First‐Principles Investigation of Na‐Decorated ─OH Functionalized Hydrogen‐Substituted Graphdiyne for Tracing and Trapping of Nitrogen and its Oxides

ABSTRACT

Air pollution has become a major environment concern, with vehicular emissions identified as a primary contributor. Particularly, diesel‐powered vehicles are noted for their emissions of nitrogen and its oxides (N ₂ , N ₂ O, NO, and NO ₂ ), resulting in cardiovascular and respiratory diseases. To capture these gases, 2D carbon‐based materials have been extensively explored for gas‐sensing applications. In this study, hydroxyl (─OH) functionalized hydrogen‐substituted graphdiyne (OH‐HsGDY), is modified via Na atom decoration to enhance its adsorption properties. Density functional theory (DFT) calculations have been employed to investigate Na adsorption sties, electronic properties of Na decorated OH‐HsGDY (Na‐OH‐HsGDY) and its adsorption efficiency toward nitrogen and its oxides. Among the gases studied, NO ₂ exhibits the most negative adsorption energy (−3.324 eV), while electronic property analysis (TDOS/PDOS) reveals a reduced energy gap and significant orbital overlap upon adsorption. The non‐covalent interaction (NCI) scatter plots and reduced density gradient (RDG) analyses further confirm the nature of the interactions. In addition, charge density difference and Bader charge analyses indicate notable charge transfer (0.8257 e ^─ ) for the NO ₂ system. Additionally, enhanced electrical conductivity leads to a high sensitivity of −95% toward NO ₂ . These results have positioned Na‐OH‐HsGDY as potential nitrogen and oxides sensing material.