Metal Oxide Surfaces

I employ (Hybrid) Density Functional Theory (DFT) and Interatomic Potential (IP) Techniques to calculate the stability of clean and defective (steps, dimer vacancies, grooves) surfaces, which can be compared directly with experiment. Moreover, the electronic properties of those surfaces (e.g. ionisation potential, electron affinity, band bending across the surface and band gap) are calculated to help in the understanding of the material’s behaviour.

Surface band bending of ZnO

Interatomic Potentials Development

Global optimisation techniques are a very powerful tool in the search of the lowest energy structure for a particular system; however, these techniques can be very expensive computationally using the wrong approach. Usually, ab initio methods are not suitable for these tasks when the number of combinations is large and/or the system consists of dozens of atoms, which is the case of the interaction between a nanocluster and a surface. On the other hand, IP require low computational cost while providing a good approximation to the structure and energetics of a material. I am interested in creating IP using DFT structures and energies; these potentials are used to predict low energy structures of nanoclusters on surfaces.  It is of my interest to use these techniques (especially in the Cu/ZnO system) to select good candidates, which can be refined with a more expensive approach.

Cu clusters on non-polar (1010) ZnO surface

Modelling Nanoparticles Catalysts on Metal Oxide Surfaces

Following the previous point, I am also very interested in finding energetically favourable structures of nanoparticles deposited on surfaces. Nanoparticle-surface systems are used widely in the catalytic industry; here, I am involved in the search for energetically favourable adsorption sites in an attempt to explain the catalytic activity of a particular system.

Formaldehyde production on MoO3/Fe2O3 surface