One-step synthesis of highly pure and well-crystallized vertically aligned carbon nanotubes

Emeline Charon (1) , Mathieu Pinault (1) , Martine Mayne-L'Hermite (1) , Cécile Reynaud (1)

1 LEDNA - Laboratoire Edifices Nanométriques

The one-step aerosol-assisted catalytic chemical vapor deposition (CCVD) process, when operated in a H$_2$-based carrier gas, is shown to be effective at an extremely low ferrocene content (0.1wt.% in toluene), which enables to efficiently prepare forests of vertically aligned multiwalled carbon nanotubes (VACNTs) with high purity and good crystalline level. The resulting iron content in VACNT sample is only 0.5wt.% corresponding to a high catalytic yield of 200 while the steady growth rate (20 $\mu$m/min) is maintained at a significant value. The iron content in the sample is found proportional to the ferrocene concentration in the precursor, and when it decreases, a noticeable reduction in the iron encapsulation frequency in the nanotube channel is plainly observed. Lowering the ferrocene concentration generates a reduction in the VACNT number density while the growth rate increases and CNT diameters and crystalline structure remain similar. Such significant purity and crystalline levels involves a high oxidation resistance of the VACNT forest. These results, together with the in-situ continuous growth feature of the one-step aerosol assisted CCVD process, open up towards a new VACNT range made of pure and well-crystallized multi-walled carbon nanotubes, which is of interest for industrial production and commercial applications.

Mots clés: vertically aligned carbon nanotubes; one-step catalytic chemical vapour deposition; iron content; purity; crystallinity; oxidation resistance

Domaines: Matériaux

Emeline Charon, Mathieu Pinault, Martine Mayne-L'Hermite, Cécile Reynaud. One-step synthesis of highly pure and well-crystallized vertically aligned carbon nanotubes. Carbon, 2020, 173, pp.758-768. ⟨10.1016/j.carbon.2020.10.056⟩. ⟨cea-03002425⟩