(150c) Molecular-Level Insights into How Liquid Water Influences Thermodynamics at Water/Heterogeneous Catalyst Interfaces

Multiple societally important chemical reactions rely on catalytic processing in aqueous conditions, including biomass processing, electrochemical energy conversion, fertilizer production, and water purification. A goal of our work is to learn the molecular-level ways in which solvent molecules influence catalysis, both so that we can better understand catalyst fundamentals and so that we can garner insight needed to design new catalysts and optimize catalytic operating conditions. Experiments and simulations have uncovered a variety of ways in which water solvent influences catalytic phenomena. For example, it alters reaction intermediate and transition state energies, co-catalyzes certain reaction steps, and controls which catalytic pathways are followed. However, a comprehensive picture about how H₂O molecules influence catalytic behavior, including their influence on catalytic thermodynamics, remains unresolved. In this work, we use multiscale modeling involving density functional theory (DFT) and force-field molecular dynamics (ffMD) to examine how interfacial water influences the free energies of hydrophilic and hydrophilic species over hydrophobic Pt slabs, Pt electrodes, and supported Pt surfaces. We highlight how the polarity and polarizability of the solvent and the catalyst interface influence enthalpy and entropy of solvation and provide insight into how this influences catalytic phenomena.