Detection of hydrogen using multi-walled carbon-nanotube yarns coated with nanocrystalline Pd and Pd/Pt layered structures

Author:

Randeniya, Lakshman; Martin, Phil; Bendavid, Avi

Date of Publication:

2012-04-02

Publication Type:

Journal Article

Journal Title:

Carbon

Volume:

50

Issue:

5

Pages:

1786-1792

Abstract:

Chemiresistors fabricated from multi-walled carbon nanotube yarns decorated with nanocrystalline Pd (Pd-MWCNT) have been used to detect hydrogen from 20 ppm to 2% in nitrogen at room temperature. In the case of chemiresistors fabricated by seeding a Pd layer with smaller nano islands of Pt (Pd-Pt-MWCNT), the dynamic range was extended further from 5 ppm to 3%. Concentrations of hydrogen above 2 % and 3 % were detectable but the sensitivity saturated above these levels. It is shown that the sensitivity to hydrogen is a resultant of two mechanisms which leads to opposing changes in resistance in the composite yarns. A clear deviation from the Sievert’s law is observed at concentrations above 100 ppm and is attributed to the presence of these competing mechanisms. The sensitivity is reduced for hydrogen when the experiments were carried out in dry air and the lower limit of detection was found to be 2000 ppm for Pd-MWCNT chemiresistor and 400 ppm for Pd-Pt-MWCNT chemiresistor. Pd-Pt-MWCNT chemiresistor showed excellent response and recovery characteristics in air. For Pd-MWCNT chemiresistor, the nanoscopic gap closing mechanism became prominent at concentrations below ~ 1000 ppm and allowed the detection of hydrogen down to 200 ppm in air using negative changes in resistance. This is the first time such large dynamic ranges for hydrogen detection is reported for composites of metals with MWCNT.

Publisher:

Elsevier

Keywords:

Multiwalled carbon nano tubes; noncrystalline metals; hydrogen; chemiresistor; sensor; Palladium; Platinum

Field Of Research:

Physical Sciences not elsewhere classified

Full Text Availability:

Submitted to Publisher (pdf) (366KB)

DOI:

https://doi.org/10.1016/j.carbon.2011.12.026

URL:

Link to Publisher's Version

Rights Notice:

©2012, Elsevier. NOTICE: this is the author’s version of a work that was accepted for publication in Carbon. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Carbon, Volume 50, Issue 5, April 2012, Pages 1786–1792, DOI: 10.1016/j.carbon.2011.12.026

Identifier:

EP115973

Publication Sub Type:

Journal article - Refereed

Language:

English

Attribution Statement:

Randeniya, Lakshman; Martin, Phil; Bendavid, Avi. Detection of hydrogen using multi-walled carbon-nanotube yarns coated with nanocrystalline Pd and Pd/Pt layered structures. Carbon. 2012; 50(5):1786-1792. https://doi.org/10.1016/j.carbon.2011.12.026