A first-principles study of the adsorption behavior of CO on Al- and Ga-doped single-walled BN nanotubes

► The adsorption energy of CO molecule on surfaces of Al- and Ga-doped (6, 0), (8, 0), and (5, 5) BNNTs are studied. ► Binding energy of CO on outer walls of Al- and Ga-doped (6, 0) and (8, 0) BNNT are energetically more notable in comparison with Al- and Ga-doped (5, 5) BNNT. ► Our computations indicate that the Al- and Ga-doped BNNT can be used as potential sensor for CO molecule. ► The energy gap of BNNT is decreased in all of the cases for CO adsorption.