Interaction investigation of single and multiple carbon monoxide molecules with Fe-, Ru-, and Os-doped single-walled carbon nanotubes by DFT study: applications to gas adsorption and detection nanomaterials.

Due to the large surface area and unique electronic property, single-wall carbon nanotube (SWCNT) is being used for adsorption and detection nanomaterials, which can be used to reduce the CO pollution effect on the environment. In the present work, the adsorptions of single and multiple CO molecules on pristine and transition metal (TM = Fe-, Ru-, and Os)-doped SWCNT were investigated in terms of geometric, energetic, and electronic properties using density functional theory calculation. Calculated results display that the adsorption of CO molecule on the SWCNTs is energetically favorable. The TM-doped SWCNT are more highly interactive to CO adsorption than that of pristine SWCNT. An Os-doped SWCNT displays the strongest interaction with single and multiple CO molecules comparing with the Fe- and Ru-doped SWCNT. The TM doping on SWCNT can induce the charge transfer between CO molecule and the SWCNT. The energy gap and density of state are clearly changed when CO molecule interacts with TM-doped SWCNT, resulting in dramatic changes of their electronic properties. Therefore, TM-doped SWCNT are possibly used as potential CO storages/absorbents or sensor material for CO detection in the environment. Graphical abstract.

Density functional investigation of hydrogen gas adsorption on Fe-doped pristine and Stone-Wales defected single-walled carbon nanotubes.

The adsorptions of hydrogen molecule of the Fe - doped pristine and Stone - Wales defected armchair (5,5) single - walled carbon nanotubes (SWCNTs) compared with the pristine SWCNT were investigated by using the density functional theory at the B3LYP/LanL2DZ level. The doping of Fe atom into SWCNTs occurring via an exothermic process was found. The adsorptions of hydrogen molecule on the Fe - doped structures of either perfect or SW defected SWCNTs are stronger than on their corresponding undoped structures. The structural and electronic properties of the pristine and SW defected SWCNTs, their Fe - doped structures and their hydrogen molecule adsorptions are reported.

Gas adsorption on the Zn-, Pd- and Os-doped armchair (5,5) single-walled carbon nanotubes.

The adsorption of NO(2), NH(3), H(2)O, CO(2) and H(2) gases on the undoped, Zn-, Pd- and Os-doped armchair (5,5) single-walled carbon nanotubes (SWCNTs) were studied using density functional method. The adsorptions of these five gases on the Zn-, Pd- and Os-doped SWCNTs are obviously stronger than on the undoped SWCNT and their adsorption abilities are in the same order: NO(2) > NH(3) > H(2)O > CO(2) > H(2). Adsorption energies for all the studied gases on the undoped, Zn-, Pd- and Os-doped SWCNTs computed at the B3LYP/LanL2DZ level are reported.