Tianshuang Wang,Wei Tao,Xueying Kou,Liupeng Zhao,Peng Sun,Geyu Lu
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 (Sacetone at 80% RH > Sacetone at 5% RH). These demonstrations offer crucial insight into the precise design of highly efficient overlayers for breath sensing.
Polyimide nanofiber aerogels loaded with thymol blue and hydroxylamine sulfate (TB-HAS@PI NFAs) were synthesized and employed as a novel sensor for colorimetric detection of breath acetone (BrAce). The enhancement of 3D multi-level pore structure of TB-HAS@PI NFAs for sensing performance was elucidated through systematical characterization results. Because the designed sensing system relied on the specific reaction of HAS with acetone, TB-HAS@PI NFAs exhibited a more sensitive response ability to acetone, ensuring that the colorimetric sensing detection will not be interfered by other coexisting gas in exhaled breath. Moreover, the sensor demonstrated a rapid response, with color changes quantitatively measured within 30 s of exposure to acetone gas. Importantly, the feasibility and accuracy of established method were confirmed through comparison with GC–MS. This research provided a promising strategy for daily health management of healthy people and diabetics.
危险品化学品经营许可证（带存储）