Here we report the highly effective detection of hydrogen sulfide
(H2S) gas by redox reactions based on single-walled carbon
nanotubes (SWCNTs) functionalized with
2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) as a catalyst and we also
discuss the important role of water vapor in the electrical
conductivity of SWCNTs during the sensing of H2S molecules.
To explore the H2S sensing mechanism, we investigate the
adsorption properties of H2S on carbon nanotubes (CNTs) and
the effects of the TEMPO functionalization using first-principles
density functional theory (DFT) and we summarize currentchanges of
devices resulting from the redox reactions in the presence of
H2S. The semiconducting-SWCNT (s-SWCNT) device
functionalized with TEMPO shows a very high sensitivity of 420% at 60%
humidity, which is 17 times higher than a bare s-SWCNT device under
dry conditions. Our results offer promising prospects for personal
safety and real-time monitoring of H2S gases with the
highest sensitivity and low power consumption and potentially at a low
cost.