Gas Sensing Properties of TiO2 and SnO2 Nanopowders Obtained through Gel Combustion

2006 ◽  
Vol 45 ◽  
pp. 1828-1833
Author(s):  
Fabio A. Deorsola ◽  
P. Mossino ◽  
Ignazio Amato ◽  
Bruno DeBenedetti ◽  
A. Bonavita ◽  
...  
Keyword(s):  
Response Time ◽  
Metal Oxides ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Fast Response ◽  
High Specific Surface Area ◽  
Research Field ◽  
Wide Range ◽  
Gel Combustion

Nanostructured semiconductor metal oxides have played a central role in the gas sensing research field, because of their high sensitivity, selectivity and low response time. Among all the processes, developed for the synthesis of nanostructured metal oxides, gel combustion seems to be the most promising route due to low-cost precursors and simplicity of the process. It combines chemical gelation and combustion, involving the formation of a gel from an acqueous solution and an exothermic redox reaction, yielding to very porous and softly agglomerated nanopowders. In this work, nanostructured tin oxide, SnO2, and titanium oxide, TiO2, have been synthesized through gel combustion. Powders showed nanometric particle size and high specific surface area. The so-obtained TiO2 and SnO2 nanopowders have been used as sensitive element of resistive λ sensor and ethanol sensor respectively, realized depositing films of nanopowders dispersed in water onto alumina substrates provided with Pt contacts and heater. TiO2-based sensors showed at high temperature good response, fast response time, linearity in a wide range of O2 concentration and long-term stability. SnO2-based sensors have shown high sensitivity to low concentrations of ethanol at moderate temperature.

scholarly journals Embedded Transdermal Alcohol Detection via a Finger Using SnO2 Gas Sensors

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6852
Author(s):  
Fatima Ezahra Annanouch ◽  
Virginie Martini ◽  
Tomas Fiorido ◽  
Bruno Lawson ◽  
Khalifa Aguir ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Rf Magnetron Sputtering ◽  
Alcohol Concentration ◽  
Invasive Technique ◽  
Clear Correlation ◽  
Wide Range

In this paper, we report the fabrication and characterization of a portable transdermal alcohol sensing device via a human finger, using tin dioxide (SnO2) chemoresistive gas sensors. Compared to conventional detectors, this non-invasive technique allowed us the continuous monitoring of alcohol with low cost and simple fabrication process. The sensing layers used in this work were fabricated by using the reactive radio frequency (RF) magnetron sputtering technique. Their structure and morphology were investigated by means of X-ray spectroscopy (XRD) and scanning electron microscopy (SEM), respectively. The results indicated that the annealing time has an important impact on the sensor sensitivity. Before performing the transdermal measurements, the sensors were exposed to a wide range of ethanol concentrations and the results displayed good responses with high sensitivity, stability, and a rapid detection time. Moreover, against high relative humidity (50% and 70%), the sensors remained resistant by showing a slight change in their gas sensing performances. A volunteer (an adult researcher from our volunteer group) drank 50 mL of tequila in order to realize the transdermal alcohol monitoring. Fifteen minutes later, the volunteer’s skin started to evacuate alcohol and the sensor resistance began to decline. Simultaneously, breath alcohol measurements were attained using a DRAGER 6820 certified breathalyzer. The results demonstrated a clear correlation between the alcohol concentration in the blood, breath, and via perspiration, which validated the embedded transdermal alcohol device reported in this work.

scholarly journals Graphene and its Derivatives-Based Optical Sensors

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiao-Guang Gao ◽  
Ling-Xiao Cheng ◽  
Wen-Shuai Jiang ◽  
Xiao-Kuan Li ◽  
Fei Xing
Keyword(s):  
Optical Sensors ◽  
Low Cost ◽  
High Sensitivity ◽  
Fast Response ◽  
Cell Detection ◽  
Single Cell Detection ◽  
Sensing Applications ◽  
Wide Range ◽  
Surface Enhanced Raman ◽  
Recent Developments

Being the first successfully prepared two-dimensional material, graphene has attracted extensive attention from researchers due to its excellent properties and extremely wide range of applications. In particular, graphene and its derivatives have displayed several ideal properties, including broadband light absorption, ability to quench fluorescence, excellent biocompatibility, and strong polarization-dependent effects, thus emerging as one of the most popular platforms for optical sensors. Graphene and its derivatives-based optical sensors have numerous advantages, such as high sensitivity, low-cost, fast response time, and small dimensions. In this review, recent developments in graphene and its derivatives-based optical sensors are summarized, covering aspects related to fluorescence, graphene-based substrates for surface-enhanced Raman scattering (SERS), optical fiber biological sensors, and other kinds of graphene-based optical sensors. Various sensing applications, such as single-cell detection, cancer diagnosis, protein, and DNA sensing, are introduced and discussed systematically. Finally, a summary and roadmap of current and future trends are presented in order to provide a prospect for the development of graphene and its derivatives-based optical sensors.

Nanomaterial LaNiTiO3-Fe3O4-based peroxidase biomimetic sensor with high sensitivity

2020 ◽  
Vol 16 ◽  
Author(s):  
Yanhong Xu ◽  
Ying Sun ◽  
Qiao Feng
Keyword(s):  
Detection Limit ◽  
Low Cost ◽  
Supporting Electrolyte ◽  
High Sensitivity ◽  
Fast Response ◽  
H2o2 Concentration ◽  
Current Time ◽  
Real Samples ◽  
Wide Range ◽  
Biomimetic Sensor

Background: Hydrogen peroxide (H2O2) is widely present in various fields. And H2O2 plays quintessential role in variety of biomolecular processes. H2O2 concentration level is an essential biological parameter in monitoring and maintaining the physiological balance of a living cell, and its variation will cause some related diseases. Therefore, it is extremely significant to fabricate biosensor with low cost which can quickly, accurately and sensitively detect H2O2 in a wide range. The aims of this paper are to explore a novel electrochemical sensor with high intrinsic peroxidase-like activity, high sensitivity and stability to detect effectively H2O2 concentration in real samples. Methods: The chemical modified electrode LaNiTiO3-Fe3O4/GCE is fabricated based on nanomaterial LaNiTiO3-Fe3O4 by simply process, and its electrochemical properties are investigated in the supporting electrolyte of 0.1 M NaOH by the techniques of cyclic voltammetry and current-time curves on an electrochemical workstation with a conventional threeelectrode system. Results: LaNiTiO3-Fe3O4 nanoparticles show good peroxidase-like activity for H2O2 at a low applied potential of +0.50 V. Under the optimum conditions, the peroxidase biomimetic sensor LaNiTiO3-Fe3O4/GCE exhibits a wide linear response for H2O2 oxidation in the range of 0.05 μM - 3.0 mM (R = 0.9994) with a high sensitivity of 3946.2 μA∙mM1 ∙cm-2 and fast response time of 2 s, and the detection limit of H2O2 is found to be ca. 5.15 nM (S/N = 3). Moreover, the biosensor presents a good repeatability, stability and anti-interference. Satisfactory results were obtained when the sensor LaNiTiO3-Fe3O4/GCE is applied to determine H2O2 in real samples. All of these results provide support to practical application. Conclusion: A highly sensitive peroxidase biomimetic sensor based on LaNiTiO3-Fe3O4 with nano-scaled material is successfully explored, and shows good activity for H2O2. The proposed biosensor with simple and low cost has exhibited excellent advantages of quick response, wide linear range, low detection limit, high sensitivity, long-term stability and good anti-interference ability, which provides promising applications.

scholarly journals MWCNT Devices Fabricated by Dielectrophoresis: Study of Their Electrical Behavior Related to Deposited Nanotube Amount for Gas Sensing Applications

2015 ◽  
Vol 10 (1) ◽  
pp. 13-20
Author(s):  
Elisabete Galeazzo ◽  
Marcos C. Moraes ◽  
Henrique E. M. Peres ◽  
Michel O. S. Dantas ◽  
Victor G. C. Lobo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Cost Effective ◽  
Adsorbed Water ◽  
Fast Response ◽  
Process Time ◽  
Electrical Behavior ◽  
Glass Substrates ◽  
Sensing Applications

Intensive research has been focused on investigating new sensing materials, such as carbon nanotubes (CNT) because of their promising characteristics. However, there are challenges related to their application in commercial devices such as sensitivity, compatibility, and complexity of miniaturization, among others. We report the study of the electrical behavior of devices composed by multi-walled carbon nanotubes (MWCNT) deposited between aluminum electrodes on glass substrates by means of dielectrophoresis (DEP), which is a simple and cost-effective method. The devices were fabricated by varying the DEP process time. Remarkable changes in their electric resistance were noticed depending on the MWCNT quantities deposited. Other electrical properties of devices such as high sensitivity, fast response time and stability are also characterized in humid environment. A humidity sensing mechanism is proposed on the basis of charge transfer between adsorbed water molecules and the MWNTC surface or between water and the glass surface.

scholarly journals A Novel Type Room Temperature Surface Photovoltage Gas Sensor Device 

2018 ◽  
Author(s):  
Monika Kwoka ◽  
Michal A. Borysiewicz ◽  
Pawel Tomkiewicz ◽  
Anna Piotrowska ◽  
Jacek Szuber
Keyword(s):  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Fast Response ◽  
Surface Photovoltage ◽  
Kelvin Probe ◽  
Sensor Device ◽  
Developed Surface

In this paper a novel type of a highly sensitive gas sensor device based on the surface photovoltage effect is described. The developed surface photovoltage gas sensor is based on a reverse Kelvin probe approach. As the active gas sensing electrode the porous ZnO nanostructured thin films are used deposited by the direct current (DC) reactive magnetron sputtering method exhibiting the nanocoral surface morphology combined with an evident surface nonstoichiometry related to the unintentional surface carbon and water vapor contaminations. Among others, the demonstrated SPV gas sensor device exhibits a high sensitivity of 1 ppm to NO2 with a signal to noise ratio of about 50 and a fast response time of several seconds under the room temperature conditions.

A Dynamic Data Fragmentation and Distribution Strategy for Main-Memory Database Cluster

2012 ◽  
Vol 490-495 ◽  
pp. 1231-1236 ◽  
Author(s):  
Tran Van Hung ◽  
Chuan He Huang
Keyword(s):  
Response Time ◽  
Cluster Computing ◽  
Data Access ◽  
Fast Response ◽  
Main Memory ◽  
Relation Database ◽  
Computing Platform ◽  
Wide Range ◽  
Cluster Environment ◽  
Remote Sites

MMDB cluster system is a memory optimized relation database that implements on cluster computing platform, provides applications with extremely fast response time and very high throughput as required by many applications in a wide range of industries. Here, a new dynamic fragment allocation algorithm (DFAPR) in Partially Replicated allocation scenario is proposed. This algorithm reallocates data with respect to changing data access pattern for each fragment in which data is maintained in current site, migrated or created new replicas on remote sites depend on accessing frequency and average response time. At last, the simulation results show that the DFAPR is suitable for MMDB cluster because it provides a better response time and maximize the locality of processing so it could be developed parallel processing of MMDB in cluster environment.

scholarly journals A Review of Carbon Nanotubes-Based Gas Sensors

2009 ◽  
Vol 2009 ◽  
pp. 1-24 ◽  
Author(s):  
Yun Wang ◽  
John T. W. Yeow
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Low Cost ◽  
High Surface ◽  
Hollow Structure ◽  
Volume Ratio ◽  
Fast Response ◽  
Sensing Technology ◽  
Structure Of Nanomaterials

Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs) has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.

scholarly journals Soft and ion-conducting hydrogel artificial tongue for astringency perception

2020 ◽  
Vol 6 (23) ◽  
pp. eaba5785 ◽  
Author(s):  
Jeonghee Yeom ◽  
Ayoung Choe ◽  
Seongdong Lim ◽  
Youngsu Lee ◽  
Sangyun Na ◽  
...  
Keyword(s):  
Flexible Substrate ◽  
High Sensitivity ◽  
Humanoid Robots ◽  
Fast Response ◽  
Nanoporous Structure ◽  
Proof Of Concept ◽  
Human Tongue ◽  
Wide Range ◽  
Ion Conducting ◽  
Monitoring Devices

Artificial tongues have been receiving increasing attention for the perception of five basic tastes. However, it is still challenging to fully mimic human tongue–like performance for tastes such as astringency. Mimicking the mechanism of astringency perception on the human tongue, we use a saliva-like chemiresistive ionic hydrogel anchored to a flexible substrate as a soft artificial tongue. When exposed to astringent compounds, hydrophobic aggregates form inside the microporous network and transform it into a micro/nanoporous structure with enhanced ionic conductivity. This unique human tongue–like performance enables tannic acid to be detected over a wide range (0.0005 to 1 wt %) with high sensitivity (0.292 wt %−1) and fast response time (~10 s). As a proof of concept, our sensor can detect the degree of astringency in beverages and fruits using a simple wipe-and-detection method, making a powerful platform for future applications involving humanoid robots and taste monitoring devices.

A dual-responsive fluorescent sensor for Hg2+ and thiols based on N-doped silicon quantum dots and its application in cell imaging

2019 ◽  
Vol 7 (44) ◽  
pp. 7033-7041 ◽  
Author(s):  
Sansan Shen ◽  
Bohui Huang ◽  
Xiaofeng Guo ◽  
Hong Wang
Keyword(s):  
Quantum Dots ◽  
Response Time ◽  
Cell Imaging ◽  
Fluorescent Sensor ◽  
High Sensitivity ◽  
Fast Response ◽  
Silicon Quantum Dots ◽  
Fast Response Time ◽  
Dual Responsive ◽  
Doped Silicon

An on–off–on fluorescent sensor based on N-SiQD has the advantages of fast response time and high sensitivity to Hg2+ and GSH.

Effects of Preparing Conditions on NO2-Sensing Properties of Sputtered WO3 Nano-Films

2013 ◽  
Vol 690-693 ◽  
pp. 1680-1684
Author(s):  
Feng Yun Sun ◽  
Ming Hu ◽  
Peng Sun
Keyword(s):  
Gas Sensing ◽  
High Sensitivity ◽  
Fast Response ◽  
Optimal Parameters ◽  
Working Pressure ◽  
Sensing Properties ◽  
Dc Reactive Magnetron Sputtering ◽  
Experiment Method ◽  
Discharge Gas ◽  
Gas Ratio

WO3 nano-films were deposited on Al2O3 substrate by dc reactive magnetron sputtering method. The effects of preparing conditions, such as the discharge gas ratio (Ar:O2), working pressure, sputtering time and annealing temperature on microstructure, crystalline state and NO2-sensing properties of WO3 nano-films were investigated by orthogonal trial experiment method. The optimum technological conditions were determined by orthogonal test and extreme difference analysis. The crystallization, morphology and composition of WO3 thin film obtained at the optimal parameters were studied by XRD, SEM and XPS. The gas sensing mechanism was also studied. WO3 nano-film shows high sensitivity, fast response, good selectivity at the best operating temperature 200°C.

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