Abstract

Constructing a bilayer structure has not been reported as a method to mitigate the adverse effect of water poisoning on oxide chemiresistors while simultaneously enhancing gas selectivity and sensitivity. To address this challenge, pyrochlore-Bi2Sn2O7 has been first utilized as an overlayer on a ZnO sensing layer for constructing a bilayer acetone chemiresistor, leading to remarkable improvement in the performance for trace-level (500 p-p-b) acetone detection under high humidity (80% relative humidity). In addition, owing to the catalytic predecompositions of ethanol across the overlayer, an outstanding acetone gas selectivity (Sacetone/Sethanol = 2.9) has been achieved, with a more than 4-fold improvement compared with monolayer ZnO chemiresistor (Sacetone/Sethanol = 0.7). More significantly, comprehensive experiments coupled with in situ characterizations have verified the generation of hydroxyl radicals (•OH) on the Bi2Sn2O7 overlayer. These radicals are capable of enhancing the kinetics between •OH and acetone, reducing the activation energy required for the gas sensing reaction, and thus leading to an unexpected phenomenon of enhanced acetone sensitivity under high humid conditions (Sacetoneat80%RH > Sacetoneat5%RH). These demonstrations offer crucial insight into the precise design of highly efficient overlayers for breath sensing.

Full Text

Published Version

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 call

Disclaimer: 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.