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

摘要

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