Adsorption of nitrogen oxides on modified BN nanosheets: improved gas sensing and functionalization

Abstract

The sensing mechanism of modified hexagonal boron nitride toward nitrogen oxide molecules (NO, NO₂ and N₂O) was systematically investigated by using density functional theory calculations. The results indicate that the defects and doping induce a significant redistribution of the electron density in the BN sheets, leading to an improvement in the adsorption energy of the nitrogen oxide molecules. For NO molecules, the adsorption effect on Rh-doped B vacancy and Rh-doped N vacancy systems is superior to that of B vacancies and N vacancies. N vacancies have excellent adsorption of both NO₂ and N₂O molecules, while N₂O is of low physical adsorption in other systems. Furthermore, the effect of an applied external electric field on molecular adsorption has also been studied. The application of an external electric field could prevent strong interactions between the nitrogen oxides on modified BN nanosheets. In summary, B vacancy, N vacancy, Rh-doped B vacancy and Rh-doped N vacancy BN sheets can be regarded as promising and highly sensitive molecular sensing materials for NO, NO₂, and N₂O.