S.O.S: Shape, orientation, and size tune solvation in electrocatalysis

Area of Science:

• Electrochemistry
• Computational Chemistry
• Surface Science

Background:

• Electrochemical reactivity models, like volcano plots, rely on adsorption free energies.
• Solvation free energies critically influence adsorption and interfacial transport, especially for small hydrophobic molecules.
• Current models often overlook detailed solvation effects at metal/aqueous interfaces.

Purpose of the Study:

• To investigate the role of solvation free energies in electrochemical reactions at metal/aqueous interfaces.
• To quantify the impact of solute size, shape, and orientation on adsorption free energy.
• To develop an improved theoretical model accounting for these solvation effects.

Main Methods:

• Constant potential molecular dynamics simulations were employed.
• Analysis focused on solvation contributions to adsorption free energy.
• A new theoretical model, the S.O.S. model, was developed.

Main Results:

• Solute shape and orientation have significant, previously underestimated, effects on adsorption free energy.
• Solvation effects modulate both adsorption free energy and interfacial transport.
• The S.O.S. model successfully incorporates size, orientation, and shape effects.

Conclusions:

• Accurate modeling of metal/aqueous interfaces requires explicit consideration of solute shape and orientation.
• The S.O.S. model provides a more comprehensive understanding of solvation effects in electrochemistry.
• This work advances the fundamental understanding of reactivity at electrified interfaces.