First-principles statistical mechanics approach to step decoration at surfaces

TL;DR

This paper employs a first-principles statistical mechanics approach to investigate how oxygen atoms decorate atomic steps on a Pd(100) surface under conditions relevant to catalysis, revealing characteristic zigzag arrangements.

Contribution

It introduces a first-principles lattice-gas Hamiltonian method to study adsorbate ordering at surface steps under realistic conditions, providing new insights into surface defect structures.

Findings

Step decoration by oxygen occurs at near atmospheric pressures and 900 K.

Oxygen forms a zigzag pattern at atomic steps on Pd(100).

The approach offers insights into surface structure during catalytic processes.

Abstract

Using a first-principles parameterized lattice-gas Hamiltonian we study the adsorbate ordering behavior at atomic steps of a Pd(100) surface exposed to an oxygen environment. We identify a wide range of gas-phase conditions comprising near atmospheric pressures and elevated temperatures around 900 K, in which the step is decorated by a characteristic O zigzag arrangement. For catalytic processes like the high-temperature combustion of methane that operate under these conditions our approach thus provides first insight into the structure and composition at a prominent defect on the working surface.