Group 16 elements control the synthesis of continuous fibers of carbon nanotubes

Carbon nanotube fibers with martensite and austenite Fe residual catalyst: room temperature ferromagnetism and implications for CVD growth

“…FC-ZFC curves further show that only S-CNT fibers present a clear superparamagnetic behavior below 300 K (T B = 140K), which is a consequence of the smaller size of residual catalyst nanparticles compared to those produced using Se. This is consistent with previous observations on the size and shape of catalyst nanoparticles in Se assisted CNT fiber [20] and highlights the role of the promoter in controlling C solubility, catalytic activity and catalyst particle coarsening through coalescence.…”

“…CNT fibers (CNTfs) were synthesized by direct spinning of CNTs from the gas phase by floating catalyst CVD [18] using butanol as C source, ferrocene as Fe catalyst and S (S-CNTf) or Se (Se-CNTf) as promoters. The concentration of precursors during fiber production was adjusted so as to produce CNTs of predominantly single-wall (SWCNTs) or multi-wall (MWCNTs) of few layers (<5) [19,20]. Thus, four types of fibers were produced and analyzed: SWCNT from S, SWCNT from Se, MWCNT from S and MWCNT from Se (Table 1).…”

Inherent predominance of high chiral angle metallic carbon nanotubes in continuous fibers grown from a molten catalyst

“…The samples analyzed included fiber from different batches to ensure reproducibility of the CVD reaction conditions. Selected samples were produced using Se as promoter, 36 or toluene as the C source. SEM and ion milling were carried out with an FIB-FEGSEM Helios NanoLab 600i (FEI) at 30 kV.…”

The Dependence of CNT Aerogel Synthesis on Sulfur-driven Catalyst Nucleation Processes and a Critical Catalyst Particle Mass Concentration

“…The dramatic improvements provided by bulk CNT materials in diverse fields such as high strength and toughness composites 4 – 7 , electrically conductive 8 and thermally conductive materials 9 – 12 , and electromagnetic shielding 13 coupled with the facile synthesis route, means applications research continues to expand worldwide at an increasing rate with new groups joining the field 14 – 17 . There are many chemical routes to gas phase synthesized CNT aerogels, in the following referred to as CNT aerogels, based around hydrocarbons, aromatic hydrocarbons or alcohols 18 but all share the common features of a catalyst precursor (typically ferrocene) and a S or elemental group 16 containing compound 19 , essential for aerogel synthesis.…”