Effects of Al Doping and Double-Antisite Defect on the Adsorption of HCN on a BC₂N Nanotube: Density Functional Theory Studies

By using density functional theory, we investigated the reactivity and electronic sensitivity of pristine and structurally manipulated BC2N nanotubes (BC2NNT) to a HCN molecule. It was mainly found that (i) the pristine BC2NNT can weakly adsorb the HCN with adsorption energy of −1.1 kcal/mol, and its electronic properties are not sensitive to HCN; (ii) doping the tube by an Al atom can largely improve its reactivity to HCN, but it does not have a significant effect on its sensitivity; (iii) B–B antisite defect on the tube wall can improve both reactivity and sensitivity of the tube to HCN; (iv) N–N antisite could improve neither the reactivity nor the sensitivity. Upon the adsorption of HCN on the B–B antisite defect, the HOMO–LUMO energy gap of the tube is significantly reduced from 2.23 to 1.82 eV and energy of 6.3 kcal/mol is released.