Ab Initio Molecular Dynamics Simulation of the Dissociation of Ethanol on a Nickel Cluster: Understanding the Initial Stage of Metal-Catalyzed Growth of Carbon Nanotubes

The dissociation of ethanol molecules on a nickel cluster was investigated by ab initio molecular dynamics and nudged-elastic-band (NEB) simulations to discuss the initial stage of metal-catalyzed growth of carbon nanotubes via alcohol catalytic chemical vapor deposition. Both C-C and C-O bonds in ethanol molecules are dissociated on the nickel cluster, which is followed by the formation of various reaction products such as hydrogen atoms and molecules, carbon monoxide, oxygen atoms, water, ethylene, methane, and their fragments. Moreover, the NEB analysis revealed that the activation energy for C-H bond dissociation in the fragment molecules on the nickel cluster is just approximately one-eighth of the bond-dissociation energy of the corresponding C-H bond without the influence of the nickel cluster. This confirms that the nickel cluster acts as the activator of the dissociation process of carbon-source molecules by reducing the activation energy.