Effect of Oxygen-containing Functional Groups on the NO₂ Adsorption and Reduction by Activated Carbon: A Density...

Area of Science:

• Materials Science
• Environmental Chemistry
• Computational Chemistry

Background:

• Activated carbon effectively removes nitrogen dioxide (NO2) from air.
• Surface oxygen-containing functional groups (OFGs) significantly influence NO2 adsorption-reduction performance.
• The precise mechanisms of OFGs in NO2 reactions are not fully understood.

Purpose of the Study:

• To investigate the microscopic reaction pathways of NO2 on carbon edge structures with different OFGs.
• To elucidate the role of OFGs in NO2 adsorption, dissociation, and NO desorption.
• To identify optimal carbon structures and conditions for enhanced NO2 removal.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Wave function analysis.
• Thermodynamic and kinetic analyses.
• Modeling of carbon edge structures with six different OFGs.

Main Results:

• Most OFGs inhibit NO2 adsorption and N-O bond cleavage through van der Waals interactions.
• OFGs have a negligible effect on NO desorption due to localized interactions.
• Zigzag edge structures demonstrate superior reactivity for NO2 reduction.
• Carbon materials synthesized below 400 °C with minimal OFGs are more favorable for NO2 conversion.

Conclusions:

• Understanding OFG mechanisms provides a molecular-level basis for designing better carbon adsorbents.
• Optimizing carbon structure (zigzag edges) and minimizing OFGs enhances NO2 removal efficiency.
• This research offers practical guidance for developing advanced materials for air purification.