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

We present the use of Selenium (Se) and Tellurium (Te) as promoters in the growth of carbon nanotubes (CNTs) by chemical vapor deposition (CVD) and direct spinning from the gas phase into a continuous macroscopic fiber. At low Se concentrations (0.0018 at.%) the tubes are of single-walled type and predominantly armchair chiral angle. Increasing Se content produces an increase in CNT diameter and their self-collapse or even self-folding. The stability of these morphologies is compared by molecular dynamics simulations. These results add Se and Te to the list of promoters currently used for CNT growth (Sulfur (S), Oxygen (O)). Even at very small concentrations, these elements dominate the catalyst surface, where they contribute to the lowering of the surface tension of molten Iron (Fe), the catalytic decomposition of the Carbon (C) source and reconstruction of graphitic layers. Preliminary fiber specific strength is up to 0.9 GPa SG−1 and toughness of ∼80 J g−1, resulting in a ballistic protection figure of merit of 760 m s−1.

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