Abstract
The CO sensing properties of a micro thermoelectric gas sensor (micro-TGS) with a double AuPtPd/SnO2 and Pt/α-Al2O3 catalyst were investigated. While several nanometer sized Pt and Pd particles were uniformly dispersed on SnO2, the Au particles were aggregated as particles measuring >10 nm in diameter. In situ diffuse reflectance Fourier transform Infrared spectroscopy (DRIFT) analysis of the catalyst showed a CO adsorption peak on Pt and Pd, but no clear peak corresponding to the interaction between CO and Au was detected. Up to 200 °C, CO combustion was more temperature dependent than that of H2, while H2 combustion was activated by repeated exposure to H2 gas during the periodic gas test. Selective CO sensing of the micro-TGS against H2 was attempted using a double catalyst structure with 0.3–30 wt% Pt/α-Al2O3 as a counterpart combustion catalyst. The sensor output of the micro-TGS decreased with increasing Pt content in the Pt/α-Al2O3 catalyst, by cancelling out the combustion heat from the AuPtPd/SnO2 catalyst. In addition, the AuPtPd/SnO2 and 0.3 wt% Pt/α-Al2O3 double catalyst sensor showed good and selective CO detection. We therefore demonstrated that our micro-TGS with double catalyst structure is useful for controlling the gas selectivity of CO against H2.
Highlights
Breath gas contains a range of marker gases that can be associated with disease and metabolism [1,2]
We propose a micro thermoelectric gas sensor, which uses the thermoelectric detection of a combustion catalyst, for monitoring H2 [3,4], CO [5,6,7], and CH4 [8,9] in human breath gas
As the addition of three noble metals to SnO2 appears to improve their sensitivity to volatile organic compounds (VOCs) [17,18], we attempted the incorporation of an AuPtPd/SnO2 combustion catalyst in our micro-TGS for CO detection
Summary
Breath gas contains a range of marker gases that can be associated with disease and metabolism [1,2]. Sakai and Itoh reported the sensing properties of Pt, Pd, and Au loaded on SnO2 (AuPtPd/SnO2) thick films as semiconductor-type gas sensors for volatile organic compounds (VOCs). As the addition of three noble metals to SnO2 appears to improve their sensitivity to VOCs [17,18], we attempted the incorporation of an AuPtPd/SnO2 combustion catalyst in our micro-TGS for CO detection. For CO and CH4, selectivity is lower, as a higher catalyst temperature is required for the oxidation of CO and CH4 In this context, we previously attempted to control CO and CH4 selectivity using a “double catalyst structure” [8,19]. The effects of the double catalyst structure containing a Pt/α-Al2O3 catalyst on the selective CO sensing properties of the micro-TGS are discussed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
