Synthesis and Study of Carbon Nanotubes by the Spray Pyrolysis Method Using Different Carbon Sources.
- PDF / 2,176,936 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 32 Downloads / 200 Views
Synthesis and Study of Carbon Nanotubes by the Spray Pyrolysis Method Using Different Carbon Sources. Beatriz Ortega Garcia1, Oxana Kharissova1, Francisco Servando Aguirre-Tostado2, Rasika Dias3 1
Universidad Autónoma de Nuevo León (UANL), FCFM, Monterrey, N.L., México. Centro de Investigación en Materiales Avanzados (CIMAV), Monterrey, N.L., México. 3 University of Texas at Arlington, Department of Chemistry and Biochemistry, Arlington, TX, USA 2
ABSTRACT According to the reports of Z.E. Horvath et al [1] and Liu Yun-quan et al [5], carbon nanotubes can be synthesized by spray pyrolysis from different carbon sources (n-pentane, nhexane, n-heptane, cyclohexane, toluene and acrylonitrile) and several metallocene catalysts (ferrocene, cobaltocene and nickelocene). This paper describes two different existing methods for growth of carbon nanotubes and the influence of applied parameters (oven temperature, synthesis time, catalyst concentration, carrier gas flow and solution flow) on the CNT's morphology. Also, a possible influence of number of carbons in carbon sources and structures of their compounds (linear or aromatic) on properties of formed carbon nanotubes. Transmission Electron Microscopy (TEM), Infrared Spectroscopy (FTIR) and Raman spectroscopy were applied for characterization of obtained materials. INTRODUCTION Carbon nanotubes, a nanomaterial well-known since the 90's due to its excellent mechanical, electrical and thermal properties, are divided into two types, single-walled (SWCNTs) and multi-walled (MWCNTs). Both nanotube types are used for many applications and can be synthesized by different methods. Z.E. Horváth et al. [1] compared electric arc and spray pyrolysis methods and concluded that the growth of multiwall carbon nanotubes leads to more pure product using spray pyrolysis method. Different catalysts can be used in this method, such as ferrocene, dimethylferrocene, diethylferrocene, acetylferrocene [2], ferrocene, cobaltocene, nickelocene and their mixtures [1]. Ferrocene is still the one most compatible with the afore mentioned carbon sources and it is one of the most widely used because of its low cost. There are two different theories for growth of carbon nanotubes, as can be seen in Figure 1; their growth depends on various parameters [3]. C. Singh et al. [4] carried out a study for production of controlled architectures of aligned carbon nanotubes, changing such parameters as oven temperature, catalyst concentration, synthesis time, gas flow and hydrogen concentration. They found that growth temperature can vary between 550 and 940°C and concluded that the maximum yield is obtained at 760°C; on this basis, we decided to fix 800°C as predetermined oven temperature. Discussing the synthesis time, we need to comment that this parameter has a relation with the precursor solution flow, meanwhile the gas flow has a relation with oven temperature. When decreasing the precursor solution flow, the synthesis time should be increased for obtaining a better quality of material. We need to pay attenti
Data Loading...
