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Joule Heating a Palladium Nanowire Sensor for Accelerated Response and Recovery to Hydrogen Gas
Author(s) -
Yang Fan,
Taggart David K.,
Penner Reginald M.
Publication year - 2010
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201000145
Subject(s) - nanowire , materials science , palladium , hydrogen , joule heating , electrical resistance and conductance , analytical chemistry (journal) , nanotechnology , chemistry , composite material , catalysis , organic chemistry
The properties of a single heated palladium (Pd) nanowire for the detection of hydrogen gas (H 2 ) are explored. In these experiments, a Pd nanowire, 48–98 µm in length, performs three functions in parallel: 1) Joule self‐heating is used to elevate the nanowire temperature by up to 128 K, 2) the 4‐contact wire resistance in the absence of H 2 is used to measure its temperature, and 3) the nanowire resistance in the presence of H 2 is correlated with its concentration, allowing it to function as a H 2 sensor. Compared with the room‐temperature response of a Pd nanowire, the response of the heated nanowire to hydrogen is altered in two ways: First, the resistance change (ΔR/ R 0 ) induced by H 2 exposure at any concentration is reduced by a factor of up to 30 and second, the rate of the resistance change – observed at the beginning (“response”) and at the end (“recovery”) of a pulse of H 2 – is increased by more than a factor of 50 at some H 2 concentrations. Heating nearly eliminates the retardation of response and recovery seen from 1–2% H 2 , caused by the α → β phase transition of PdH x , a pronounced effect for nanowires at room temperature. The activation energies associated with sensor response and recovery are measured and interpreted.