Theoretical Study of SO Selective Detection from the Cr-Modified BN.

Sulfur dioxide is a toxic gas with serious environmental and health implications, making the development of selective and efficient sensors an urgent need. In this work, we investigate, using density functional theory (DFT)/B3LYP-D3/6-31G-(d,p) calculations, the potential of BN nanocages functionalized with Cr in different configurations (doped, decorated, and encapsulated) for application in SO chemical sensing. The results show that the encapsulated configuration (Cr@BN) exhibits the best combination of properties, including high electronic sensitivity (Δ = 79.3%), moderate adsorption energy ( = -0.96 eV), and an appropriate recovery time (τ = 167 s), key parameters for reusable sensors under atmospheric conditions. In addition, the system demonstrates high selectivity toward interfering gases such as CO, CO, COCl, CH, HS, N, and HO, corroborated by molecular dynamics simulations. The data analysis suggests that Cr functionalization represents a promising strategy for SO sensor design, although the system's performance remains dependent on the adsorption energy range and the experimental feasibility of metal encapsulation.