The surface chemistry of metal-oxygen interactions: a first-principles study of O:Rh(110)

TL;DR

This study uses first-principles density functional theory to analyze the surface chemistry and oxygen interactions on Rh(110), revealing how oxygen coverage affects surface structure, energy, and bonding characteristics.

Contribution

It provides detailed computational insights into oxygen adsorption, reconstruction, and bonding on Rh(110), including coverage-dependent structural and energetic changes.

Findings

Oxygen induces surface reconstruction at half monolayer coverage.

Maximum chemisorption energy occurs on unreconstructed surface at one monolayer coverage.

Strong bonds form with low-coordinated metal atoms, influencing adsorbate interactions.

Abstract

We report on a computational study of the clean and oxygen-covered Rh(110) surface, based on density-functional theory within the local-density approximation. We have used plane-wave basis sets and Vanderbilt ultra-soft pseudopotentials. For the clean surface, we present results for the equilibrium structure, surface energy, and surface stress of the unreconstructed and $(1\times 2)$ reconstructed structures. For the oxygen-covered surface we have performed a geometry optimization at $1\over 2$, 1, and 2 monolayer oxygen coverages, and we present results for the equilibrium configurations, workfunctions and oxygen chemisorption energies. At half monolayer coverage, we find that oxygen induces a $(1\times 2)$ reconstruction of the surface, while at one monolayer coverage the chemisorption energy is highest for the unreconstructed surface. Our results are rationalized by a simple tight-binding description of the interaction between the O$-2p$ orbitals and the metal valence states. The resulting bonds are stronger when established with low coordinated metal atoms, and give rise to an effective adsorbate-adsorbate interaction when two oxygen atoms are bound to the same metal orbital.