Viscous state effect on the activity of Fe nanocatalysts.

Cervantes-Sodi, F and McNicholas, TP and Simmons, JG and Liu, J and Csányi, G and Ferrari, AC and Curtarolo, S (2010) Viscous state effect on the activity of Fe nanocatalysts. ACS Nano, 4. pp. 6950-6956.

Abstract

Many applications of nanotubes and nanowires require controlled bottom-up engineering of these nanostructures. In catalytic chemical vapor deposition, the thermo-kinetic state of the nanocatalysts near the melting point is one of the factors ruling the morphology of the grown structures. We present theoretical and experimental evidence of a viscous state for nanoparticles near their melting point. The state exists over a temperature range scaling inversely with the catalyst size, resulting in enhanced self-diffusion and fluidity across the solid-liquid transformation. The overall effect of this phenomenon on the growth of nanotubes is that, for a given temperature, smaller nanoparticles have a larger reaction rate than larger catalysts.