clusters with various stoichiometries (Fe2nCn, Fe3nCn, FenC2n, FenC3n and FenC4n (n = 1-7), Fe5nC2n, and Fe4nCn (n = 1-5)) are predicted. The stable structures of iron rich carbide clusters are composed of C-C dimers or single C atoms on the surface of the clusters, which are remarkably different from their corresponding bulk structures, where the carbon atoms are atomically distributed in the iron matrix. The most stable carbon rich clusters are highly diverse in topology (bowl, basket, plane, shoe, necklace, etc.) with long carbon chains. The Bader charge analysis shows that the size effect on iron carbide clusters is an electronic tuning. Large carbon-rich clusters appear even under low carbon chemical potentials, whereas small iron-rich clusters are only energetically stable in high carbon chemical potentials, which indicates that changing the carbon chemical potential can tune the morphology (size and stoichiometry) of the iron carbide clusters. These results may help us understand the catalytic activity of iron and iron carbides in reactions such as the Fischer-Tropsch synthesis and the carbon nanotube formation process.

Citation L. Zheng; X. Liu; Y. Meng; Y. Zhou; W. Guo; Q. Peng; Y. Yang; H. Jiao; Y.W. Li; X.D. Wen.How far away are iron carbide clusters from the bulk?. Phys Chem Chem Phys. 2016;18(48):3294432951. doi:10.1039/c6cp06224e

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Iron

See more Iron products. Iron (atomic symbol: Fe, atomic number: 26) is a Block D, Group 8, Period 4 element with an atomic weight of 55.845. The number of electrons in each of Iron's shells is 2, 8, 14, 2 and its electron configuration is [Ar] 3d6 4s2. Iron Bohr ModelThe iron atom has a radius of 126 pm and a Van der Waals radius of 194 pm. Iron was discovered by humans before 5000 BC. In its elemental form, iron has a lustrous grayish metallic appearance. Iron is the fourth most common element in the Earth's crust and the most common element by mass forming the earth as a whole. Iron is rarely found as a free element, since it tends to oxidize easily; it is usually found in minerals such as magnetite, hematite, goethite, limonite, or siderite.Elemental Iron Though pure iron is typically soft, the addition of carbon creates the alloy known as steel, which is significantly stronger.

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