Continuous synthesis of multiwalled carbon nanotubes from xylene using the swirled floating catalyst chemical vapor depo
- PDF / 238,615 Bytes
- 5 Pages / 584.957 x 782.986 pts Page_size
- 66 Downloads / 282 Views
Sunny E. Iyuke, and Geoffrey S. Simate School of Chemical and Metallurgical Engineering, University of Witwatersrand, Johannesburg, Wits 2050, South Africa
Emmanuel I. Unuabonah College of Natural Sciences, Department of Chemical Sciences, Redeemer’s University, Redemption City, Mowe, Nigeria
Graham Bathgate, George Matthews, and John D. Cluett School of Chemical and Metallurgical Engineering, University of Witwatersrand, Johannesburg, Wits 2050, South Africa (Received 7 June 2010; accepted 13 October 2010)
This work reports the continuous and large-scale production of multiwalled carbon nanotubes (MWCNTs) from xylene/ferrocene in a swirled floating catalyst chemical vapor deposition reactor using argon as the carrier gas. The concentration of ferrocene used was 0.01 g/mL of xylene. In every run, 50-mL xylene gas was used together with xylene/ferrocene mixture injected into the reactor by means of a burette. The MWCNTs produced were characterized using the transmission electron microscopy (TEM) and Raman spectra. TEM analysis showed a poor production rate at 850 °C and a good production in the range of 900–1000 °C with optimal production rate at 950 °C. Furthermore, xylene/ferrocene mixture produced more MWCNTs at 950 °C with H:Ar (1:7) as the carrier gas. The diameters of the MWCNTs in the temperatures studied ranged from 15 to 95 nm with wall thicknesses between 0.5 and 0.8 nm. I. INTRODUCTION
Iijima,1 a Japanese scientist discovered new carbon structures; namely, carbon nanotubes (CNTs), which are made of either single- or multilayered graphite chip coils. The C–C covalent bonds in the CNTs are the most stable chemical bonds in nature. As a result, CNTs have high strength, great toughness, high thermal stability, low density, and are resistant to strong acid and alkali.2,3 Furthermore, because a large number of unpaired electrons move along the wall, CNTs have both metallic conductivity and semiconductor properties.4 Research on the preparation and properties of CNTs as well as their applications in various fields has become an important subject, and has made remarkable progress. Several techniques such as the arc discharge, laser ablation, and chemical vapor deposition (CVD) have been used in the production of CNTs.5,6 However, only the CVD technique has gained significant recognition and application because of its easy operation and the possibility of continuous production of CNTs depending on the Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2010.69 J. Mater. Res., Vol. 26, No. 5, Mar 14, 2011
http://journals.cambridge.org
II. MATERIALS AND METHOD
The paraphernalia in Fig. 1 illustrates the setup of the SFCCVD. It is made of a vertical silica plug flow reactor inside a furnace. Gases flow into the reactor with the aid of
a)
640
carbon source.7–9 Various modes of the CVD technique that exist include the microwave CVD, horizontal fixed bed catalytic CVD, and the rotary tube. Recently, we introduced the swirled floating catalyst chemical vapor deposition (SFCCV
Data Loading...
