CO-Induced Restructuring on Stepped Pt Surfaces: A Molecular Dynamics Study

TL;DR

This study uses molecular dynamics simulations to investigate how CO molecules induce restructuring on stepped platinum surfaces, revealing the influence of surface features and CO interactions on surface reconstruction.

Contribution

It introduces a classical interaction model based on experimental and DFT data to analyze CO-induced surface restructuring on various platinum vicinal surfaces.

Findings

CO facilitates step edge straightening on Pt(321).

Step edge wandering and reconstruction depend on edge atom binding strength.

Plateau width influences the likelihood of step doubling events.

Abstract

The effects of plateau width and step edge kinking on carbon monoxide (CO)-induced restructuring of platinum surfaces were explored using molecular dynamics (MD) simulations. Platinum crystals displaying four different vicinal surfaces [(321), (765), (112), and (557)] were constructed and exposed to partial coverages of carbon monoxide. Platinum-CO interactions were fit to recent experimental data and density functional theory (DFT) calculations, providing a classical interaction model that captures the atop binding preference on Pt. The differences in Pt-Pt binding strength between edge atoms on the various facets were found to play a significant role in step edge wandering and reconstruction events. Because the mechanism for step doubling relies on a stochastic meeting of two wandering edges, the widths of the plateaus on the original surfaces was also found to play a role in these reconstructions. On the Pt(321) surfaces, the CO adsorbate was found to assist in reordering the kinked step edges into straight {100} edge segments.