Ad Astra Awards
Ad Astra Journal
Science library
White book
University rankings
Who's who
Publications
Theses and dissertations
Ad Astra association
 
Press releases
News
Events
Funding opportunities
 
Login
Registration
 
>> Românã
 
   
 

Yuan Chen, Li Wei, Bo Wang, Sangyun Lim, Dragos Ciuparu, Ming Zheng, Jia Chen, Codruta Zoican, Yanhui Yang. Gary L. Haller, Lisa D. Pfefferle. Low-Defect, Purified, Narrowly (n, m)-Dispersed Single-Walled Carbon Nanotubes Grown from Cobalt-Incorporated MCM-41. ACS Nano, 1(4), pp. 327-336, 2007.

Abstract: A mild, four-step purification procedure using NaOH reflux, HCl wash, and oxidation by 4 mol % molecular oxygen at 500 C was developed to purify single-walled carbon nanotubes (SWCNTs) with narrow semiconducting (n,m) distribution produced from cobalt-incorporated MCM-41 (Co-MCM-41) in order to obtain bulk low-defect-density nanotubes. Three key features of Co-MCM-41 allow this mild purification technique: (1) ultrathin silica walls versus dense silica or other crystalline oxide supports are soluble in dilute NaOH aqueous solution, which avoids the damage to SWCNTs usually caused by using HF treatment to remove catalytic supports; (2) the small metallic particles are easily dissolved in HCl, a significantly milder chemical treatment compared to HF or HNO3; (3) the high selectivity to SWCNTs with negligible multiwalled carbon nanotubes or graphite, which facilitates the removal of undesired carbon species by selective oxidation. The effectiveness of this purification procedure was evaluated by high-resolution transmission electron microscopy, scanning electron microscopy, Raman, UV-vis−NIR, and fluorescence spectroscopy, solution redox chemistry on fractionated (6,5) tubes, and SWCNT-based field effect transistor device performance. The results demonstrate that Co-MCM-41 catalyst not only provides tubes with narrow semiconducting (n,m) distribution but also allows a mild purification procedure and, therefore, produces SWCNTs with fewer defects.

Keywords: single wall carbon nanotubes, catalytic chemical vapor deposition, coblat catalyst, MCM-41

URL: http://dx.doi.org/10.1021/nn700106c

Posted by Dragos Ciuparu

Back

   
© Ad Astra 2001-2013