Taguchi-optimised production of MWCNT-based hybrid nanocomposites by catalytic route

The production of multi-walled C nanotubes (MWCNTs) and MWCNT-based nanohybrids by chemical vapour deposition (CVD) of isobutane is optimised by Taguchi’s robust design method. Processing conditions (calcination at 450–750°C and reduction at 500–700°C) and support material (Al2O3, MgO or Na+-K10) of the Fe-catalyst and synthesis temperature (500–700°C) are assumed to be factors controlling yield (YC) of the catalytic process and graphitisation degree of the grown MWCNTs, as measured by the average crystallite size (LC) inferred from Raman spectroscopy. Poor YC (<9gMWCNTs/gFe) and small LC (~15nm) are obtained, on average, in CVD experiments before optimisation. An outstanding improvement is achieved (YC=51gMWCNTs/gFe and LC=45nm) upon optimised conditions.