Bimetallic Catalysts for the Efficient Growth of SWNTs on Surfaces

Bimetallic catalysts such as Fe\Ru and Fe\Pt in the size range of 0.5-3 nm are currently being considered for the efficient growth of single-walled carbon nanotubes (SWNTs) on flat surfaces. It has been shown possible, by using chemical reduction under microwave irradiation and poly(N-vinyl-2-pyrrolidone) (PVP) as a protective agent, to produce uniform Fe\Ru and Fe\Pt bimetallic nanoparticles. Energy-dispersive X-ray analysis (EDAX) confirmed the presence of Fe and Ru or Fe and Pt, and high-resolution transmission electron microscopy (HRTEM) showed that they were highly crystalline. The nanoparticles were subsequently used as catalysts for the surface growth of SWNTs by chemical vapor deposition (CVD). When compared with single-component catalysts such as Fe, Ru, and Pt of similar size, bimetallic catalysts Fe\Ru and Fe\Pt produced at least 200% more SWNTs, as measured by atomic force microcopy (AFM). Possible reasons for the high efficiency of bimetallic catalysts are discussed in this study