Study of the Thermal Stability of Supported Catalytic Nanoparticles for the Growth of Single-Walled Carbon Nanotubes with Narrow Diameter Distribution by Chemical Vapor Deposition of Methane

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• 作者：Pierre Petit ; Diana Salem ; Maoshuai He ; Matthieu Paillet ; Romain Parret ; Jean-Louis Sauvajol ; Ahmed Zahab
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 15, 2012
• 年：2012
• 卷：116
• 期：45
• 页码：24123-24129
• 全文大小：379K
• 年卷期：v.116,no.45(November 15, 2012)
• ISSN：1932-7455

文摘

The thermal stability of catalytic precursors is of major importance for the synthesis of single-walled carbon nanotubes (SWNTs) with narrow diameter distributions by chemical vapor deposition at high temperature. We report a study of the thermal stability of iron (Fe) and iron oxide (Fe₂O₃) nanoparticles with narrow size distribution grown onto Si/SiO₂ hydroxylated flat substrates. Whereas the Fe₂O₃ nanoparticles are thermally stable up to 900 掳C, above their reducing temperature of 700 掳C, the size distribution of Fe nanoparticles increases and broadens. An accurate analysis of atomic force microscopy data shows that this instability is due to a diffusion鈥揷oalescence mechanism, ruling out a possible Ostwald鈥檚 ripening mechanism. The origin of this behavior is attributed to the dewetting of the nanoparticles. Using the thermally stable oxide nanoparticles as catalytic precursors, SWNTs can be successfully grown using a methane鈥揾ydrogen mixed gas. Statistical analysis of the SWNTs Raman radial breathing modes measured using four excitation wavelengths indicates that the diameter distribution of the nanotubes is centered at 1.3 卤 0.03 nm with a narrow full width at half-maximum of 0.3 卤 0.05 nm. The analysis of our results compared with other results recently published suggests that the metal鈥搒urface interaction could play a key role in the catalytic decomposition of methane and in the growth of SWNTs.