Application of SiO2 spheres in the synthesis of coiled carbon nanofibers with high purity

Abstract During a chemical vapor deposition synthesis process of carbon fibers, copper-based catalyst particles tend to aggregate into larger secondary particles and lead to the growth of straight carbon fibers with large diameters. The introduction of silicon dioxide spheres can provide enough sites to uniformly disperse catalyst particles and prevent the agglomeration of adjacent catalyst particles, and thereby coiled carbon nanofibers are synthesized using common copper-based salts without special pretreatment, including copper chloride, copper nitrate and copper sulfate. The size of copper-based catalyst particles is about 10 to 15 nm. Also, effects of the concentration of copper-based salt catalyst and reaction temperature on coiled carbon fibers are investigated. Furthermore, silicon dioxide spheres can be removed easily by NaOH solution to obtain coiled carbon nanofibers.