Growth and Annealing Properties of Carbon Nanofibers on Carbon Black By Using Chemical Vapour Deposition

Abstract

Various nanocarbon materials, such as fullerenes [1], carbon nanotubes (CNTs) [2], graphene [3], carbon nanofibers (CNFs) [4,5,6] and carbon nanospheres [7], have potential applications in next-generation electrical [8,9] and electrochemical devices [10–13] due to their excellent physical (e.g., crystal, semi-crystal, amorphous structures) and chemical properties (e.g., high specific surface area, large pore volume). The nanostructures depend on the catalysts, hydrocarbon sources, temperature, etc., and the growth mechanism has been extensively studied [5,6,14]. Nanocarbon composite materials are expected to exhibit synergistic effects not only in the bulk but also in composites. Amorphous carbon blacks (CBs), such as Vulcan XC-72R (Cabot Co.) and Ketjen (Akzonobel, Lion speciality chemicals Co., Ltd.), are used widely as electrode supporting nanocarbon materials due to their excellent electronic conducting properties and high specific surface areas. Recently, for renewable energy conversion technology, high performance nanocarbon materials are still required. In this study, we investigated the growth and annealing properties of CNFs on CB by using chemical vapour deposition with a Ni catalyst. The as-grown CNF-CB composites were annealed at different temperatures. The crystallinity and thermal properties of the CNF-CB composite increased with an increase in the annealing temperature. The micropore and mesopore areas of the CNF-CB composites decreased and increased, respectively, as compared to those of CB only. The CNF-CB composite annealed at 1600 °C had a higher current density than only CB did, as determined by using cyclic voltammetry (CV). The CNF-CB composites should be extremely useful in various energy applications, such as fuel cells, capacitors, and batteries. Acknowledgements This work was partially supported by the MEXT program for development of environmental technology using nanotechnology.