Morphology optimization of CCVD-synthesized multiwall carbon nanotubes, usingstatistical design of experiments

Abstract

The possibility of optimization of morphological features of multiwall carbon nanotubes(MWCNTs) using the statistical design of experiments (DoE) is investigated. In this study,MWCNTs were synthesized using a catalytic chemical vapour deposition (CCVD) methodin a horizontal reactor using acetylene as the carbon source. The effects of six synthesisparameters (synthesis time, synthesis temperature, catalyst mass, reduction time,acetylene flow rate and hydrogen flow rate) on the average diameter and meanrectilinear length (MRL) of carbon nanotubes were examined using fractional-factorialdesign (FFD) coupled with response surface methodology (RSM). Using a2III6–3 FFD, the main effects of reaction temperature, hydrogen flow rate and chemicalreduction time were concluded to be the key factors influencing the diameter andMRL of MWCNTs; then Box–Behnken design (BBD) was exploited to create aresponse surface from the main factors. The total number of required runs is26: 8 runs are for FFD parameter screening, 17 runs are for the response surfaceobtained by the BBD, and the final run is used to confirm the predicted results.