DFT studies on the interactions of pristine, Al and Ga-doped boron nitride nanosheets with CH3X (X=F, Cl and Br)

Abstract

The adsorption of CH3F, CH3Cl and CH3Br halomethanes on pristine boron nitride (BNNS), aluminum-doped boron nitride (BN(Al)NS) and Gallium-doped boron nitride (BN(Ga)NS) nanosheets were investigated by two-dimensional periodic boundary condition density functional theory methods. All nanosheets were geometrically optimized at B3LYP/6-311 + G (d) level, and single point energy calculation at M06-2X, ωB97X-D3 and CAM-B3LYP/6-311 + G(d) levels of theory were also performed. NBO and QTAIM analyses were also performed, and values of the Wiberg bond index (WBI), partial natural charges and donor-acceptor interactions were further analyzed. The obtained adsorption energy values (Eads) indicate that the tendency of nanosheets to adsorb CH3F and CH3Br to their surfaces are in the order of BN(Ga)NS > BN(Al)NS > BNNS. However, for CH3Cl, which adsorb with a significant lower Eads compared to the other halomethanes, this trend is as follows: BN(Al)NS > BN(Ga)NS > BNNS. Moreover, it was found that, the affinity of halomethanes to adsorb onto the surface of nanosheets is in the order of CH3Br > CH3F ≫ CH3Cl. Generally, it seems that BN(Al)NS and BN(Ga)NS are promising candidates in designing a new type of solid state halomethane gas sensors.