scholarly journals Highly sensitive and room temperature detection of ultra-low concentrations of O3 using self-powered sensing elements of Cu2O nanocubes

2019 ◽  
Vol 1 (5) ◽  
pp. 2009-2017 ◽  
Author(s):  
E. Petromichelaki ◽  
E. Gagaoudakis ◽  
K. Moschovis ◽  
L. Tsetseris ◽  
T. D. Anthopoulos ◽  
...  

The fundamental development of the design of novel self-powered ozone sensing elements, operating at room temperature, based on p-type metal oxides paves the way to a new class of low cost, highly promising gas sensing devices.

2019 ◽  
Vol 288 ◽  
pp. 625-633 ◽  
Author(s):  
Hwan-Seok Jeong ◽  
Min-Jae Park ◽  
Soo-Hun Kwon ◽  
Hyo-Jun Joo ◽  
Hyuck-In Kwon

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu-Sung Chang ◽  
Feng-Kuan Chen ◽  
Du-Cheng Tsai ◽  
Bing-Hau Kuo ◽  
Fuh-Sheng Shieu

AbstractIn this study, we use nitrogen-doped to improving the gas-sensing properties of reduced graphene oxide. Graphene oxide was prepared according to a modified Hummers’ method and then nitrogen-doped reduced graphene oxide (N-rGO) was synthesized by a hydrothermal method using graphene oxide and NH4OH as precursors. The rGO is flat and smooth with a sheet-like morphology while the N-rGO exhibits folded morphology. This type of folding of the surface morphology can increase the gas sensitivity. The N-rGO and the rGO sensors showed n-type and p-type semiconducting behaviors in ambient conditions, respectively, and were responsive to low concentrations of NO gases (< 1000 ppb) at room temperature. The gas-sensing results showed that the N-rGO sensors could detect NO gas at concentrations as low as 400 ppb. The sensitivity of the N-rGO sensor to 1000 ppb NO (1.7) is much better than that of the rGO sensor (0.012). Compared with pure rGO, N-rGO exhibited a higher sensitivity and excellent reproducibility.


Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6475
Author(s):  
Jiahui Guo ◽  
Weiwei Li ◽  
Xuanliang Zhao ◽  
Haowen Hu ◽  
Min Wang ◽  
...  

Semiconducting metal oxides can detect low concentrations of NO2 and other toxic gases, which have been widely investigated in the field of gas sensors. However, most studies on the gas sensing properties of these materials are carried out at high temperatures. In this work, Hollow SnO2 nanofibers were successfully synthesized by electrospinning and calcination, followed by surface modification using ZnO to improve the sensitivity of the SnO2 nanofibers sensor to NO2 gas. The gas sensing behavior of SnO2/ZnO sensors was then investigated at room temperature (~20 °C). The results showed that SnO2/ZnO nanocomposites exhibited high sensitivity and selectivity to 0.5 ppm of NO2 gas with a response value of 336%, which was much higher than that of pure SnO2 (13%). In addition to the increase in the specific surface area of SnO2/ZnO-3 compared with pure SnO2, it also had a positive impact on the detection sensitivity. This increase was attributed to the heterojunction effect and the selective NO2 physisorption sensing mechanism of SnO2/ZnO nanocomposites. In addition, patterned electrodes of silver paste were printed on different flexible substrates, such as paper, polyethylene terephthalate and polydimethylsiloxane using a facile screen-printing process. Silver electrodes were integrated with SnO2/ZnO into a flexible wearable sensor array, which could detect 0.1 ppm NO2 gas after 10,000 bending cycles. The findings of this study therefore open a general approach for the fabrication of flexible devices for gas detection applications.


2013 ◽  
Vol 543 ◽  
pp. 422-425
Author(s):  
Huan Liu ◽  
Min Li ◽  
Jiu Xiao Wan ◽  
Jun Zhao ◽  
Qiu Yun Fu ◽  
...  

High-quality SnO2 thin-film materials capable of detecting H2S gas of low concentrations at room temperature was demonstrated in this paper. We employed aerosol-assisted chemical vapor deposition process for the deposition of SnO2 thin films on alumina substrates with pre-patterned electrodes. The gas-sensing performances of the films prepared under different deposition conditions were systematically compared and analyzed. When SnCl2·2H2O was used as the precursor, a response sensitivity of 98.4 toward 50 ppm of H2S at room temperature was achieved. At room temperatures, the resistance upon the H2S gas exposure could recover to 90% of the initial resistance of the sensor when the H2S gas flow was turned off.


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 303
Author(s):  
Hui Zhou ◽  
Kai Xu ◽  
Nam Ha ◽  
Yinfen Cheng ◽  
Rui Ou ◽  
...  

Reversible H2 gas sensing at room temperature has been highly desirable given the booming of the Internet of Things (IoT), zero-emission vehicles, and fuel cell technologies. Conventional metal oxide-based semiconducting gas sensors have been considered as suitable candidates given their low-cost, high sensitivity, and long stability. However, the dominant sensing mechanism is based on the chemisorption of gas molecules which requires elevated temperatures to activate the catalytic reaction of target gas molecules with chemisorbed O, leaving the drawbacks of high-power consumption and poor selectivity. In this work, we introduce an alternative candidate of cobalt oxysulfide derived from the calcination of self-assembled cobalt sulfide micro-cages. It is found that the majority of S atoms are replaced by O in cobalt oxysulfide, transforming the crystal structure to tetragonal coordination and slightly expanding the optical bandgap energy. The H2 gas sensing performances of cobalt oxysulfide are fully reversible at room temperature, demonstrating peculiar p-type gas responses with a magnitude of 15% for 1% H2 and a high degree of selectivity over CH4, NO2, and CO2. Such excellent performances are possibly ascribed to the physisorption dominating the gas–matter interaction. This work demonstrates the great potentials of transition metal oxysulfide compounds for room-temperature fully reversible gas sensing.


Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3815
Author(s):  
Renyun Zhang ◽  
Magnus Hummelgård ◽  
Joel Ljunggren ◽  
Håkan Olin

Metal-semiconductor junctions and interfaces have been studied for many years due to their importance in applications such as semiconductor electronics and solar cells. However, semiconductor-metal networks are less studied because there is a lack of effective methods to fabricate such structures. Here, we report a novel Au–ZnO-based metal-semiconductor (M-S)n network in which ZnO nanowires were grown horizontally on gold particles and extended to reach the neighboring particles, forming an (M-S)n network. The (M-S)n network was further used as a gas sensor for sensing ethanol and acetone gases. The results show that the (M-S)n network is sensitive to ethanol (28.1 ppm) and acetone (22.3 ppm) gases and has the capacity to recognize the two gases based on differences in the saturation time. This study provides a method for producing a new type of metal-semiconductor network structure and demonstrates its application in gas sensing.


2015 ◽  
Vol 119 (52) ◽  
pp. 29186-29192 ◽  
Author(s):  
Ruey-Chi Wang ◽  
Yu-Xian Lin ◽  
Jia-Jun Wu

2021 ◽  
pp. 130954
Author(s):  
Jiahong Tang ◽  
Hao Wang ◽  
Xiaoxia Wang ◽  
Changsheng Xie ◽  
Dawen Zeng

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 626
Author(s):  
Seokhun Kwon ◽  
Seokwon Lee ◽  
Joouk Kim ◽  
Chulmin Park ◽  
Hosung Jung ◽  
...  

Recently, as air pollution and particulate matter worsen, the importance of a platform that can monitor the air environment is emerging. Especially, among air pollutants, nitrogen dioxide (NO2) is a toxic gas that can not only generate secondary particulate matter, but can also derive numerous toxic gases. To detect such NO2 gas at low concentration, we fabricated a GNWs/NiO-WO3/GNWs heterostructure-based gas sensor using microwave plasma-enhanced chemical vapor deposition (MPECVD) and sputter, and we confirmed the NO2 detection characteristics between 10 and 50 ppm at room temperature. The morphology and carbon lattice characteristics of the sensing layer were investigated using field emission scanning electron microscopy (FESEM) and Raman spectroscopy. In the gas detection measurement, the resistance negative change according to the NO2 gas concentration was recorded. Moreover, it reacted even at low concentrations such as 5–7 ppm, and showed excellent recovery characteristics of more than 98%. Furthermore, it also showed a change in which the reactivity decreased with respect to humidity of 33% and 66%.


2019 ◽  
Vol 285 ◽  
pp. 92-107 ◽  
Author(s):  
Ioannis Kortidis ◽  
Hendrik C. Swart ◽  
Suprakas Sinha Ray ◽  
David E. Motaung

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