Phosphoborane nanotube as a sensing material towards benzaldehyde and benzoic acid - a DFT study

Exposure to benzaldehyde and benzoic acid poses risks to the environment and human health. The phosphoborane nanotube (PB-NT) has been identified as the primary material for research to detect these toxic and volatile substances. Besides, PB-NT material exhibits geometric stability, underpinned by a negative formation energy. After the adsorption of the benzaldehyde and benzoic acid onto the PB-NT, a reduction in the energy gap at all sites are noticed. Moreover, Density Functional Theory (DFT) calculations substantiate the geometric stability of PB-NT, which exhibits a band gap of 1.282 eV. Upon the adsorption, the band gap reduces significantly, decreasing by up to 60.76% for benzaldehyde and 34.63% for benzoic acid, thereby enhancing conductivity. The computed adsorption energy values, - 0.926 eV for benzaldehyde and - 1.196 eV for benzoic acid indicate that these interactions are characterized as physisorption. This property facilitates rapid desorption and contributes to the reusability of the sensor. Notably, the estimated recovery time for benzaldehyde is in the millisecond range, positioning PB-NT as a promising candidate for real-time monitoring applications. Furthermore, ab initio molecular dynamics (AIMD) simulations conducted at 300 K confirm the thermal stability of PB-NT. The future outcome of the proposed work with these results will lay inroads to the practical applicability of PB-NT in air quality sensors and biosensors warranting assessment for commercial viability, and enhancing its feasibility for practical use in various industries.