Methyl Red Adsorption on Pristine and Al and Ga-Doped (6, 0) and (7, 0) Zigzag BNNTs: A DFT Study

Adsorption of methyl red on pristine, Al, and Ga doped (6, 0) and (7, 0) zigzag boron nitride nanotubes was studied using the density functional theory method at the WB97XD/6-311G( d , p ) level of the theory. We considered different orientations of methyl red on these nanotubes. The adsorption energies, the highest and lowest molecular orbital energy levels, natural bond orbital analysis, dipole moments, and density of states have been calculated. The quantum theory of atoms in molecules was applied to the studied models. It was found that the adsorption energy of methyl red on pristine BNNT was small (about –9.7 kcal mol –1 ), implying a weak interaction and doping deforms the neighbor rings. But for the doped structure, better adsorption was observed. The calculated electron density, , and values in the studied models are the commonly accepted values for closed-shell interactions. The stabilization energy, E (2) values for the delocalization of the electrons between the bonds and Al atom are greater than Ga.