Phenol adsorption study on pristine, Ga-, and In-doped (4,4) armchair single-walled boron nitride nanotubes

Density functional theory (DFT) calculations at the B3LYP/6-31G* level were performed to investigate the adsorption of phenol on the pristine, Ga-, and In-doped (4,4) armchair single-walled boron nitride nanotubes (BNNTs). In comparison with the weak physical adsorption on the pristine BNNT, the hydroxyl group of phenol can lead to significant absorption on the BNNTs, thus suggesting a means for phenol storage. Binding energies corresponding to adsorption of phenol on the Ga and In sites in the model nanotubes was calculated to be −1.18 and −0.93 eV, respectively, and about 0.11 and 0.17 electron are transferred from phenol to the model nanotubes. In addition, the value for the fractional number of electrons transferred is negative, indicating that phenol acts as an electron donor. Frontier molecular orbital theory (FMO) and structural analyses show that the low energy level of the LUMO, high polar surface bonds, and large bond lengths of the Ga and In-doped (4,4) BNNT surfaces increase the adsorption of phenol on the model nanotubes.