Oxide Nanowires for Chemical Sensing
- PDF / 529,444 Bytes
- 7 Pages / 432 x 648 pts Page_size
- 61 Downloads / 250 Views
Oxide Nanowires for Chemical Sensing Zachary C. Caron1 Vivek N. Patel1 Dylan J. Meekins1 Michael J. Platek2 Otto J. Gregory1 1 2
Department of Chemical Engineering, University of Rhode Island, Kingston, RI 02881, U.S.A. Department of Electrical Engineering, University of Rhode Island, Kingston, RI 02881, U.S.A.
ABSTRACT With the recent terrorist attacks in Paris and the continued use of IED’s employing TATP for delivering these threats, there is a real need for explosives detection at trace levels. This work describes the fabrication and characterization of metal oxide nanowires used as catalysts for the detection of energetic materials at trace levels. Recently, several oxide nanowires, based on zinc oxide and copper oxide, have been incorporated into our solid-state gas sensors as catalysts. These nanowire catalysts produced a dramatic increase in sensor response with improved selectivity for threat molecules of interest. The improved responses were attributed to a large increase in surface area available for catalyst/analyte interaction. Zinc oxide and copper oxide nanowires were grown by hydrothermal and controlled oxidation reactions, and were characterized using XRD, XPS and SEM to determine extent of crystallinity, oxidation state and morphology. Results indicated that energetic materials such as TATP and 2-6 DNT could be detected at the part per billion level using these nanowire catalysts. Other oxide nanowires are being considered as catalysts for the detection of explosives and are discussed as well.
INTRODUCTION With the recent terrorist attacks in Paris and the use of IED’s employing TATP for delivery of these threats, as was the case in Paris, there is an urgent need for explosives detection at trace levels. Over the past few years, the detection of explosives has become a high priority for the Department of Homeland Security, especially the detection of explosives in the vapor phase. Current detection methods such as “drug-sniffing” dogs or IMS are not amenable for the continuous monitoring of explosives at low levels. We have demonstrated that our thermodynamic sensor [3] can detect explosives such as TATP, DNT and ammonium nitrate at trace levels in a single pass. The sensor relies on the catalytic decomposition of these energetic materials and the sensing of the heat affect associated with this decomposition as the molecules come into contact with a catalyst-coated microheater. By fabricating nanowire catalysts directly onto the microheater surface, tremendous gains in sensitivity and selectivity were achieved. The effective surface area of the catalyst was increased by several orders of magnitude by employing metal oxide nanowires instead of sputtered metal oxides. Ultimately, this lowered the detection limits to the ppb level for TATP and 2, 6-DNT. In some cases, the nanowires also served as a
1531 Downloaded from https:/www.cambridge.org/core. University of Illinois at Urbana - Champaign Library, on 06 Feb 2017 at 09:16:09, subject to the Cambridge Core terms of use, available at https:/www.
Data Loading...
