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Indexed by:期刊论文

Date of Publication:2012-06-01

Journal:CARBON

Included Journals:SCIE、EI

Volume:50

Issue:7

Page Number:2571-2580

ISSN No.:0008-6223

Abstract:Carbon nanocoils (CNCs) with controlled shape, coil diameter and coil pitch have been synthesized in a chemical vapor deposition (CVD) system by changing the reaction temperature and acetylene flow rate. It is found that three-dimensional CNCs are produced at a lower temperature (700-770 degrees C), while a higher temperature (810 degrees C) leads to the growth of straight carbon nanofibers (CNFs). CNC-CNF hybrid structures are produced by increasing growth temperature from 750 to 810 degrees C during a single synthesis run, while CNF-CNC hybrid structures are produced by decreasing the temperature from 810 to 750 degrees C. Similarly, by changing growth temperature from 750 to 810 degrees C and then back to 750 degrees C during a single run, CNC-CNF-CNC complex hybrid structures can be obtained. During the CVD process, the pulsing of acetylene and the changing of acetylene flow rate are also found to be effective in controlling the structure of CNCs. CNCs with periodic helical structures can be produced by interrupting the acetylene flow or changing its flow rate periodically. It is found that the higher the flow rate of acetylene, the smaller the coil pitch and diameter of the grown CNCs. (C) 2012 Elsevier Ltd. All rights reserved.