Environmentally hazardous gas sensing ability of MoS(2)-nanotubes: an insight from the electronic structure and transport properties

Herein we have investigated the ability of the (6,6) MoS(2)-nanotube (NT) to sense environmentally hazardous electrophilic and nucleophilic gases using density functional theory (DFT). CO, CO(2), H(2)O and NH(3) gases were chosen for adsorption on the (6,6) MoS(2)-NT and different adsorption parameters such as adsorption energy, projected density of states (PDOS), band structure and structural changes after adsorption were evaluated. Nucleophilic gases NH(3) and H(2)O showed a fairly high amount of electron density transfer from gas molecules to the NT while the opposite trend was realized for electrophilic gases CO and CO(2). Among the four gases, H(2)O has the highest amount of adsorption energy (−1.74 eV) and a moderately high amount of charge transfer from H(2)O to the NT. Gas sensing behaviour was further rationalized from the enhanced I–V characteristics of gas adsorbed nanotubes compared to pristine ones. Analysis of results revealed that the (6,6) MoS(2)-NT showed a decent level of gas sensing properties towards CO, CO(2), H(2)O and NH(3) gases, and high selectivity for H(2)O makes the MoS(2)-NT superior to previously reported MoS(2)-monolayer in this matter. These results suggest the possibility of fabrication of highly efficient MoS(2)-NT based gas sensors for environmentally hazardous gases.