Optimization of CCVD synthesis conditions for single-wall carbon nanotubes by statistical design of experiments (DoE)

摘要

We report the successful optimization of single-wall carbon nanotube (SWCNT) synthesis by catalytic chemical vapor deposition (CCVD) on FeMo/MgO catalyst using acetylene as carbon source. Taking a starting parameter set from the literature we optimized seven (catalyst composition, catalyst amount, reaction temperature, reaction time, preheating time, C_2H_2 volumetric flow rate, inert gas volumetric flow rate) factors to our local experimental system by relying on statistical design of experiments (DoE). Performance was assessed using two quantitative descriptors: mass of carbonaceous material formed and SWCNT content afcalculated from FT-Raman spectra. The parameter space was first screened for important factors using a 2~(7-4)m fractional factorial design, then the response surface defined by the three most significant parameters was obtained from Box-Behnken design and the optimal parameter set was found. The superiority of the DoE method over the conventional COST (change one separate factor at a time) approach is shown by the fact that we were able to optimize seven individual factors with only 21+2 runs. The described method can readily be used to swiftly adapt a literature-based CCVD process to the local instrumentation of any laboratory.