The interplay between topological defects and CO2 and NH3 adsorption in graphene

Abstract

Topological defects in graphene, such as Stone–Wales rearrangements and non-hexagonal ring formations, significantly reshaped its electronic landscape and unlocked new adsorption pathways. Using density functional theory (DFT), this study revealed how these defects influenced the interaction with CO₂ and NH₃ molecules. The findings demonstrated that defect-induced distortions and localized electron density variations created active sites that enhanced molecular interactions. The interplay between defect geometry and molecular orientation governed adsorption strength, with defective graphene models containing 5-, 7- and 8-membered rings, showing enhanced adsorption energies compared to pristine graphene, particularly for NH₃ molecules. Particularly, the model with 5- and 8-membered ring defects (MG8) exhibited the strongest interactions for both CO₂ and NH₃. These results underscore the potential of tailoring graphene's defects for advanced gas storage, sensing, and catalysis applications, opening new avenues for designing more efficient graphene-based materials with tunable adsorption properties.