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Author |
He, Z.; Maurice, J.-L.; Gohier, A.; Lee, C.S.; Pribat, D.; Cojocaru, C.S. |
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Title |
Iron catalysts for the growth of carbon nanofibers : Fe, Fe3C or both? |
Type |
A1 Journal article |
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Year  |
2011 |
Publication |
Chemistry of materials |
Abbreviated Journal |
Chem Mater |
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Volume |
23 |
Issue |
24 |
Pages |
5379-5387 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Iron is a widely used catalyst for the growth of carbon nanotubes (CNTs) or carbon nanofibers (CNFs) by catalytic chemical vapor deposition. However, both Fe and FeC compounds (generally, Fe3C) have been found to catalyze the growth of CNTs/CNFs, and a comparison study of their respective catalytic activities is still missing. Furthermore, the control of the crystal structure of iron-based catalysts, that is α-Fe or Fe3C, is still a challenge, which not only obscures our understanding of the growth mechanisms of CNTs/CNFs, but also complicates subsequent procedures, such as the removal of catalysts for better industrial applications. Here, we show a partial control of the phase of iron catalysts (α-Fe or Fe3C), obtained by varying the growth temperatures during the synthesis of carbon-based nanofibers/nanotubes in a plasma-enhanced chemical vapor deposition reactor. We also show that the structure of CNFs originating from Fe3C is bamboo-type, while that of CNFs originating from Fe is not. Moreover, we directly compare the growth rates of carbon-based nanofibers/nanotubes during the same experiments and find that CNFs/CNTs grown by α-Fe nanoparticles are longer than CNFs grown from Fe3C nanoparticles. The influence of the type of catalyst on the growth of CNFs is analyzed and the corresponding possible growth mechanisms, based on the different phases of the catalysts, are discussed. |
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Publisher |
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Place of Publication |
Washington, D.C. |
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Wos |
000298197300014 |
Publication Date |
2011-11-10 |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0897-4756;1520-5002; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
91 |
Open Access |
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Notes |
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Approved |
Most recent IF: 9.466; 2011 IF: 7.286 |
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Call Number |
UA @ lucian @ c:irua:94297 |
Serial |
1748 |
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Author |
He, Z.; Lee, C.S.; Maurice, J.-L.; Pribat, D.; Haghi-Ashtiani, P.; Cojocaru, C.S. |
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Title |
Vertically oriented nickel nanorod/carbon nanofiber core/shell structures synthesized by plasma-enhanced chemical vapor deposition |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Carbon |
Abbreviated Journal |
Carbon |
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Volume |
49 |
Issue |
14 |
Pages |
4710-4718 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Plasma-enhanced chemical vapor deposition, without a nickel-containing gaseous precursor, was used to synthesize continuous nickel (Ni) nanorods inside the hollow cavity of carbon nanofibers (CNFs), thus forming vertically aligned Ni/CNF core/shell structures. Scanning and transmission electron microscopic images indicate that the elongated Ni nanorods originate from the catalyst particles at the tips of the CNFs and that their formation is due to the effect of extrusion induced by the compressive force of the graphene layers during growth. Different from previous work, each vertically-aligned core/shell structure reported is totally isolated from its neighbors. Continuous Ni nanorods are found to separate into smaller ones with increasing growth time, which was ascribed to (i) the limited amount of Ni available in the tip of the CNF, (ii) the polycrystalline nature of the Ni nanorods and (iii) the combined effects of the compressive stresses on the side of the Ni nanorods and of the tensile stress along their axis. |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000295308300010 |
Publication Date |
2011-06-30 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0008-6223; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.337 |
Times cited |
16 |
Open Access |
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Notes |
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Approved |
Most recent IF: 6.337; 2011 IF: 5.378 |
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Call Number |
UA @ lucian @ c:irua:92782 |
Serial |
3841 |
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