Electrochemical and Adsorption Properties of Catalytically Formed Carbon Nanofibers

Abstract

After the development of high resolution electron microscopy, the carbon structures of nano dimensions could be explained and investigated in detail and have been used in many fields. These different nanoscale carbon structures have remarkable and unique chemical, physical and mechanical properties. Carbon has long been known to exist as amorphous carbon and in two crystalline allotropic forms: graphite and diamond. Many other carbon based nanomaterials have been developed: fullerenes-discovered by Kroto et al., 1985; carbon nanotubes (CNTs): multi-wall carbon nanotubes (MWCNTs)-recognized discovery attributed to Iijima, 1991 and singlewall carbon nanotubes (SWCNTs) reported at the same time by Iijima & Ichihasi, 1993 and Bethune et al., 1993. The article by Iijima, 1991 which showed that carbon nanotubes were formed during arc-discharge synthesis of C60, has also brought a great interest for carbon nanofibers (CNFs). The history of carbon nanofibers (nanofibers and nanotubes) also named nanofilaments, goes back in the 19th century. A method for growth of catalytically carbon filaments using iron catalyst and a carbon source gas was first patented by Hughes & Chambers, 1889. Radushkevich & Lukyanovich, 1952 obtained hollow graphitic carbon fibers that were 50 nanometers in diameter. They were the first who mentioned carbon nanofibers, but for a long time these nanostructures were of no industrial importance (Peshnev et al., 2007). The interest in the structure of these filaments and their properties emerged in the 1970s with the development of transmission electron microscopy, when the proposal of growth mechanism of Oberlin et al., 1976 was reported. They grew nanometer-scale carbon fibers by chemical vapour deposition (CVD). Tennent, 1987, presented a U.S. patent for graphitic, hollow core fibrils”. The recent increasing scientific and industrial interest in carbon nanofilaments as onedimensional nanomaterials, originates from their unusual application properties and similarities with carbon nanotubes. Carbon nanofibers have been extensively studied: their synthesis and growth mechanism (Oberlin et al., 1976; Tibbetts et al., 1993, 1994; De Jong & Geus, 2000; Helveg et al., 2004; Cui et al., 2004a), their structure (Endo et al., 2002, 2003; Paredes et al., 2005; Eksioglu& Nadarajah, 2006; Lawrence et al., 2008;) and properties (Endo et al., 1993, 1995; Kavan & Dunsch, 2008; Charlier et al., 2008; Damnjanovic et al., 2005). CNFs have been recognized as a very promising material based on their nanostructure and properties. Source: Nanofibers, Book edited by: Ashok Kumar, ISBN 978-953-7619-86-2, pp. 438, February 2010, INTECH, Croatia, downloaded from SCIYO.COM