| AVS 56th International Symposium & Exhibition | |
| Plasma Science and Technology | Tuesday Sessions |
| Session PS2-TuM |
| Session: | Atmospheric Plasma Processing and Microplasmas |
| Presenter: | R.M. Sankaran, Case Western Reserve University |
| Authors: | W.-H. Chiang, Case Western Reserve University R.M. Sankaran, Case Western Reserve University |
| Correspondent: | Click to Email |
Microplasmas operated at atmospheric pressure in a continuous-flow geometry have tremendous potential for gas-phase nanoparticle synthesis. The non-thermal decomposition of vapor precursors in combination with the limited reaction volume afforded by microplasmas allows the fabrication of narrow dispersions of nanometer-sized particles (< 5 nm) in a single step. We have recently applied this technique to the synthesis of mono- and bimetallic nanoparticles for catalytic carbon nanotube (CNT) growth [1-3]. Dimensionally- and compositionally-controlled nanoparticles are initially prepared in a microplasma from metal-organic precursors such as ferrocene and nickelocene. To catalyze CNTs, acetylene and hydrogen gases are added to the particle flow exiting the microplasma reactor and heated in a tube furnace. Here, we show that the structure of as-grown CNTs is intimately related to the size and composition of the nanocatalysts. Reducing the mean diameter of the nanocatalysts to ~2 nm results in a high-purity of single-walled CNTs in the reactor product (>75 %). At a constant mean particle diameter, compositional tuning of bimetallic nanocatalysts is found to significantly alter the chirality distributions of the collected single-walled CNTs. In this talk, we will present the synthesis methodology, as well as detailed materials characterization of both the nanocatalysts and the CNTs.
1. W-H. Chiang and R. M. Sankaran, “Microplasma synthesis of metal nanoparticles for gas-phase studies of catalyzed carbon nanotube growth,” Appl. Phys. Lett., Vol. 91, 121503 (2007)
2. W-H. Chiang and R. M. Sankaran, “Synergistic effects in bimetallic nanoparticles for low temperature carbon nanotube growth,” Adv. Mater., Vol. 20, 4857 (2008).
3. W-H. Chiang and R. M. Sankaran, “In-flight dimensional tuning of metal nanoparticles by microplasma synthesis for selective production of diameter-controlled carbon nanotubes,” J. Phys. Chem. C, Vol. 112, 17920 (2008).