Substantial improvement of electrocatalytic predictions by systematic assessment of solvent effects on adsorption energies

Electrocatalytic activities are largely determined by the interplay of adsorbates with substrates and solvents. Although capturing the interactions of those three components is usually arduous, here we provide a simple micro-solvation method to evaluate them in aqueous media. The method helps determine: (a) the number of water molecules making hydrogen bonds with the adsorbates, and (b) the energetic stabilization of the adsorbates by those hydrogen bonds. To evaluate the usefulness of the method, we consider CO2 reduction to CO, CH4, and CH3OH on Cu, Ag, Au, and Zn. Applying the calculated solvation corrections, we find good agreement with experiments in the predicted pathways and onset potentials, with an average error of only 0.07 V. Conversely, models with ad hoc or implicit solvation corrections predict unlikely pathways and onset potentials with considerably larger errors. These results indicate that accurate methods to assess solvent-adsorbate interactions contribute to improve computational electrocatalysis models.