PNNL

Abstract

Implicit solvent models are a computationally efficient method of representing solid/liquid interfaces, which are prevalent in electrocatalysis, energy storage and materials science. However, electronic structure changes induced by the dielectric continuum at the metallic surface are not fully understood. To address this, we compare implicit and explicit water models for the Pt(111)/water interface using ab initio molecular dynamics (AIMD) simulations and Poisson-Boltzmann continuum solvation models within large scale density functional theory calculations. In our implicit solvation calculations, we show that the work function of the Pt(111)/water interface can be parametrized in terms of the electronic structure changes occurring at an equilibrated Pt(111)/water AIMD simulation (??pol = -1.27). We further compare the geometry and charge density based dielectric cavitation methods for the adsorption of phenol on Pt(111), and demonstrate how the ability to parametrize cavity of individual atoms is key to obtaining accurate enthalpy changes under aqueous conditions. In addition, we show that electronic structure changes induced by both solvent models follow largely similar trends in terms of density difference profiles and d-band projected density of states. We therefore demonstrate that it is possible to use an implicit solvent model to capture the main electronic effects of the solvent on the metallic surface and nanoparticles, which will allow computationally efficient simulations of interfacial processes.