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Room-temperature hydrogen sensor based on palladium nanowires | IEEE Journals & Magazine | IEEE Xplore

Room-temperature hydrogen sensor based on palladium nanowires


Abstract:

Palladium (Pd) nanowires, synthesized by template-nanomanufacturing techniques, has been studied for hydrogen gas-sensing applications at room temperature. In this study,...Show More

Abstract:

Palladium (Pd) nanowires, synthesized by template-nanomanufacturing techniques, has been studied for hydrogen gas-sensing applications at room temperature. In this study, parallel arrays of Pd nanowires were fabricated by electrodeposition from an aqueous plating solution onto the surface of highly oriented pyrolytic graphite (HOPG). The nanowires were then transferred onto a polystyrene film and silver electrical contact pads were fabricated by shadow masking. The morphology of the nanowires was analyzed using atomic force microscope (AFM) in noncontact mode and the diameter of the observed nanowires was measured to be approximately 250 nm. Scanning electron microscope (SEM) images revealed that the nanowires fabricated by this procedure were parallel and continuous. Electrodes were patterned by shadow masking and the I-V characteristics of the nanowires were studied. Experimental results indicated that the sensors are highly sensitive to hydrogen, showing a two-order change in conductance. The morphology of the nanowires was analyzed using SEM and AFM in order to understand the properties responsible for the high sensitivity of the nanowires. SEM images showed that the nanowires contain nanogaps in absence of H/sub 2/. Upon exposure to H/sub 2/, the Pd absorbed hydrogen, resulting in the expansion of Pd grains. This expansion results in the closing of the nanogaps. The expansion occurred due to the phase transition from /spl alpha/ to /spl beta/ and the Pd lattice expansion.
Published in: IEEE Sensors Journal ( Volume: 5, Issue: 5, October 2005)
Page(s): 792 - 797
Date of Publication: 06 September 2005

ISSN Information:


I. Introduction

Nanosized materials have gained much interest for fabricating new conductor gas sensors due to their great surface activity. Silicon nanowires [1]–[3], single-wall carbon nanotubes (SWNTs) [4]–[8], and metal–oxide nanowires [9], [10] have been used to fabricate highly sensitive and selective sensors for detection of chemical and biological species. sensors are being actively studied [11], [12] and have many applications in the fields of space launch vehicles, industrial leak detection, and automobile fuel additives.

References

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