Comprehensive Density Functional and Kinetic Monte Carlo Study of CO Hydrogenation on a Well-Defined Ni/CeO Model Catalyst: Role of Eley-Rideal Reactions.

A detailed multiscale study of the mechanism of CO hydrogenation on a well-defined Ni/CeO model catalyst is reported that couples periodic density functional theory (DFT) calculations with kinetic Monte Carlo (kMC) simulations. The study includes an analysis of the role of Eley-Rideal elementary steps for the water formation step, which are usually neglected on the overall picture of the mechanism, catalytic activity, and selectivity. The DFT calculations for the chosen model consisting of a Ni cluster supported on CeO (111) show large enough adsorption energies along with low energy barriers that suggest this catalyst to be a good option for high selective CO methanation.

Structural, electronic, and magnetic properties of Ni nanoparticles supported on the TiC(001) surface.

Metals supported on transition metal carbides are known to exhibit good catalytic activity and selectivity, which is interpreted in terms of electron polarization induced by the support. In the present work we go one step further and investigate the effect that a titanium carbide (TiC) support has on the structural, electronic, and magnetic properties of a series of Ni nanoparticles of increasing size exhibiting a two- or three-dimensional morphology. The obtained results show that three-dimensional nanoparticles are more stable and easier to form than their homologous two-dimensional counterparts.