Boosting sensitivity of boron nitride nanotube (BNNT) to nitrogen dioxide by Fe encapsulation

Abstract The pristine boron nitride nanotube (BNNT) exhibits a poor chemical reactivity to some adsorbates, thus greatly limiting its application for the gas sensor. In the present work, using density functional theory (DFT) methods, we put forward a novel strategy to enhance the sensitivity of BNNT to nitrogen dioxide (NO 2 ) by the encapsulation of a single Fe atom inside its cavity. The results suggest that the NO 2 molecule can be only physically adsorbed on the pristine BNNT with a small adsorption energy (−0.10 eV). After the inclusion of the Fe atom inside BNNT (Fe@BNNT), the interaction of NO 2 molecules with this tube is significantly enhanced, leading to a transformation from the physisorption of on pristine BNNT to the current chemisorption. Interestingly, up to five NO 2 molecules can be adsorbed on this encapsulated BNNT along its circumference with the average adsorption energy of −0.52 eV, corresponding to a short recovery time (6 ms). Moreover, 0.38 electrons are transferred from the Fe@BNNT to the adsorbed NO 2 molecules, which is enough to induce the obvious change of its electrical conductance. Thus, we predict that the encapsulation of Fe atom inside BNNT would greatly boosts its sensitivity to NO 2 molecules, indicating its potential application as NO 2 sensors.