Optimization of Experimental Conditions for Fabrication of Carbon Nanotubes Based onTaguchi obust Design Method

Carbon nanotube, a new structure of carbon element, is composed of graphene sheets rolled into closed concentric cylinders with diameter of the order of nanometers and length of micrometers. Liquid arc discharge was used for fabrication of carbon nanotubes, and subsequently a modified acid treatment method applied for purification stage. A statistical design of experimental (DOE) (Taguchi method with L16 orthogonal array robust (OA) design and Qualitek-4 software) was implemented in this work to optimize the process. Voltage, current, catalyst type and plasma were considered as process parameters to be optimized. As the result of taguchi analysis in this study, voltage and catalyst were the most influencing parameters on the yield production of carbon nanotubes (~4.121 mg min-1 purred CNTs). The maximum product yield of CNTs were obtained at voltage of 25, LiCl (o.25 M) as a salt in solution, Ni/Mo as a co-catalyst and the catalyst ratio of. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to study the morphology of these carbon nanotubes.