Organometallic catalysts for the synthesis of carbon nanostructures

Carbon nanofibers (CNFs) and carbon nanotubes (CNTs) [1] with their interesting structural, chemical, electronic and mechanical properties attracted the attention of many researchers all over the world. Many methods have been proposed for CNF and CNT production, such as, chemical vapor deposition (CVD) [2] electrospinning followed by thermal processing [3], laser ablation process [4] and arc discharging [5]. CVD was preferred in this study due to its scalability and potentially low cost, as well as the structural perfection can be achieved by this method. The most important factor is to control of the metal catalyst; Gaining an understanding of the chemistry involved in the catalyst and nanotube/nanofiber growth process is critical to enable materials scale-up by CVD and increase the quality of the product. Our aim is to understand the structural and chemical effects of the catalyst on CVD process. Thus, transition metal catalysts (Cr, Mn, Fe, Co, Ni, Cu, Zn) were synthesized by different methods in the ornanometallic form and the performance of those catalysts during the catalytic growth of carbon nanofiber and nanotubes was determined. The electronic properties, microstructure, surface properties, and stability of the catalysts were investigated in order to relate them to the properties of the final carbon structure. Figure 1 shows the SEM micrographs of organometallic catalyst and the carbon nanosturecture obtained by using acetylene as the carbon source.