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Hydrogen sensing properties of protective-layer-coated single-walled carbon nanotubes with palladium nanoparticle decoration
Author(s)
Okabayashi, Y.
Minami, S.
Itabashi, K.
Ueda, T.
Shimazaki, R.
Ito, T.
Oura, K.
Honda, S.
Tabata, H.
Katayama, M.
Date Issued
February 4, 2011
Type
Article
Abstract
Protective-layer-coated single-walled carbon nanotubes (SWNTs) with palladium nanoparticle decoration (Pd-SiO2-SWNTs) were fabricated and their sensing properties for hydrogen (H2) were investigated. SWNTs were coated with a 3-4 nm thick SiO2 layer by pulsed laser deposition and subsequently decorated with Pd nanoparticles by electron beam evaporation. Even though the SWNTs were completely surrounded by a protective layer, Pd-SiO2-SWNTs responded to H2 down to a concentration of 1 part per million. Compared with the Pd nanoparticle-decorated SWNTs without a protective layer (Pd-SWNTs), Pd-SiO2-SWNTs exhibited highly stable sensor responses with variations of less than 20%; Pd-SWNTs showed a variation of 80%. The density of the Pd-SWNTs significantly decreased after the sensing test, while that of the Pd-SiO2-SWNTs with the netlike structure remained unchanged. The hydrogen sensing mechanism of the Pd-SiO 2-SWNTs was attributed to the chemical gating effect on the SWNTs due to dipole layer formation by hydrogen atoms trapped at the Pd-SiO2 interface. Moreover, the relationship between H2 concentration and sensor response can be described by the Langmuir isotherm for dissociative adsorption. © 2011 IOP Publishing Ltd.
Citation
Nanotechnology, 22(5), 2011