Morphological Evolution of Fe鈥揗o Bimetallic Catalysts for Diameter and Density Modulation of Vertically Aligned Carbon Nanotubes

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• 作者：Seul Ki Youn ; Hyung Gyu Park
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：September 12, 2013
• 年：2013
• 卷：117
• 期：36
• 页码：18657-18665
• 全文大小：495K
• 年卷期：v.117,no.36(September 12, 2013)
• ISSN：1932-7455

文摘

Fe鈥揗o bimetallic catalyst is a promising candidate for achieving efficient growth and fine structures of vertically aligned carbon nanotubes (VA-CNTs) by catalytic chemical vapor deposition (CVD). Understanding the surface morphological evolution of a bilayer metal film and accompanied changes in the resultant CNT structure is a key to modulating the VA-CNT growth. We correlate the growth rates and individual CNT structures with the Fe鈥揗o catalyst morphological evolution. At CVD conditions, the layered bimetallic films evolve into entirely different ensembles of polydispersed nanoparticles depending on the ratio and stacking order between Fe and Mo. Specifically, Fe-on-Mo type nanofilms develop to denser and smaller nanoparticles with more pronounced bimodality in size than do Mo-on-Fe type nanofilms, leading to better alignment and unique diameter distribution of resultant CNTs. Also, the decrease in the catalytic activity of Mo-rich Fe鈥揗o nanoparticles can contribute to the diameter, alignment, and density modulation of VA-CNTs.