Explicit solvent effects on (1 1 0) ruthenium oxide surface wettability: Structural, electronic and mechanical properties of rutile RuO2 by means of spin-polarized DFT-MD

Abstract The structural, electronic and mechanical properties of crystalline ruthenium dioxide RuO2 in its rutile structure have been calculated via forefront spin-polarized Density Functional Theory (DFT) and DFT-Molecular Dynamics (DFT-MD) simulations. Notwithstanding RuO2 is known as a highly active catalyst for a wide number of (photo) electrochemical reactions in aqueous/humid environments, the study of the interaction of RuO2 surfaces with water has been confined largely to (static) surface science and water adsorption calculations. Herein, an atomistic understanding of bulk rutile RuO2 and explicit solvent effects on (1 1 0)-RuO2 facet are provided. We especially focus on the comprehension of the mechanistic interplay between surface wettability, interfacial water dynamics and surface chemical activity. Analysis and characterization of the interfacial water and H-bond environment reveal how explicit liquid water and its dynamics play a role in the surface reconstruction and in the hydrophobic nature of the (1 1 0)-RuO2 facet with a prevailing H-bond acceptor character. Moreover, we provide a dependence of physical and chemical properties, such as surface electric field and work function, from different degrees of surface wettability of the (1 1 0)-RuO2 facet. Results on bulk properties of crystalline ruthenium dioxide RuO2 are in good agreement with the nowadays available experimental evidences and previous DFT studies.