A room-temperature titania-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination

TitleA room-temperature titania-nanotube hydrogen sensor able to self-clean photoactively from environmental contamination
Publication TypeJournal Article
Year of Publication2004
AuthorsMor, Gopal K., Carvalho Maria A., Varghese Ooman K., Pishko Michael V., and Grimes Craig A.
Refereed DesignationUnknown
JournalJournal of Materials Research
Volume19
Issue2
Pagination628?634
Date Published02/2004
ISSN0884-2914
DOI10.1557/jmr.2004.0079
Short TitleJournal of Materials Research
Citation Key161
Full Text

Abstract: described is a room-temperature hydrogen sensor comprised of a TiO2-nanotube array able to recover substantially from sensor poisoning through ultraviolet (UV) photocatalytic oxidation of the contaminating agent; in this case, various grades of motor oil. The TiO2 nanotubes comprising the sensor are a mixture of both anatase and rutile phases, having nominal dimensions of 22-nm inner diameter, 13.5-nm wall thickness, and 400-nm length, coated with a 10-nm-thick noncontinuous palladium layer. At 24°C, in response to 1000 ppm of hydrogen, the sensors show a fully reversible change in electrical resistance of approximately 175,000%. Cyclic voltammograms using a 1 N KOH electrolyte under 170 mW/cm2 UV illumination show, for both a clean and an oil-contaminated sensor, anodic current densities of approximately 28 mA/cm2 at 2.5 V. The open circuit oxidation potential shows a shift from 0.5 V to –0.97 V upon UV illumination.

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