Computational study of B- or N-doped single-walled carbon nanotubes as NH3 and NO2 sensors

The adsorption of NH3 and NO2 in B- or N-doped (10, 0) single-walled carbon nanotubes (SWCNTs) was investigated by using density functional computations to exploit their potential applications as gas sensors. NH3 can be chemisorbed only in B-doped SWCNTs with apparent charge transfer, so B-doped SWCNTs can be used as NH3 sensors. Both B- and N-doping make NO2 chemisorption feasible in SWCNTs, but the binding of NO2 with B is too strong, indicating an impractical recovery time as gas sensors. Due to the medium (optimal) adsorption energy and the conductance reduction accompanied with the charge transfer between SWCNTs and gas molecules, N-doped SWCNTs are potentially good NO2 sensors.