Hydroxyl Functionalized Hydrogen‐Substituted Graphdiyne for Tracing and Trapping of Nitrogen and its Oxides: A First‐Principles Study

The essential role of transportation in daily life has led to increased automobile use and a significant rise in outdoor air pollution. Diesel‐powered vehicles, especially in urban areas, are major sources of nitrogen and its oxides (N2, N2O, NO, and NO2), which are linked to cardiovascular and respiratory diseases. To address these environmental challenges, Hydrogen‐substituted Graphdiyne (HsGDY), a next‐generation carbon‐based material, is modified through hydroxyl (─OH) functionalization to enhance gas adsorption properties. Density functional theory (DFT) calculations are employed to assess the structural stability and electronic properties of hydroxylated HsGDY (OH‐HsGDY) for nitrogen and its oxides adsorption. The electronic property analysis, including TDOS and PDOS, showed a reduction in energy gap (Eg) after adsorption, indicating enhanced electrical conductivity. PDOS analysis revealed orbital overlap, supporting strong adsorption. NCI‐RDG analysis confirmed the role of noncovalent interactions in gas capture. Charge density difference and Löwdin charge analysis indicated significant charge transfer during gas adsorption. Recovery time analysis showed rapid desorption, highlighting excellent reusability. Overall, these findings establish OH‐HsGDY as a promising material for the selective detection and efficient capture of nitrogen and its oxides.