Evolution of the Rhodium Colloid Supported on Graphite Studied by Atomic Force Microscopy in the Tapping Mode

Rhodium colloid stabilized by trioctylamine and deposited on a highly oriented pyrolitic graphite was studied by atomic force microscopy in the tapping mode. Most of the intact colloid particles are found to be agglomerated via two-dimensional islands or sphere-shaped clusters attached to the steps of the graphite surface. No particle sintering occurs after thermal treatments in vacuo at 100−550 °C. Oxidation at 550 °C leads to sintering of the particles contacting with the carbon support but not within spherical 3D-aggregates. In addition, AFM images show the gasification trails following the Rh particles on graphite. Data indicate a strong colloid−support interaction under oxidative conditions.