AVS 58th Annual International Symposium and Exhibition
    Graphene and Related Materials Focus Topic Tuesday Sessions
       Session GR-TuP

Paper GR-TuP3
Synthesis of Carbon Nanoballs, Covered by CNTs with Metallic Conductivity

Tuesday, November 1, 2011, 6:00 pm, Room East Exhibit Hall

Session: Graphene and Related Materials Focus Topic Poster Session
Presenter: Kazuyoshi Ohno, Nagoya University, Japan
Authors: K. Ohno, Nagoya University, Japan
N. Zettsu, Nagoya University, Japan
T. Ueno, Nagoya University, Japan
O. Takai, Nagoya University, Japan
N. Saito, Nagoya University, Japan
Correspondent: Click to Email
Carbon nanostructures, due to their unique electronic and extraordinary mechanical properties, have been receiving much attention for a wide variety of applications. Especially, highly-conductive carbon nanostructures is a promising candidate supports for heterogeneous catalysts, for use in fuel cells and in metal-air sources of current. Synergetic interaction of the catalyst-nanoparticles with carbon nanostructures exhibits better catalytic parameters than application of carbonaceous materials.

Very recently, we demonstrated a fabrication of platinum catalysts supported on carbon nanoballs (CNBs), as well as characterization of their electrochemical activities (Saito et al., J. Vac. Sci. Technol. A, 27(4) pp.826-830). Originally-developed CNB is a highly crystallized nanosized carbon powder with spherical shape. The CNBs can be synthesized by thermal decomposition of ethylene and hydrogens under argon stream. Diameter of CNB can be tuned from 200 to 700nm by changing the mixing ratio of H2. Platinum nanoparticles were densely loaded on the CNBs surface under modified solution plasma processing of CNBs and Pt ions with stabilizing agents. We obtained 1.6-fold incr ease in the electrochemical activity of Pt/CNBs system (0.26cm2/mg) compared with that of conventionally-used Pt/C system (0.16cm2/mg).

In this work, we propose newly developed CNBs, covered by carbon nanotubes (CNTs) with metallic conductivity in order to reduce contact resistance between neighboring CNBs in electrodes. We grew CNTs from various shaped Fe, Ni nanocrystals deposited onto an individual CNB, and subsequently decorated the surface of the CNBs with Pt nanoparticles as a catalyst by using solution plasma processing. The ratio of metallic to semiconducting CNTs of our all products was evaluated by Raman spectroscopy.