First-principle study of SO2 adsorption on Fe/Co-doped vacancy defected single-walled (8,0) carbon nanotubes in sensor applications

To explore the excellent sensor for detecting the pollution gas SO2, the adsorptions of SO2 molecule on the surfaces of Fe/Co-doped carbon nanotubes (CNTs) and single vacancy defected (8, 0) CNTs were investigated by using density functional theory (DFT). In addition, the adsorption energies, geometries, energy gaps and electronic structures were analyzed. The results showed that Fe/Co-doping and single-vacancy-defected can improve the adsorption and sensitiveness of CNTs toward SO2. Considering the changes of energy gap before and after the SO2 molecule adsorbed on each modified CNTs and its adsorption strength, Fe-doped CNTs (Fe-CNTs) and Co-doped site-2 single-vacancy-defected CNTs performed better for detecting SO2 molecule. With the decreasing number of electrons of the doped atom (Fe, Co, Ni), the adsorption became more stable. The results of this paper are profound and meaningful for designing SO2 sensing devices.