Abstract
In this paper, we investigate the effect of chlorine as a growth promoter in the synthesis of multiwalled carbon nanotubes (MWCNTs). We find that the addition of chlorine gas to the chemical vapor deposition process reduces the amount of amorphous carbon deposited on the MWCNT surfaces and results in a longer catalyst lifetime. By using optimum growth parameters, the catalyst remains active for 75 min. Moreover, the growth rate is also relatively high resulting in the maximum CNT array height of 3.5 mm. The MWCNT arrays grown with and without chlorine are compared.