Ammonia monitoring by carbon nitride nanotubes: A density functional study

Abstract The adsorption of one to three NH 3 molecule(s) on the exterior surface of a carbon nitride nanotube (CNNT) has been investigated using density functional theory. It has been found that a NH 3 molecule is physically adsorbed on the tube surface with adsorption energies in the range of 15.47 to 25.08 kJ/mol. The most stable obtained configuration is that in which the NH 3 molecule has been adsorbed above center of a porous site of the tube surface via forming hydrogen bonds. The adsorption of the second and third NH 3 molecules at the porous sites is independent of each other. Density of states analysis reveals that the intrinsic semiconductor CNNT may transform to an extrinsic n-type semiconductor with higher electrical conductance upon the adsorption of NH 3 molecules. The obtained results suggest that the CNNTs may be potentially used in NH 3 sensor applications.