First-principles study of O2 and Cl2 molecule adsorption on pristine doped boron nitride nanotubes

The adsorption of oxygen (O-2) and chlorine (Cl-2) on pristine and impurity X atom (X = C, Al, Si, Ca, Mn, Fe, Co, Ni, Cu or Ge) doped (10,0) and (6,6) boron nitride nanotubes (BNNTs) has been theoretically studied using first-principles approach based on density functional theory. Comparing with the formation energy, the distance between gas molecule and X atoms, the Bader charge transfer, and the elevation of the dopant atom, we find that the O-2 or Cl-2 molecule undergoes weakly physical adsorption on the pristine (10,0) and (6,6) BNNTs, and the Al, Si, and Mn atoms are suitable dopants to modify BNNTs to enhance the reactivity of the tube to gas molecules. This work reveals that the sensitivity of BNNT-based chemical gas sensors for O-2 and Cl-2 can be drastically improved by introducing appropriate dopant, and Al-, Si-, and Mn-doped BNNTs can be used as O-2 and Cl-2 gas sensor manufacturing raw materials.