Electrochemical sensing and detection of phosgene and thiophosgene chemical warfare agents (CWAs) by all-boron B38 fullerene analogue: a DFT insight

Abstract

Chemical warfare agents (CWAs) are very toxic and dangerous to all forms of life. With the purpose of protecting environment and human health, it is essential to identify and eliminate these threats quickly and effectively. B38 nanocage as a sensor is rarely discussed therefore the detection of harmful CWAs (phosgene and thiophosgene) by using the B38 nanocage has been examined using density functional theory (DFT) parameters. Optimized geometries, adsorption energies, NCI, NBO, FMO and QTAIM studies have been used to analyze the interactions between CWAs and the B38 nanocage. The adsorption energy values indicate that CWAs are adsorbed on the B38 nanocage in a stable manner and the reaction is exothermic. The complex T-S@B38-B have the greatest conductivity, lowest stability and maximum sensitivity due to its narrow energy gap of 1.9648 eV while complex T-S@B38-6r, with the highest energy gap of 1.9988 eV is the most stable. The global reactivity parameters indicate that the complex T-S@B38-B has the highest electrophilicity index, the lowest chemical hardness and the highest chemical softness and resultantly leads to highest sensitivity. Van der Waals forces are present between the B38 nanocage and CWAs as shown by NCI and QTAIM studies. The formation of new energy level in PDOS of B38 results into the interaction of CWAs with the surface of B38. Nanocage sensing capacity is evaluated by measuring E g value, sensitivity and recovery time of the complex. B38 has the highest sensitivity and shortest recovery time for T-S@B38-B and P-Cl@B38-B complex with 5.90 × 10−3 and 2.78259 × 10−12 s values which results the B38 nanocage is more effective sensor for detecting CWAs. Consequently, B38 nanocage is recommended as fine future sensor for the sensing of phosgene and thiophosgene.