Identifying materials that exhibit inherent selectivity for specific gas molecules can significantly facilitate the design of selective and sensitive gas sensors. Recently, researchers have identified two-dimensional (2D) monolayers as a highly promising category of materials for gas sensing applications. This article focuses on the investigation of the gas adsorption characteristics of a monolayer of penta-BCN toward SO₂, SOF₂, and SO₂F₂, key byproducts of SF₆ decomposition through density functional theory (DFT)-based first-principles computations. The results reveal that penta-BCN exhibits substantially strong adsorption energies, highlighting its potential for both gas detection and pollutant mitigation applications. Specifically, the adsorption energies of SO₂, SOF₂, and SO₂F₂ on the penta-BCN surface were calculated as 1.49, 2.37, and 2.90 eV, respectively. Corresponding charge transfers from the molecules to the monolayer were determined to be 180, 253, and 311 milli-electrons, respectively. Adsorption leads to notable changes in the electronic band gap of penta-BCN, reflecting a strong electronic response and demonstrating molecule-specific sensing characteristics. The monolayer functions as a φ-type sensor, showing enhanced conductivity and reduced resistance upon exposure to these toxic gases, as corroborated by current–voltage (I–V) analysis. Among the studied molecules, penta-BCN exhibits the highest sensitivity toward SO₂, SOF₂, and SO₂F₂, as evidenced by current sensitivity measurements. Overall, these findings underscore the promise of pristine penta-BCN as an efficient nanomaterial for the detection and capture of hazardous SF₆ decomposition products.
