NH3 on a BC3 nanotube: effect of doping and decoration of aluminum.

The adsorption of the NH3 molecule was investigated on pristine, Al-doped and Al-decorated BC3 nanotubes (BC3NT) using density functional theory calculations. It was found that NH3 prefers to be adsorbed on a B atom of the tube wall, releasing energy of 1.02 eV. Al-doping increases the acidity of the tube surface and, therefore, its reactivity toward NH3 so that the released energy in this case is about 1.62 eV, while decorating the BC3NT with Al atom decreases the acidity and reactivity. Although Al-doping has no significant effect on the electronic properties of the BC3NT, Al-decoration significantly reduces its HOMO/LUMO energy gap from 2.37 to 1.16 eV so that the tube becomes an n-type semiconductor. However, we believe that the acidity of the BC3NTs may be controlled by doping or decoration of Al atoms.