A computational study of adsorption H2S gas on the surface of the pristine, Al&P-doped armchair and zigzag BNNTs

Density function theory is used to study the H2S adsorption on the surface of pristine, Al-, P- and Al&P- doped (4, 4) armchair and (8, 0) zigzag BNNTs. All considered different models for H2S adsorption on the exterior and interior surface of nanotube are optimized by using B3LYP/6-31G (d, P) level of theory. The adsorption energy values (E-ads) of the B-I, B-II,C-I, D-I, D-II, F-I, F-II and H-II models are negative, while the E-ads values for the A-III, B-III, C-III, D-III, E-III, F-III, G-III and H-III models are positive. On the other hand, Al, P and Al&P doped in all models increase significantly the adsorption energy of H2S on the surface of BNNTs, and so the selectivity of nanotube for adsorbing and making a sensor of H2S increase significantly from original state. The positive values of the charge transfer parameters (Delta N) and more values of the electronic chemical potentials of H2S gas for all studied models demonstrate that H2S gas in this system has a donor electron effect on the nanotube. The MEP results display that a low charge transfer occurs from H2S gas toward nanotube, resulting in a weak ionic bonding in the BNNTs' surface.