Catalytic Effects in the Large-scale Synthesis of Carbon Nanotubes

Abstract

Carbon nanotubes have potential applications in a variety of fields, such as composites, field-emission displays, elec- trodes, gas adsorbent, and catalyst supports. For putting these applications into industry, it is very important to establish the mass production of nanotubes. Here, we introduce our recent progress on the large-scale synthesis of carbon nanotubes, in particular, single-wall carbon nanotubes (SWNTs), based on the gas-phase flow reaction. By spraying the Co-Mo nanopar- ticles dissolved in toluene to the vertical furnace, we succeeded in selectively obtaining SWNTs and multi-wall carbon nanotubes (MWNTs). It was found that the structure and quality of nanotubes depend on the concentration of the thiophene additives, the hydrogen gas flow rate, and the injection rate of the colloidal solution. The growth mechanism of SWNTs andMWNTs are discussed in terms of catalytic effects. Other large-scale synthetic methods for SWNTs, such as high pres- sure CO disproportionation (HiPco) and the supported catalysts-based fluidized bed reactions are also introduced.