| Jan 30, 2026 |
A new gas sensor using ruthenium dioxide nanosheets achieves ultra-sensitive ethanol detection down to 5 ppb, enabling real-time breath alcohol monitoring at under 30 milliwatts.
(Nanowerk News) Ethanol is widely used in industrial processing, food production, medical diagnostics, and transportation, but its volatility and potential health risks demand reliable monitoring at low concentrations. Conventional metal-oxide gas sensors are attractive because of their simplicity and low cost, yet they typically require high operating temperatures and show limited sensitivity or poor selectivity at trace ethanol levels.
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Environmental humidity and signal instability further complicate real-world deployment. Improving sensor performance therefore requires new material strategies that can accelerate surface reactions while amplifying electrical responses without increasing power consumption. Based on these challenges, it is necessary to conduct in-depth research into advanced functional materials that can fundamentally enhance ethanol gas sensing performance.
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Researchers from Yonsei University and collaborating institutions reported this advance in Microsystems & Nanoengineering (“Ultra-sensitive ethanol detection using a chemiresistive SnO2 thin-film gas sensor functionalized with RuO2 nanosheets”).
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| Real-time monitoring of exhaled breath ethanol concentration using the sensor. (Image: Reproduced from DOI:10.1038/s41378-025-01055-6, CC BY)
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The team designed a microheater-integrated gas sensor in which ultrathin ruthenium dioxide nanosheets were deposited onto a tin dioxide thin film. This hybrid structure enabled ultra-sensitive ethanol detection across a wide concentration range, including parts-per-billion levels, while operating at low power. Beyond laboratory testing, the sensor also demonstrated real-time tracking of breath alcohol concentration, highlighting its potential for practical safety and health-related applications.
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The core innovation lies in functionalizing a traditional tin-oxide sensing layer with monolayer-scale ruthenium dioxide nanosheets. These nanosheets provide an exceptionally high surface-to-volume ratio and strong catalytic activity, which together accelerate ethanol oxidation reactions on the sensor surface.
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At the same time, electronic interactions at the interface between the two materials create an expanded electron depletion layer, amplifying resistance changes when ethanol is present. As a result, the sensor’s response to ethanol increased by more than threefold compared with an unmodified device.
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The sensor was fabricated on a suspended membrane platform incorporating a microheater, minimizing heat loss and enabling continuous operation below 30 milliwatts. Systematic testing showed reliable detection from 10 parts per million down to approximately 5 parts per billion, placing the device among the most sensitive chemiresistive ethanol sensors reported to date.
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The sensor also exhibited improved selectivity against common interfering gases, stable operation over nearly a month, and reproducible performance across repeated sensing cycles. Importantly, controlled experiments demonstrated that the device could track dynamic changes in breath alcohol concentration in real time, closely matching readings from a commercial breathalyzer.
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“This work shows how nanoscale material engineering can fundamentally change the performance limits of conventional gas sensors,” the researchers noted. By leveraging both catalytic and electronic sensitization effects, the design achieves a rare combination of ultra-high sensitivity, low power consumption, and operational stability. They emphasized that the integration of nanosheets onto a scalable thin-film platform makes the approach compatible with existing microfabrication technologies, which is essential for translating laboratory advances into practical sensing devices.
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The ultra-sensitive ethanol sensor has implications well beyond laboratory demonstrations. In industrial environments, it could provide early warnings of ethanol leaks or vapor buildup, improving fire prevention and worker safety. In healthcare and transportation, compact and low-power sensors could enable next-generation breath analyzers for real-time alcohol monitoring, supporting medical diagnostics and drunk-driving prevention systems.
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More broadly, the nanosheet-functionalization strategy can be extended to other target gases, offering a versatile pathway for developing high-performance sensors for environmental monitoring, smart infrastructure, and wearable health technologies.
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