Highly Selective and Robust SWNT Hybrid Sensor for Hydrogen Sulphide Detection

H.Y. Jung, Y.L. Kim, S. Park, A. Datar, H–J Lee, J. Huang, S. Somu, A. Busnaina, Y.J. Jung, Y–K Kwon
Center for High-rate Nanomanufacturing, US

Keywords: carbon nanotubes, conductance based sensors

Summary:

Hydrogen sulfide (H2S) is a toxic gas that causes asphyxiation, lung damage, and teratogenic effects when humans are exposed to it even in low doses. H2S is widely present in natural gas, petroleum and mines and is also given off as a by-product during certain manufacturing processes. To monitor H2S instantaneously for ensuring worker’s safety, we have fabricated and tested a reusable, low-power consuming conductance-based sensor based on TEMPO functionalized, semiconducting single-walled carbon nanotubes (s-SWCNTs). Highly organized s-SWCNT networks serving as channel in these sensors were fabricated through a CHN-developed offset printing process, and non-covalent functionalization is used to attach the TEMPO to the s-SWCNTs. These instantaneous sensors exhibit excellent sensitivity (detection limit down to ppm levels) with high specificity. We show that these sensors can withstand 200 C temperature and 25 KPsi pressure with minimal impact on detection capability. Using first-principles density functional theory (DFT) we investigate the adsorption properties of H2S on CNTs, the effects of TEMPO functionalization, and the current change in devices resulting from redox reactions in the presence of H2S. The s-SWCNT device functionalized with TEMPO shows a very high sensitivity of 420% at 60% humidity, 17 times higher than bare s-SWCNTs.