Structures, stabilities and electronic properties of carbon monoxide adsorbed and embedded boron nitride nanotubes with different lengths

The boron nitrides as excellent sensors are adopted to detect some harmful gases. The adsorption sites and lengths of the boron nitrides are very important to improve the adsorption capacity. The structures, stabilities and electronic properties of the COBmNm and CO@BmNm (m=48, 96 and 144) nanotubes with different lengths have been investigated by using density functional theory. The longer BmNm, COBmNm and CO@BmNm clusters are more stable. The adsorption of the CO molecules at the ends of BmNm nanotubes competes with the insertion of the CO molecules in the BmNm nanotubes. The COBmNm clusters exhibit higher chemical reactivity than the CO@BmNm clusters. The lengths of the BmNm nanotubes have little effect on the chemical reactivity of the nanotubes. The charge transfer amounts of the O atoms increase while those of the C atoms of the COBmNm and CO@BmNm clusters are almost the same with the increase of cluster lengths. The CO molecules lose fewer electrons (0.174|e|, 0.164|e|, 0.158|e|) to the BmNm nanotubes of the COBmNm clusters while the CO molecules obtain fewer electrons (-0.028|e|, -0.045|e|, -0.045|e|) from the BmNm nanotubes of the CO@BmNm clusters.