First-Principles Study on O₂ Adsorption and Dissociation Processes over Rh(100) and Rh(111) Surfaces

Area of Science:

• Surface Science
• Computational Chemistry
• Materials Science

Background:

• Understanding oxygen adsorption and dissociation on transition metal surfaces is crucial for catalysis.
• Rhodium (Rh) is a key catalyst, but detailed mechanisms of O2 interaction with its surfaces require further investigation.

Purpose of the Study:

• To systematically describe oxygen (O2) adsorption and dissociation on Rh(100) and Rh(111) surfaces.
• To identify preferred adsorption configurations, impinging trajectories, and dissociation pathways.
• To provide a foundation for large-scale kinetic modeling of rhodium-based catalysts.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to model O2 interactions with Rh surfaces.
• Analysis of adsorption states, transition pathways, and potential energy surfaces was performed.

Main Results:

• Parallel orientation dominates molecularly adsorbed O2 states and impinging processes on both Rh(100) and Rh(111).
• O2 dissociation occurs via precursor-mediated or direct pathways.
• Dissociation is facile on Rh(100) but involves a two-step rotation-dissociation process on Rh(111), influenced by coadsorbed species.

Conclusions:

• The study elucidates specific adsorption configurations and dissociation mechanisms for O2 on Rh surfaces.
• Findings highlight differences in O2 dissociation dynamics between Rh(100) and Rh(111).
• The detailed mechanistic insights can inform the development of more efficient catalytic processes.