Atomistic Simulation of Oxide and Mineral Surfaces and Interfaces

Atomistic simulation techniques represent a powerful complementary tool for studying oxide and mineral interfaces. The aim of the first part of this presentation is to describe some of the recent work on modelling these interfaces and in particular to review the attempts at studying the interaction of mineral surfaces with both solids and liquids.

The preferred approach is to model the interfaces using both atom-based potential models and DFT simulations, each one with its strengths and weaknesses. One of the problems with using DFT is the cost of the computer time which for any but the simplest interfaces is still prohibitive. However it is useful in giving atomistic insights and testing potential models. Once the models can be applied with confidence, energy minimisation or molecular dynamics can either be employed. The latter becomes essential when modelling the interfaces of oxides with liquids.

After giving a very brief description of the techniques I will illustrate how they are used by giving some examples of current projects. These include ongoing work on energy materials, pollutant separation and remediation and biomaterials; in each case the focus is to improve the understanding of the material’s behaviour, particularly the impact of additives and interfaces. The energy materials range from solid oxide fuel cell materials such as doped-ceria, to thermoelectrics and nuclear fuels. The work on pollutant separation and remediation includes identifying the factors controlling the transport and reactivity at surfaces, often in aqueous conditions of organics and carbon dioxide. Concerning materials for biomedicine, particular attention is given to cerium dioxide (CeO2) which is already established for use in catalysis, fuel cells, glass polishing and semiconductor manufacturing. Recently, CeO2 has been applied to the biomedical field due to its antioxidant activity, as well as protecting cells against radiation damage, inflammation and oxidative stress. Here, I present the latest research on the interaction of reactive oxygen species and on the influence of water on the redox properties of CeO2 surfaces and nanoparticles.

Thus the aim is to show that these modelling techniques are useful for giving insights into structural and dynamic properties of a wide range of complex interfaces.