A computational study on interactions of Ni- and Pt-doped boron nitride nano tubes with NH_3 in presence and absence of electric fields

摘要

The density functional theory (DFT) has been used to study the surface interactions of pristine, Ni- and Pt-doped (4,4), (5,5), (7,7) and (8,8) boron nitride nanotubes (BNNTs) with ammonia (NH_3) molecules. To verify the impact of external electric field (EF) on the surface interactions between the nanotubes and adsorbed NH_3 molecules, in this work, the NH_3/(4,4) BNNTs adsorbed complex system under an applied EF with strength of 3×10~(-2) a.u. and 4×10~(-2) a.u., along the z axis (perpendicular to the tube axis) has been investigated. It was shown that after doping of Ni and Pt atoms, the primary symmetry of BNNTs was decreased, enhancing the chemical activity of BNNTs towards NH_3 molecules and subsequent resulting in dramatic changes of their electronic properties. Our overall results indicated that, in addition to the Ni and Pt doping, the applied external EF could enhance the sensitivity of BNNTs toward NH_3 molecule, which can be considered as a new strategy of sensor fabrication.