Selective detection of sulfur trioxide in the presence of environmental gases by AlN nanotube

The adsorption of N2, O2, H2O, and SO3 gases was explored onto an AlN nanotube (AlNNT) by means of density functional theory computations. When N2 and O2, and H2O approached the AlNNT, the electronic characteristics of the AlNNT did not change dramatically. As SO3 approached the AlNNT, its adsorption released 21.8 kcal/mol of energy. As the electronic analysis demonstrated, there was an approximately −30.3% reduction in the HOMO–LUMO gap of the nano-tube (from 4.09 to 2.85 eV) after SO3 adsorption and there was a dramatic increase in electrical conductivity. Therefore, the AlNNT was capable of generating electrical noise as the SO3 molecules approached, showing that the AlNNT can be used as a promising sensor. It was found that this nanotube could selectively detect SO3 gas among the above-mentioned molecules. The recovery time (RT) for the AlNNT was 7.7 s for SO3 desorption, demonstrating a short RT.