Synthesis of bimetallic nanoparticles and their application to growth of multiwalled carbon nanotube forest.

We synthesized bimetallic nanoparticles and used them to grow CNTs with an atmospheric-pressure plasma-enhanced chemical vapor deposition system. FePt and FeCo bimetallic nanoparticles were synthesized by the bottom-up high-temperature polyol process using a simple centrifugal method. The diameter of synthesized nanoparticles ranged from 2 to 5 nm with high uniformity, as measured with a transmission electron microscope. The CNTs synthesis was carried out on bimetallic nanoparticles as a catalyst using acetylene as a carbon source gas. The CNT forests grown exhibited a maximum height of 96 Am, which is relatively high compared with other growth technologies. A forest of highly pure multiwalled CNTs with diameters of 10-20 nm was successfully synthesized on a bimetallic nanoparticle catalyzed substrate. As the growth temperature increased, the quality of CNTs improved remarkably, indicating that the graphitization could be controlled by varying the growth temperature. Furthermore, the oxygen plasma pre-treatment of dispersed bimetallic nanoparticles before CNTs growth could contribute to the production of highly pure CNTs. By TEM measurements, we observed that pure multiwall CNTs without defects or amorphous carbon could be synthesized.