Tailoring gas sensing properties of armchair graphene nanoribbons via transition metal doping: a first-principles investigation on NO, NO₂, and NH₃ molecules

Abstract This study explores the gas sensing capabilities of armchair graphene nanoribbons (AGNR) for nitrogen-based gases (NO, NO 2 , and NH 3 ) using DFT calculations. The results show that pristine AGNR has limited sensitivity to these gases. However, doping AGNR with transition metals (Ti, V, Cr, Mn, and Fe) significantly improves its adsorption performance. The adsorption behavior is analyzed through geometrical changes, binding energies, binding distances, density of states, and band structure. Notably, Mn-AGNR showed up to 20 times greater sensitivity to NO gas. For NO 2 , Mn-AGNR and V-AGNR demonstrated increased adsorption energies of −3.39 eV and −3.99 eV, respectively. Additionally, Fe-AGNR proved highly effective for NH 3 gas adsorption. It highlights Mn-AGNR, V-AGNR, and Fe-AGNR as particularly effective for sensing NO, NO 2 , and NH 3 gases, respectively, and offers a comparative analysis to identify optimal doping strategies for enhanced gas sensing performance.