Adsorption of Transition Metal Cations (Cr2+, Mn2+, Fe2+, Cu+, Ag+ and Au+) on Boron Nitride Nanotube: Structural Analysis and Electronic Properties

This work uses the density functional theory (DFT) method to investigate the adsorption of transition metal cations (Cr2+, Mn2+, Fe2+, Cu+, Ag+, and Au+) on a single-walled boron nitride nanotube (SWBNNT). The systems with the highest adsorption energy within each ion group are the Fe2+@BNNT and Au+@BNNT, with observed values of -1474.30 and -242.15 kJ.mol-1, respectively. However, the Mn2+@BNNT and Ag+@BNNT structures exhibit the lowest values, measuring at -816.51 and -173.25 kJ.mol-1, respectively. The density of states computation is illustrated to validate the outcomes attained. The results from our analysis of electronic characteristics indicate that the percentage change in energy gap (%ΔE) is higher in the divalent complexes compared to the monovalent structures. The Fe2+@BNNT complex exhibits the smallest HOMO–LUMO energy gap, measuring 5.760 eV. This is followed by Cr2+@BNNT and Mn2+@BNNT, with energy gaps of 5.659 eV and 5.755 eV, respectively. However, the corresponding values for Au+@BNNT, Cu+@BNNT, and Ag+@BNNT are 6.046, 6.821, and 6.471 eV, respectively. Therefore, the divalent ions have the potential to be excellent candidates for enhanced adsorption capability.