New empirical potentials between iron nanoparticles and oxide substrates

Interaction of iron catalyst nanoparticles with a substrate may influence nucleation and growth mechanism of carbon nantobutes (CNT) by shifting the melting temperature of the supported iron particles. To account for this effect we have used ab initio calculations to develop empirical potentials between iron nanoparticles and oxide substrates. Simulations have been performed on Fe/Al$_{2}$O$_{3}$ system with Al$_{2}$O$_{3}$ substrate fully relaxed. We have demonstrated that the surface rearrangement effects are significant but can be naturally incorporated into a simple Morse potential, which describes the total nanoparticle-substrate binding. The influence of different substrate surface terminations and positions of Fe layers on the strength of binding are discussed. Potentials for Fe and other oxide substrates are also being evaluated.