Density functional theory study of pyrrole adsorption on Mo(110)

Area of Science:

• Surface Science
• Computational Chemistry
• Materials Science

Background:

• Understanding molecule-surface interactions is crucial for catalysis and materials design.
• Molybdenum (Mo) surfaces are important in various catalytic applications.
• Pyrrole adsorption behavior on transition metals influences surface reactions.

Purpose of the Study:

• To identify stable adsorption configurations of pyrrole on the Mo(110) surface.
• To investigate the energetics and mechanisms of pyrrole adsorption and potential decomposition.
• To utilize density functional theory (DFT) for accurate theoretical predictions.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• Various adsorption modes (parallel, tilted, perpendicular) for pyrrole and pyrrolyl were simulated.
• Linear Synchronous Transit (LST)/Quadratic Synchronous Transit (QST) calculations assessed activation energies.

Main Results:

• Pyrrole preferentially adsorbs in a parallel mu3,eta(5) configuration with significant adsorption energy (-28.7 to -31.5 kcal mol(-1)).
• A tilted mu3,eta(4) adsorption mode, likely due to lateral interactions at higher coverages, was also identified.
• Mo(110) did not promote hydrogen abstraction, making pyrrolyl adsorption energetically possible but experimentally unlikely.

Conclusions:

• Pyrrole adsorption on Mo(110) is primarily parallel, with a tilted mode coexisting under specific conditions.
• Lateral interactions, not surface phase transformation, drive the tilted configuration.
• Pyrrole decomposition to pyrrolyl on Mo(110) is unlikely under typical experimental conditions.