Effect of acid pretreatment on the sensitivity of gas sensors based on single-walled carbon nanotube bundles

In this paper, the effect of acid pretreatment on the structure and the composition of single-walled carbon nanotube (SWNT) bundles is presented. The change in the sensitivity of gas sensors based on SWNT bundles with various treatments to hydrogen sulfide (H2S) exposures is also reported. The experimental results revealed that acid pretreatment not only purified the SWNT by removing the catalytic particles from the SWNT bundles but also caused fragmentation of the SWNT bundles and enlargement of the SWNT diameter, thereby improving the sensitivity of the SWNT-based sensor. After a 30-min exposure to 50-ppm H₂S at room temperature, the resistances of the non-treated and the 4h-stirred sensors increased 12 % and 38 % respectively, in comparison with their initial values. These findings open a promising direction in the development of SWNT-based gas sensors.