Direct versus hydrogen-assisted CO dissociation on the Fe (100) surface: a DFT study

Area of Science:

• Surface Science
• Chemical Kinetics
• Materials Science

Background:

• Carbon monoxide (CO) dissociation is crucial in many catalytic processes.
• Understanding CO dissociation on metal surfaces informs catalyst design.
• Iron (Fe) is a common catalyst material.

Purpose of the Study:

• To elucidate the primary mechanisms of CO dissociation on the Fe(100) surface.
• To investigate the role of hydrogen in modifying CO dissociation pathways.
• To compare the relative importance of different reaction channels.

Main Methods:

• Theoretical calculations (e.g., Density Functional Theory) were likely employed.
• Analysis of reaction intermediates and transition states.
• Kinetic modeling under varying surface coverages and pressures.

Main Results:

• Identified three principal CO dissociation pathways on Fe(100): direct CO→C+O, and two H-assisted routes (via HCO and COH intermediates).
• High hydrogen pressure and surface coverage promote the H-assisted pathway involving HCO formation (H+CO↔HCO→CH+O).
• This HCO pathway can compete effectively with direct CO dissociation under specific conditions.

Conclusions:

• The Fe(100) surface exhibits complex CO dissociation behavior influenced by hydrogen.
• Hydrogen co-adsorption significantly alters the energetic landscape and product distribution.
• Control of hydrogen pressure and surface coverage is key to directing CO dissociation pathways in catalysis.