Synthesis of coiled carbon nanofibers by Cu-Ni alloy nanoparticles catalyzed decomposition of acetylene at the low temperature of 241 °C

Helical carbon nanofibers with a symmetric growth mode were synthesized by the catalytic decomposition of acetylene at 241 °C with Cu-Ni alloy nanoparticles prepared by hydrogen-arc plasma method as a catalyst. We obtained a high yield of coiled nanofibers. The morphology and microstructure of the coiled carbon nanofibers was examined in detail. We found that there were only two helical fibers symmetrically grown over a single Cu-Ni alloy nanoparticle, which was faceted with a regular shape (quadrangular, triangular, oblong and rhombus). The two coiled fibers have different coiled chirality, but have identical cycle number, coil diameter, coil length and fiber diameter. The angles between the two helical fibers grown on a single catalyst nanoparticles were different.