Large-Scale Synthesis and Characterization of Helically Coiled Carbon Nanotubes by Use of Fe(CO)₅ as Floating Catalyst Precursor

Abstract

Helically shaped multiwalled carbon nanotubes (HCNTs) (diameter 30-80 nm) were obtained as main products in large quantities by co-pyrolysis of Fe(CO) 5 as floating catalyst precursor and pyridine or toluene as carbon source at temperatures above 1000 °C under flow of hydrogen. In contrast, pyrolysis at 700-800 °C yielded only carbon-coated Fe nanoparticles. The HCNTs were characterized by electron microscopy, Raman spectroscopy, and wide-angle X-ray diffraction. The growth mechanism of the HCNTs was discussed on the basis of previously reported models.

Carbon nanotubes and helical carbon nanofibers grown by chemical vapour deposition on C60 fullerene supported Pd nanoparticles

“…Reducing pressure Co particles [14]. Also the co-pyrolysis of pyridine and Fe(CO) 5 as floating catalyst showed excellent result [15] and could even lead to vertically aligned helical carbon nanotubes (VAHCNTs) [16]. Sulfur has been shown to play a key role in enabling different catalyst, that under normal conditions are used for the growth of straight structures, to grow helical structures [11,17].…”

Large‐Scale Synthesis, Annealing, Purification, and Magnetic Properties of Crystalline Helical Carbon Nanotubes with Symmetrical Structures

“…[4] These materials can be synthesized as major products in the thermal reduction of ethyl ether over Zn in a stainless-steel autoclave at 700°C, [5] as well as in the co-pyrolysis of Fe(CO) 5 (as a floating catalyst precursor) and pyridine or toluene (as the carbon source) at temperatures above 1000°C in H 2 . [6] The large-scale synthesis of perpendicularly aligned HCNTs has been successfully achieved by the co-pyrolysis of Fe(CO) 5 and pyridine at 900-1100°C in a mixed flow of Ar and H 2 . [7] To the best of our knowledge, most of the published work on HCNTs is focused on CNTs with a single helix, and there has been very little effort in studying double HCNTs with symmetric structures.…”

Synthesis of Multiwalled Carbon Nanotubes by Catalytic Combustion of Polypropylene

“…Catalytic decomposition of hydrocarbons is a promising means to produce carbon nanotubes on a large scale. [7,8] Recently the catalytic flame synthesis of CNTs was reported. [9][10][11] This method has several advantages, for example, it is inherently easier to scale up relative to other production methods that employ electricity.…”