Effects of the amount of ferrocene and ammonium chloride on the diameter distribution of hollow carbon spheres synthesized in high-pressure argon

The effects of the amount of the ferrocene and ammonium chloride on the diameter distribution of hollow carbon spheres (HCSs) prepared in high-pressure argon were investigated. The morphology and diameter distribution of the HCSs were characterized by field-emission scanning electron microscopy which showed that the diameter of most HCSs ranges from 1 to 10 μm. The median diameter increases with the total amount of the reactants with the same weight ratio of ferrocene to ammonium chloride. When excess ammonium chloride is used, HCSs with a bimodal diameter distribution are prepared; however, the median diameter is almost the same. It is proposed that the aggregation of iron particles and liquid Fe(NH3)2Cl2 templates, and the transformation of the iron amine complexes, in the process mainly influence the diameter distribution of the HCSs.