Stability and reactivity at solid/liquid interfaces studied by ab initio calculations

Processes at solid-liquid interfaces are at the heart of many present day technological challenges related to the improvement of battery materials, electro-catalysis, fuel cells, corrosion and others. Obtaining the microscopic information needed to describe and quantify the underlying fundamental mechanisms is equally challenging to experiment and theory. Density functional theory (DFT) calculations are able to resolve processes at the microscopic scale. However, the modelling of electrochemical systems is particularly challenging. The main reason is the presence of different classes of materials and phenomena such as metal electrodes, liquid water, huge electric fields within the same system.
We discuss how by using DFT calculations for polar ZnO(0001) surfaces Pourbaix diagrams can be constructed. These diagrams provide direct insight into the role the aqueous electrolyte plays in shaping surfaces and the high selectivity of solvation effects [Phys. Rev. Lett. 120, 066101 (2018)]. Going beyond the thermodynamic description, we utilize our novel potentiostat design to study reactions at electrochemical solid/liquid interfaces under controlled bias [Phys. Rev. Lett. 120, 246801 (2018)]. Focusing on one of the most corrosive system under wet corrosion, the new approach is shown to solve a problem that puzzled corrosion scientists for more than 150-years: what is the underlying mechanism of the experimentally observed link between H-evolution under anodic conditions and Mg dissolution.