SnO2: A comprehensive review on structures and gas sensors

Xin Zhou,†,‡ Songyi Lee,† Zhaochao Xu,* and Juyoung Yoon*,† †Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 120-750, Republic of Korea ‡Research Center for Chemical Biology, Department of Chemistry, Yanbian University, Yanjii 133002, People’s Republic of China Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Shahekou, Dalian, Liaoning, People’s Republic of China

Recent Progress on the Development of Chemosensors for Gases.

Breath analysis by nanostructured metal oxides as chemo-resistive gas sensors

Sensitive detection of acetone and hydrogen sulfide levels in exhaled human breath, serving as breath markers for some diseases such as diabetes and halitosis, may offer useful information for early diagnosis of these diseases. Exhaled breath analyzers using semiconductor metal oxide (SMO) gas sensors have attracted much attention because they offer low cost fabrication, miniaturization, and integration into portable devices for noninvasive medical diagnosis. However, SMO gas sensors often display cross sensitivity to interfering species. Therefore, selective real-time detection of specific disease markers is a major challenge that must be overcome to ensure reliable breath analysis. In this work, we report on highly sensitive and selective acetone and hydrogen sulfide detection achieved by sensitizing electrospun SnO2 nanofibers with reduced graphene oxide (RGO) nanosheets. SnO2 nanofibers mixed with a small amount (0.01 wt %) of RGO nanosheets exhibited sensitive response to hydrogen sulfide (Rair/Rgas ...

Selective Detection of Acetone and Hydrogen Sulfide for the Diagnosis of Diabetes and Halitosis Using SnO2 Nanofibers Functionalized with Reduced Graphene Oxide Nanosheets

Solid-state gas sensors for breath analysis: a review.

Thin-walled WO3 hemitubes and catalytic Pt-functionalized WO3 hemitubes were synthesized via a polymeric fiber-templating route and used as exhaled breath sensing layers for potential diagnosis of halitosis and diabetes through the detection of H2S and CH3COCH3, respectively. Pt-functionalized WO3 hemitubes with wall thickness of 60 nm exhibited superior acetone sensitivity (Rair/Rgas = 4.11 at 2 ppm) with negligible H2S response, and pristine WO3 hemitubes showed a 4.90-fold sensitivity toward H2S with minimal acetone-sensing characteristics. The detection limit (Rair/Rgas) of the fabricated sensors with Pt-functionalized WO3 hemitubes was 1.31 for acetone of 120 ppb, and pristine WO3 hemitubes showed a gas response of 1.23 at 120 ppb of H2S. Long-term stability tests revealed that the remarkable selectivity has been maintained after aging for 7 months in air. The superior cross-sensitivity and response to H2S and acetone gas offer a potential platform for application in diabetes and halitosis diagnosis.

Selective Diagnosis of Diabetes Using Pt-Functionalized WO3 Hemitube Networks As a Sensing Layer of Acetone in Exhaled Breath

We report on facile synthesis of SnO 2 nanofibers (NFs) functionalized by Pt nanoparticles (NPs) with various loading contents (0.05–0.4 wt%) and their gas response toward H 2 , NO 2 , NH 3 , CO, and SO 2 gases as a function of the operation temperature (100–450 °C) and gas concentration (0.125–2.5 ppm). Mesoporous SnO 2 NFs with large surface-to-volume ratio, which facilitates sensitive gas response, were synthesized by electrospinning followed by subsequent calcination at 500 °C for 2 h. Colloidal Pt NPs synthesized by simple polyol method were immobilized on SnO 2 NFs as a catalytic sensitizer to H 2 oxidation. The gas sensing properties and response kinetics were significantly affected by the Pt NPs and the operation temperature. It was found that 0.1 wt% Pt-loaded SnO 2 sensor showed the highest H 2 response ( I gas / I air  = 16.6 at 2.5 ppm) at 300 °C. A remarkably high NO 2 response ( I air / I gas  = 57.0 at 2.5 ppm) was achieved in the case of pristine SnO 2 sensor at 150 °C. This work demonstrates that sensitive and selective detection of H 2 and NO 2 gases with negligible cross-response to interfering gases such as NH 3 , CO, and SO 2 can be obtained by decoration with Pt NPs on metal oxide NFs in conjunction with manipulation of the operation temperature.

Bong-Hoon Jang

Papers

Selective Diagnosis of Diabetes Using Pt-Functionalized WO3 Hemitube Networks As a Sensing Layer of Acetone in Exhaled Breath

Selectivity enhancement of SnO2 nanofiber gas sensors by functionalization with Pt nanocatalysts and manipulation of the operation temperature