Ab initio theory of Cr$_2$O$_3$ surface chemistry in solution

TL;DR

This paper introduces a new density functional theory approach to study how water as a solvent affects the surface chemistry of Cr₂O₃, revealing significant effects on hydrogen binding but not chloride adsorption.

Contribution

It presents the first ab initio study of Cr₂O₃ surface chemistry in solution using a novel dielectric environment-aware density functional theory.

Findings

Water has little impact on chloride ion adsorption compared to vacuum.

Water dramatically affects hydrogen binding on the Cr₂O₃ surface.

Dielectric screening by water influences passivation properties.

Abstract

Using a new form of density functional theory for the {\em ab initio} description of electronic systems in contact with a dielectric environment, we present the first detailed study of the impact of a solvent on the surface chemistry of Cr$_2$O$_3$, the passivating layer of stainless steel alloys. Compared to vacuum, we predict that the presence of water has little impact on the adsorption of chloride ions to the oxygen-terminated surface but a dramatic effect on the binding of hydrogen to that surface. These results indicate that the dielectric screening properties of water are important to the passivating effects of the oxygen-terminated surface.