Identifying materials with intrinsic selectivity toward toxic gas molecules is essential for advancing the development of highly selective and sensitive gas sensors. In recent years, two-dimensional monolayers have emerged as particularly promising candidates for such applications. In the present study, we utilize density functional theory calculations to investigate the adsorption behavior of a newly synthesized two-dimensional polyaramid (2DPA) monolayer with respect to the hazardous gases SO₂ and H₂S. Our findings indicate that 2DPA exhibits adequate interactions, particularly with SO₂, positioning it as a highly effective material for pollutant capture. The calculated adsorption energies for SO₂ and H₂S on 2DPA are −1.11 and −0.82 eV, respectively, accompanied by charge transfers of approximately 12 and 2 milli-electrons. The adsorption of H₂S induces significant modifications in the electronic band gap of the monolayer, indicating a substantial electronic response and distinct molecule-specific sensing behavior. Furthermore, the 2DPA monolayer functions as a φ-type sensor for H₂S, demonstrating increased conductivity and decreased resistance upon exposure to the gas, as supported by current–voltage (I–V) analysis. Collectively, these results underscore pristine 2DPA as a highly efficient material for the adsorption and removal of SO₂, as well as a reusable, high-performance electronic and φ-type sensor for detecting H₂S.
