Rigid- and polarizable-ion potentials for modeling Ru-polyoxometalate catalysts for water oxidation.

This work assesses the predictive power and capabilities of classical interatomic potentials for describing the atomistic structure of a fully inorganic water-oxidation catalyst in the gas phase and in solution. We address a Ru-polyoxometalate molecule (Ru-POM) that is presently one of the most promising catalysts for water oxidation due to its efficiency and stability under reaction conditions. The Ru-POM molecule is modeled with two interatomic potentials, the rigid ion model and the shell model potentials, which are used to perform molecular dynamics simulations. The predictions of these two approaches are discussed and compared to the available ab-initio data. These results allow us to establish the suitable level of theory to model complex heterogeneous interfaces between the Ru-POM and electrodes in solution.