Selective synthesis of carbon nanomaterials of different structures over KNO3 catalyst

We described a simple route for the generation of pure carbon nanomaterials (CNMs). In the decomposition of acetylene at different temperatures over KNO3 particles, helical carbon nanofibers (HCNFs) and CNFs of low helicity (L-CNFs) are synthesized with high selectivity through the control of pyrolysis temperature. It is found that the size of KNO3 particles is a decisive factor for the growth of CNMs. Since KNO3 is water-soluble, it can be easily removed from the as-synthesized products through steps of water washing, and CNMs can be obtained undamaged in high purity. The approach is simple, inexpensive and environment-benign, and can be adopted for the selective production of high-purity CNMs.