ABSTRACT Graphene oxide (GO) is a promising carbon‐based adsorbent due to its active oxygen functional groups and tunable electronic properties. This study employs density functional theory (DFT) at the B3LYP/6‐31G* level to investigate the adsorption of H 2 S, NO 2 , and SO 2 on four functionalized GO models: surface hydroxyl‐functionalized GO (SOH‐GO), surface epoxy‐functionalized GO (SO‐GO), edge hydroxyl‐functionalized GO (EOH‐GO), and edge epoxy‐functionalized GO (EO‐GO). The strongest adsorption energies were obtained for SOH‐GO‐H 2 S (−2.68 kcal/mol), EOH‐GO‐NO 2 (−5.08 kcal/mol), and EO‐GO‐SO 2 (−4.87 kcal/mol). Frontier Molecular Orbital (FMO) analysis showed notable band‐gap reduction, with EO‐GO‐SO 2 decreasing to 1.08 eV, indicating enhanced charge transfer. Density of States (DOS) profiles revealed increased peak intensities, such as SOH‐GO‐H 2 S rising from 2, 1, and 5 eV −1 to 3, 2, and 6 eV −1 . Chemical hardness values were the highest for SOH‐GO‐H 2 S ( η = 1.04 eV) and EOH‐GO‐NO 2 ( η = 0.83 eV), while EO‐GO‐SO 2 exhibited maximum softness ( β = 5.71 eV). The UV–visible bathochromic shifts up to 651 nm validated the adsorption mechanism. These findings provide strong computational insight for designing selective GO‐based gas sensors.
Bibi et al. (Thu,) studied this question.