Pyridine adsorption and diffusion on Pt(111) investigated with density functional theory

Area of Science:

• Surface Science
• Computational Chemistry
• Materials Science

Background:

• Pyridine adsorption on metal surfaces is crucial for catalysis.
• Understanding pyridine's behavior on platinum is key for developing new catalytic processes.
• Previous experimental studies provide limited mechanistic insights.

Purpose of the Study:

• To investigate the adsorption, diffusion, and dissociation mechanisms of pyridine on Pt(111) using theoretical calculations.
• To elucidate the preferred adsorption geometry and diffusion pathways.
• To determine the energy barriers for pyridine dehydrogenation on Pt(111).

Main Methods:

• Van der Waals-corrected density functional theory (DFT) calculations.
• Extensive search for local minima on the adsorption potential energy surface.
• Analysis of diffusion pathways and reaction barriers.

Main Results:

• Pyridine adsorbs parallel to the Pt(111) surface.
• The most favorable diffusion pathway involves small rotational steps with a barrier of 0.53 eV.
• Dehydrogenation of pyridine to α-pyridyl has an energy barrier of 0.71 eV and enthalpy of 0.18 eV.

Conclusions:

• The theoretical findings rationalize existing experimental observations for pyridine on Pt(111).
• The C2-Pt π-bond strength influences the pyridine diffusion pathway.
• This work provides a detailed atomistic understanding of pyridine-surface interactions.