Potential energy surfaces for oxygen adsorption, dissociation, and diffusion at the Pt(321) surface

Area of Science:

• Surface Science
• Computational Chemistry
• Materials Science

Background:

• Understanding oxygen behavior on metal surfaces is crucial for catalysis.
• Kinked surfaces exhibit unique reactivity compared to flat surfaces.
• Platinum is a key catalyst in many industrial processes.

Purpose of the Study:

• To investigate oxygen adsorption, diffusion, and dissociation on the Pt(321) kinked surface.
• To determine binding energies and site preferences for atomic and molecular oxygen.
• To elucidate the mechanisms and kinetics of oxygen diffusion and O(2) dissociation.

Main Methods:

• First-principles, periodic supercell calculations.
• Density Functional Theory (DFT) based simulations.
• Analysis of binding energies, diffusion barriers, and reaction pathways.

Main Results:

• Atomic and molecular oxygen preferentially bind to bridge sites involving coordinatively unsaturated kink Pt atoms.
• Binding energies correlate with Pt coordination numbers, with chirality-induced site differences.
• Oxygen diffusion is rapid between sites around the kink but anisotropic and slower long-range compared to Pt(111).
• Four O(2) dissociation pathways were identified, consistent with facile experimental observations.

Conclusions:

• The Pt(321) surface offers distinct binding and diffusion characteristics for oxygen compared to Pt(111).
• Kink site geometry significantly influences oxygen adsorption, diffusion anisotropy, and dissociation.
• Computational findings provide insights into oxygen surface chemistry relevant to platinum catalysis.