Controllable synthesis of helical, straight, hollow and nitrogen-doped carbon nanofibers and their magnetic properties

Synthesis of Helical Carbon Fibers and Related Materials: A Review on the Past and Recent Developments

“…Therefore, they obtained the purified spiral CNFs. For removing copper nanoparticles (Cu NPs), Li and Xu soaked their CNF samples in concentrated HNO 3 acid for 1 h, separated by centrifugation, and washed with deionized water until the pH of the filtrate was neutral [ 67 ]. Further, the sample was washed with absolute ethanol and dried at 80 °C and purified sample were obtained.…”

“…Experimental parameters such as nature of catalyst [ 73 , 103 ], composition of catalyst [ 104 ], particle size of catalyst [ 68 ], type of carbon source [ 7 ], flow rate of gases [ 55 ], pressure of gases [ 86 ], synthesis temperature [ 67 , 85 ], and active shape (final shape) of the catalysts during synthesis [ 72 , 105 ], are the key parameters, which establish the growth process, structural morphology and microstructure of the as-synthesized HCFs.…”

“…In this study, these various morphologies of CFs were prepared by only changing the N 2 gas flow rate and all other experimental parameters were unchanged. Li and Xu prepared Cu NPs generated from the in situ decomposition of copper acetylacetonate [ 67 ]. These Cu NPs have been used for the selective synthesis of HCNFs, planar CNFs, CNTs, and nitrogen doped ( N -doped) CNFs by adjusting the reaction temperatures or composition of feedstock gas.…”

“…Till date, extensive research has been done on the synthesis [ 8 , 50 , 60 ] and mass production [ 50 , 61 ] of HCFs. The catalysts were usually selected from transition metal particles such as Ni [ 17 , 59 , 62 ], Fe [ 9 , 57 , 63 ], Co [ 64 , 65 ], Cu [ 38 , 66 , 67 , 68 ] and also from their mixture [ 69 ] as well as alloys [ 15 , 70 , 71 , 72 , 73 ]. These transition metal nanoparticles act as nucleation centers for the growth of CFs and catalyze the decomposition of the carbon source [ 5 ].…”

The development, fabrication, and material characterization of polypropylene composites reinforced with carbon nanofiber and hydroxyapatite nanorod hybrid fillers

“…33,34 CNFs are generally synthesized by the catalytic decomposition of hydrocarbons on transition metal catalysts, such as Fe, Co, and Cu nanoparticles, at high temperatures. [35][36][37] Straight and helical CNFs can be selectively prepared by properly monitoring the reaction temperature, feed-gas composition, and the shape of metal nanoparticles. In the latter case, Jian et al reported that spherical Cu nanoparticles favor formation of straight CNFs, while polyhedral or facetted Cu catalysts yield helical CNFs.…”