Electrified synthesis of small-diameter single-walled carbon nanotubes via plasma-catalytic pyrolysis of methane

Synthesis of small-diameter (ca. 1 nm) single-walled carbon nanotubes (SWCNTs) is rare due to the difficulty in establishing appropriate catalysts and environments that favor the generation of such species. However, because of their auspicious and structure-tunable electrical and optical properties, this goal remains at the focal point of numerous researchers. The development of a low-cost technique to create such materials could eliminate the main bottleneck hindering their widespread application. In this work, this objective was ultimately achieved by means of the Plasma-Catalytic Pyrolysis (PCP) process. The application of a DC water-stabilized plasma hybrid (WSP-H) torch within an entrained-flow reactor facilitated the breakdown of methane in the presence of an FeO micropowder (50 µm) catalyst. Consequently, high-quality SWCNTs and hydrogen were produced at a relatively large scale. Characterization of the resulting SWCNTs by microscopy and spectroscopy confirmed that the produced SWCNTs exhibited a large degree of structural perfection.