Full factorial design approach to carbon nanotubes synthesis by CVD method in argon environment

摘要

Whereas meeting product quantity and quality are prime intent in process optimization of materials manufacturing, the application of the more reliable full factorial experiment has not been well-explored in optimization studies of Carbon nanotubes (CNTs) synthesis. In this study, statistical full factorial design of experiment was explored in the parametric studies of CNTs synthesis via acetylene-chemical vapour deposition (CVD). Bimetallic (FeCo) catalyst supported on CaCO 3 was employed for the synthesis of CNTs. The dependence of CNTs yield on the growth time (45/60?min), growth temperature (700/750?°C), acetylene flow rate (150/190?ml/min), and argon flow rate (230/290?ml/min) was investigated in the 2 4 factorial design of experiment. The growth temperature and acetylene flow rate were found to have the most significant effects on the yield of CNTs, and a maximum yield of 170% was obtained at growth conditions of 60?min, 700?°C, 190?ml/min acetylene flow rate, and 230?ml/min argon flow rate. Since acetylene undergoes polymerization or dissolution during non-catalyzed thermal decomposition, the significant effects of temperature and acetylene flow rate as illustrated by the factorial analysis suggests that the selective ability of the FeCo/CaCO 3 catalyst towards CNTs growth in the thermal decomposition of acetylene in CVD was mainly thermodynamics-controlled. Characterization of CNTs samples synthesized at different conditions shows that highest-yield conditions do not guarantee best quality properties. Graphical abstract Display Omitted Highlights ? Full factorial design applied to yield and quality-optimization of CNTs growth conditions in Argon environment. ? Sulphuric acid purification of as-synthesized CNTs when CaCO 3 -supported catalyst is applied to CNTs growth. ? Investigated whether highest-yield conditions guarantee best quality properties of CNTs. ? Effects of growth conditions on CNTs properties by SEM, TEM, XRD, SAED, BET, and EDS.