Highly Sensitive Room Temperature Hydrogen Sensors Based on Photochemically Deposited SnO2

2014 ◽  
Vol 787 ◽  
pp. 378-382 ◽  
Author(s):  
Masaya Ichimura ◽  
Dengbaoleer Ao

Highly sensitive room temperature hydrogen sensors based on undoped and Fe-doped SnO2 films were fabricated. The SnO2 films were deposited by the photochemical deposition using an aqueous solution containing SnSO4. For deposition of doped and undoped SnO2 films, a small amount of an aqueous solution was dropped on a glass substrate and irradiated by UV light. The sensors annealed at 200oC showed extremely high sensitivity to hydrogen, but the initial resistance was very high. The sensors annealed at 400oC had a much lower resistance, and thus the sensor response was able to be measured even by a pocket multimeter. The Fe-doped sample showed higher sensitivity compared with the undoped sample.

RSC Advances ◽  
2021 ◽  
Vol 11 (39) ◽  
pp. 23975-23984
Author(s):  
Xue Yang ◽  
Yixia Ren ◽  
Hongmei Chai ◽  
Xiufang Hou ◽  
Zhixiang Wang ◽  
...  

Four fluorescent 2D Zn-MOFs based on a flexible triangular ligand and linear N-donor ligands are hydrothermally prepared and used to detect nitrobenzene in aqueous solution with high sensitivity, demonstrating their potential as fluorescent sensors.


2019 ◽  
Vol 803 ◽  
pp. 120-123
Author(s):  
Xiong Bang Wei ◽  
Guo Dong Lv ◽  
Xiao Hui Yang ◽  
Tao Wu ◽  
Dong Shi ◽  
...  

In this paper, a kind of novel TiO2 nanotube arrays (TNTs) hybrid structure was presented to improve the performance of hydrogen sensors. In this novel structure, palladium functionalized TNTs hybrid nanostructure supported on titanium wire. TNTs arrays was prepared by anodizing Ti wire using a standard electrochemical procedure. Pd nanomaterials were deposited on TNTs. Optimized experiments showed the hydrogen sensor supported on titanium wire showed a good response time of 8 s and high sensitivity of 94.8% at 1.9 vol% H2 at room temperature (25 °C). The research work revealed potential good hydrogen sensitivity of this kind of hybrid nanostructure.


1994 ◽  
Vol 301 (1) ◽  
pp. 9-12 ◽  
Author(s):  
S Swillens ◽  
I Pirson

Several molecular mechanisms have been proposed to explain highly sensitive controls of cellular functions by effector molecules. Here we study an equilibrium model describing the regulation of transcriptional activity through the heterodimerization of transcription factors. We demonstrate that this model involves a new type of biochemical control which accounts for a very high sensitivity.


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.


2008 ◽  
Vol 1080 ◽  
Author(s):  
Xinpeng Wang ◽  
Jie Lou ◽  
Zhenbo Wang ◽  
Peter Xianping Feng

ABSTRACTTungsten oxide nanorod arrays deposited on the cylindrical substrate have been used for fabrication of a two-dimensional (2D) sensor. The sensibility and capacity towards methane and acetone at different temperatures have been examined. Experimental data have indicated that the newly designed sensor is highly sensitive to methane with low cross sensitivity towards possible mixed organic gas acetone, relying on the operating temperature. At room temperature (20°C), a quick response time and recovery time of the sensor, less than 10 ms, have been obtained.


2014 ◽  
Vol 29 (1) ◽  
pp. e55-e61 ◽  
Author(s):  
Francesca Messa ◽  
Federica Tonissi ◽  
Enrico Millo ◽  
Enrico Bracco ◽  
Silvana Ungari ◽  
...  

The detection of somatic mutations in a tumor represents a valuable tool for tumor characterization and provides the clinicians with information for setting up the most appropriate therapy. KRAS mutations in codons 12 and 13 are important biomarkers routinely analyzed in the clinic for the management of anti-EGFR treatment in colorectal carcinoma (CRC). Here we report a sensitive and inexpensive assay for KRAS mutations based on a PNA-mediated PCR clamping. The assay displays very high sensitivity (0.7%) and specificity (96.7%) when compared to traditional sequencing (SS) and pyrosequencing (PS), two of the most commonly and routinely used methods employed today by diagnostic laboratories. Furthermore, the PNA assay requires only basic and low-cost laboratory equipment, in contrast with all the most recent PCR-based technologies, which are highly sensitive but also much more expensive. Finally, despite the PNA assay does not allow for the definition of specific mutations, it is the cheapest and easiest screening method to firstly stratify wild-type and mutated patients, information that is strictly necessary to clinicians for the management of CRC and anti-EGFR treatment.


1978 ◽  
Vol 7 (5) ◽  
pp. 442-447
Author(s):  
A N Ponzi ◽  
A Pugliese ◽  
P Pertusio

Sensitivity to rubella virus hemagglutination differs considerably with newborn as opposed to adult erythrocytes (RBC) in several animal species. In humans, cord RBC are 16 times more sensitive to hemagglutination, whereas hemagglutination titers with newborn RBC are 6 to 16 times higher in chickens, mice, and rabbits. This higher sensitivity is, however, short-lived, and adult RBC values are observed 7 days after birth in mice. Trypsinization has no effect on newborn RBC, but increases sensitivity of adult RBC to that of neonatal RBC and tends to diminish differences among individuals. On the other hand, trypsinization does not further enhance the very high sensitivity of pigeon, duck, and goose RBC or the low sensitivity of both newborn and adult guinea pig RBC. Human cord RBC proved suitable for use in hemagglutination-inhibition tests, since they gave titers comparable to those obtained with other types of RBC and offered some advantages: by comparison with animal RBC, they did not require adsorption to remove nonspecific agglutinins; by comparison with adult human RBC, they did not need trypsinization.


2014 ◽  
Vol 3 (2) ◽  
pp. 273-280 ◽  
Author(s):  
T. Mazingue ◽  
M. Lomello-Tafin ◽  
M. Passard ◽  
C. Hernandez-Rodriguez ◽  
L. Goujon ◽  
...  

Abstract. Palladium platinum (PdPt) has been intensively studied these last decades due to high conversion rate in hydrogen oxidation at room temperature with significant exothermic effects. These remarkable properties have been studied by measuring the temperature variations of alumina (Al2O3) supported nanosized PdPt nanoparticles exposed to different hydrogen concentrations in dry air. This catalyst is expected to be used as a sensing material for stable and reversible ultrasensitive hydrogen sensors working at room temperature (low power consumption). Structural and gas sensing characterisations and catalytic activity of PdPt / Al2O3 systems synthesised by co-impregnation will be presented. Catalytic characterisations show that the system is already active at room temperature and that this activity sharply increases with rise in temperature. Moreover, the increase of the PdPt proportion in the co-impregnation process improves the activity, and very high conversion can be reached even at room temperature. The thermal response (about 3 °C) of only 1 mg of PdPt / Al2O3 is reversible, and the time response is about 5 s. The integration of PdPt / Al2O3 powder on a flat substrate has been realised by the deposition onto the powder of a thin porous hydrophobic layer of parylene. The possibility of using PdPt in gas sensors will be discussed.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 977
Author(s):  
Yuta Masuyama ◽  
Katsumi Suzuki ◽  
Akira Hekizono ◽  
Mitsuyasu Iwanami ◽  
Mutsuko Hatano ◽  
...  

The negatively charged nitrogen-vacancy (NV) center in diamonds is known as the spin defect and using its electron spin, magnetometry can be realized even at room temperature with extremely high sensitivity as well as a high dynamic range. However, a magnetically shielded enclosure is usually required to sense weak magnetic fields because environmental magnetic field noises can disturb high sensitivity measurements. Here, we fabricated a gradiometer with variable sensor length that works at room temperature using a pair of diamond samples containing negatively charged NV centers. Each diamond is attached to an optical fiber to enable free sensor placement. Without any magnetically shielding, our gradiometer realizes a magnetic noise spectrum comparable to that of a three-layer magnetically shielded enclosure, reducing the noises at the low-frequency range below 1 Hz as well as at the frequency of 50 Hz (power line frequency) and its harmonics. These results indicate the potential of highly sensitive magnetic sensing by the gradiometer using the NV center for applications in noisy environments such as outdoor and in vehicles.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xin Geng ◽  
Shuwei Li ◽  
Lalani Mawella-Vithanage ◽  
Tao Ma ◽  
Mohamed Kilani ◽  
...  

AbstractAtmospheric NO2 is of great concern due to its adverse effects on human health and the environment, motivating research on NO2 detection and remediation. Existing low-cost room-temperature NO2 sensors often suffer from low sensitivity at the ppb level or long recovery times, reflecting the trade-off between sensor response and recovery time. Here, we report an atomically dispersed metal ion strategy to address it. We discover that bimetallic PbCdSe quantum dot (QD) gels containing atomically dispersed Pb ionic sites achieve the optimal combination of strong sensor response and fast recovery, leading to a high-performance room-temperature p-type semiconductor NO2 sensor as characterized by a combination of ultra–low limit of detection, high sensitivity and stability, fast response and recovery. With the help of theoretical calculations, we reveal the high performance of the PbCdSe QD gel arises from the unique tuning effects of Pb ionic sites on NO2 binding at their neighboring Cd sites.


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