A Comparison of Modern Solvation Models for Oxygen Reduction at the Pt(111) Interface

Solvation effects play an important role in the thermodynamics of catalytic reactions, however, current implicit solvation models often fail to accurately capture specific local effects, such as hydrogen bonding, limiting their ability to systematically incorporate solvation effects into quantum mechanical simulations. In this study, we investigate the Reference Interaction Site Model (RISM) and apply it to the Platinum (111) interface, using the Oxygen Reduction Reaction as a case study. We compare RISM to the Charge-Asymmetric Nonlocally Determined Local-Electric (CANDLE) solvation model, which belongs to the class of Poisson-Boltzmann models. Our results demonstrate that RISM, with the appropriately parametrized water model, can accurately describe properties of the solvated Pt(111) surface such as solvation free energies, workfunctions, capacitances and capture subtle effects due to electrolyte concentration and explicit adsorbates. We find that including lone pairs in the water model proves to be crucial for obtaining accurate results, highlighting the importance of water non-bonding orbitals in solvation effects at the Pt(111) interface. Furthermore, RISM enables the computation of previously inaccessible properties, such as the solvent/electrolyte density near charged electrodes, providing valuable insights into the electrochemical double layer structure. Our findings suggest that RISM could serve as a computationally efficient alternative for studying electrode-electrolyte interfaces, paving the way for systematically incorporating solvation effects into computational studies.