Methane combustion on Pd-based model catalysts: Structure sensitive or insensitive?

Area of Science:

• Surface Science
• Catalysis
• Computational Chemistry

Background:

• Palladium is a key catalyst in many chemical reactions.
• Understanding methane activation is crucial for catalysis.
• Surface structure significantly influences catalytic activity.

Purpose of the Study:

• To investigate the C-H bond breaking of methane on various palladium surfaces.
• To determine the effect of oxygen pre-coverage and palladium oxide formation on methane activation.
• To elucidate the structure sensitivity of this reaction.

Main Methods:

• Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA).
• Utilized repeated slab models for simulating palladium surfaces.
• Calculated adsorption energies and activation energy barriers.

Main Results:

• Methane C-H bond breaking is structure sensitive on clean and low-oxygen-coverage palladium surfaces.
• The reaction becomes structure insensitive on high-oxygen-coverage palladium and palladium oxide surfaces.
• Calculated adsorption energies and activation barriers provide mechanistic insights.

Conclusions:

• Oxygen coverage and surface structure play critical roles in methane activation on palladium.
• Palladium oxides exhibit different reactivity compared to metallic palladium.
• The findings support experimental observations regarding methane decomposition on palladium catalysts.