The adsorption of certain hydrocarbon gases (C2H2, C2H4, and C2H6) on Fe-doped and Fe-decorated SWCNTs have been researched using Density Functional Theory (DFT) calculations. Three Fe-decorated SWCNT configurations, which are bridge, hollow, and top position of Fe on SWCNT, were calculated to discover the highest energy interaction. The Fe on the hollow configuration was found to be the most stable configuration. The results also show that Fe-decorated SWCNT has stronger adsorption energy than Fe doped SWCNT. Based on geometry structure and adsorption energy, Fe-SWCNT has the best sensitivity for C2H2 compared to C2H4 and C2H6. The adsorption energy order from the highest to the lowest is C2H2< C2H4 < C2H6.
