Stable reconstruction of the (110) surface and its role in pseudocapacitance of rutile-like RuO2

TL;DR

This study uses computational methods to identify stable surface reconstructions of rutile-like RuO2, revealing new structures that explain its pseudocapacitive behavior and match experimental observations.

Contribution

The paper introduces two new stable surface reconstructions of RuO2 (110) and demonstrates their relevance to pseudocapacitance and stability under various conditions.

Findings

Identified RuO4-(2x1) and RuO2-(1x1) reconstructions as stable surfaces.

RuO4-(2x1) matches experimental STM images and is thermodynamically stable.

The new reconstruction explains the pseudocapacitance of RuO2 cathodes.

Abstract

Surfaces of rutile-like RuO2, especially the most stable (110) surface, are important for catalysis, sensing and charge storage applications. Structure, chemical composition, and properties of the surface depend on external conditions. Using the evolutionary prediction method USPEX, we found stable reconstructions of the (11) surface. Two stable reconstructions, RuO4-(2x1) and RuO2-(1x1), were found, and the surface phase diagram was determined. The new RuO4-(2x1) reconstruction is stable in a wide range of environmental conditions, its simulated STM image perfectly matches experimental data, it is more thermodynamically stable than previously proposed reconstructions, and explains well pseudocapacitance of RuO2 cathodes.