Carbon-nanotube doping is extensively researched. This work aims to investigate a novel sensor for detecting the five gas components of SF6 decomposition (i.e., SO2, H2S, SOF2, SO2F2, and CF4) using Pddoped zigzag (8,0) single-wall carbon nanotubes (Pd-SWCNTs). We compute the preferential adsorption sites, bonding configurations, and adsorption geometry for molecular adsorption. Results of electrical characteristics analysis reveal that Pd-SWCNTs show different responses to the five gases. After SO2, H2S, and SOF2 adsorbed onto Pd-SWCNTs, the conductivity of Pd-SWCNTs increases in the following order: SO2 > SOF2 > H2S. SO2F2 adsorption onto Pd-SWCNTs slightly decreases conductivity. Conversely, Pd-SWCNTs are not sensitive to the other gas molecule CF4. We conclude that Pd-SWCNTs have good sensitivity and selectivity to SO2, H2S, SOF2, SO2F2, and CF4. (C) 2014 Elsevier B.V. All rights reserved.