The PhD project was aimed to understand the role of the solvent in the hydrogen oxidation and evolution reactions on platinum and gold. This approach sheds light on the molecular origins... Show more The PhD project was aimed to understand the role of the solvent in the hydrogen oxidation and evolution reactions on platinum and gold. This approach sheds light on the molecular origins affecting the kinetics of the hydrogen evolution reaction, as a promising source of energy in the era of sustainable energy production and storage. Ultimately, this work demonstrates the importance of the solvent in the hydrogen electrocatalysis, specifically, water, by settling its role as a solvent, as a proton donor, and by preferential proton solvation, clarifying a long-existing debate regarding the pH dependence of the hydrogen evolution, and setting a path for future exploration of solvent-electrode interfaces for the tailoring of electrocatalytic reactions. Show less
In this study we focused on the simulation of the interaction of water and its dissociation products hydrogen, oxygen and OH with platinum surfaces that contain a periodic arrangement of single... Show moreIn this study we focused on the simulation of the interaction of water and its dissociation products hydrogen, oxygen and OH with platinum surfaces that contain a periodic arrangement of single-atom-high steps. We simulate these interactions using the framework of density functional theory and employ high-performance computing resources such as the Cartesius supercomputer of SURFsara. We find that the two possible types of step edges exhibit increased binding strengths compared to the flat parts of the interface. This binding strength is a key factor in the chemical reactivity of these surfaces. Furthermore, we investigate the structure of higher coverages of water molecules around the step edges, where we observe surprising changes, namely the appearance of four, five and seven-membered rings, compared to the six-membered rings that are usually observed on the flat surfaces. Our predictions for these structures are confirmed using high-resolution scanning tunneling microscopy data. Our results are among the first simulations of high-coverage water adsorption on regularly stepped platinum surfaces, which will help advance our understanding of solvation effects at the step edges, which are relevant for the fields of solvation science, electrochemistry and surface science. Show less
