Y-Shaped FeN₃ Active Sites on Graphyne for Catalytic CO Oxidation: A First-Principles Study

Area of Science:

• Computational Chemistry
• Materials Science
• Catalysis

Background:

• Catalytic oxidation of carbon monoxide (CO) is crucial for environmental remediation and industrial processes.
• Developing efficient and cost-effective catalysts is essential, with a focus on alternatives to noble metals.
• Graphyne, a novel 2D carbon allotrope, offers unique electronic properties for catalytic applications.

Purpose of the Study:

• To systematically investigate the CO catalytic oxidation process on Fe-N3 co-doped graphyne surfaces.
• To elucidate the reaction mechanisms, active sites, and kinetic behaviors of this catalytic system.
• To evaluate the potential of Fe-N3 graphyne as a single-atom catalyst for CO oxidation.

Main Methods:

• First-principles calculations were employed to model the catalytic system.
• The climbing-image nudged elastic band (CI-NEB) method was used to determine reaction pathways and energy barriers.
• Chemisorption energies and adsorption configurations of CO and O2 on FeN3 active sites were analyzed.

Main Results:

• Stable Y-shaped FeN3 active sites were successfully constructed on the graphyne surface.
• CO and O2 molecules chemisorbed strongly onto the FeN3 sites, with the C1 configuration showing higher adsorption capacity.
• The Eley-Rideal (ER1) pathway was identified as the preferred mechanism for CO oxidation, with low energy barriers for the rate-determining step (RDS) and efficient CO2 desorption and catalyst regeneration.

Conclusions:

• Fe-N3 co-doped graphyne exhibits excellent catalytic activity for CO oxidation, comparable to or better than noble-metal catalysts.
• The proposed Fe-N3 coordination doping provides a new strategy for designing high-performance graphyne-based single-atom catalysts.
• The study highlights the potential of modified graphyne materials for efficient catalytic applications.