scholarly journals (Ti,Sn) Solid Solution Based Gas Sensors for New Monitoring of Hydraulic Oil Degradation

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 605
Author(s):  
Ambra Fioravanti ◽  
Pietro Marani ◽  
Giorgio Paolo Massarotti ◽  
Stefano Lettieri ◽  
Sara Morandi ◽  
...  
Keyword(s):  
Solid Solution ◽  
Gas Sensors ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
Innovative Methodology ◽  
Recovery Times ◽  
Response And Recovery ◽  
Vapor Analysis ◽  
Screen Printing Technology ◽  
Proper Operation

The proper operation of a fluid power system in terms of efficiency and reliability is directly related to the fluid state; therefore, the monitoring of fluid ageing in real time is fundamental to prevent machine failures. For this aim, an innovative methodology based on fluid vapor analysis through metal oxide (shortened: MOX) gas sensors has been developed. Two apparatuses were designed and realized: (i) a dedicated test bench to fast-age the fluid under controlled conditions; (ii) a laboratory MOX sensor system to test the headspace of the aged fluid samples. To prepare the set of MOX gas sensors suitable to detect the analytes’ concentrations in the fluid headspace, different functional materials were synthesized in the form of nanopowders, characterizing them by electron microscopy and X-ray diffraction. The powders were deposited through screen-printing technology, realizing thick-film gas sensors on which dynamical responses in the presence of the fluid headspace were obtained. It resulted that gas sensors based on solid solution TixSn1–xO2 with x = 0.9 and 0.5 offered the best responses toward the fluid headspace with lower response and recovery times. Furthermore, a decrease in the responses (for all sensors) with fluid ageing was observed.

Acetylene Sensing by ZnO/TiO2 Nanoparticles

2020 ◽  
Vol 15 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Zhi-Cheng Zhong ◽  
Zhao-Jun Jing ◽  
Kui-Yuan Liu ◽  
Tong Liu
Keyword(s):  
Gas Sensors ◽  
Operating Temperature ◽  
Sol Gel ◽  
Fast Response ◽  
X Ray Diffraction ◽  
Uniform Size ◽  
X Ray ◽  
Recovery Times ◽  
Response And Recovery ◽  
Hydrothermal Methods

We adopted the sol–gel and hydrothermal methods to prepare the TiO2 nanomaterials doped with ZnO. We adopted X-ray diffraction, scanning electron microscopy, and the Brunauer–Emmett–Teller method to investigate the materials’ structures and morphologies. The results showed that the prepared TiO2 nanomaterials had uniform size and good dispersibility. Gas sensors were fabricated and their performances in acetylene sensing were assessed. The results show that the sensor prepared with the ZnO/TiO2 nanomaterial doped with 10 wt% ZnO gave fast response and recovery times for acetylene gas at different concentrations. When the operating temperature was 280 °C, the gas sensor detected 200 ppm acetylene gas with a response sensitivity of 9.9, a response time of 5 s, and a recovery time of 2 s.

scholarly journals Preparation of Powders Containing Sb, Ni, and O for the Design of a Novel CO and C3H8 Sensor

2021 ◽  
Vol 11 (20) ◽  
pp. 9536
Author(s):  
Jorge Alberto Ramírez-Ortega ◽  
José Trinidad Guillén-Bonilla ◽  
Alex Guillén-Bonilla ◽  
Verónica María Rodríguez-Betancourtt ◽  
Lorenzo Gildo-Ortiz ◽  
...  
Keyword(s):  
Response Times ◽  
High Capacity ◽  
Dynamic Tests ◽  
X Ray Diffraction ◽  
Wet Chemistry ◽  
Good Thermal Stability ◽  
Great Performance ◽  
Vis Spectroscopy ◽  
Recovery Times ◽  
Response And Recovery

In this work, powders of NiSb2O6 were synthesized using a simple and economical microwave-assisted wet chemistry method, and calcined at 700, 800, and 900 °C. It was identified through X-ray diffraction that the oxide is a nanomaterial with a trirutile-type structure and space group P42/mnm (136). UV–Vis spectroscopy measurements showed that the bandgap values were at ~3.10, ~3.14, and ~3.23 eV at 700, 800, and 900 °C, respectively. Using scanning electron microscopy (SEM), irregularly shaped polyhedral microstructures with a size of ~154.78 nm were observed on the entire material’s surface. The particle size was estimated to average ~92.30 nm at the calcination temperature of 900 °C. Sensing tests in static atmospheres containing 300 ppm of CO at 300 °C showed a maximum sensitivity of ~72.67. On the other hand, in dynamic atmospheres at different CO flows and at an operating temperature of 200 °C, changes with time in electrical resistance were recorded, showing a high response, stability, and repeatability, and good sensor efficiency during several operation cycles. The response times were ~2.77 and ~2.10 min to 150 and 200 cm3/min of CO, respectively. Dynamic tests in propane (C3H8) atmospheres revealed that the material improved its response in alternating current signals at two different frequencies (0.1 and 1 kHz). It was also observed that at 360 °C, the ability to detect propane flows increased considerably. As in the case of CO, NiSb2O6’s response in propane atmospheres showed very good thermal stability, efficiency, a high capacity to detect C3H8, and short response and recovery times at both frequencies. Considering the great performance in propane flows, a sensor prototype was developed that modulates the electrical signals at 360 °C, verifying the excellent functionality of NiSb2O6.

Xylene-sensing of Fe2(MoO4)3 nanoplates prepared via a hydrothermal method

2017 ◽  
Vol 10 (03) ◽  
pp. 1750022 ◽  
Author(s):  
Mengying Xu ◽  
Zhidong Lin ◽  
Wenying Guo ◽  
Yuyuan Hong ◽  
Ping Fu ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Hydrothermal Process ◽  
Optimum Operating ◽  
Average Crystalline Size ◽  
Optimum Operating Temperature ◽  
Recovery Times ◽  
Response And Recovery ◽  
Simple Hydrothermal Process

Fe2(MoO4)3 nanoplates were prepared via a simple hydrothermal process. The average crystalline size of these nanoplates is 85.8[Formula: see text]nm. The sensor based on Fe2(MoO4)3 shows a high gas sensing performance to xylene. The response of Fe2(MoO4)3 sensor is 25.9–100[Formula: see text]ppm xylene at optimum operating temperature of 340[Formula: see text]C. The response and recovery times to 100[Formula: see text]ppm xylene are 4 and 10[Formula: see text]s, respectively. Furthermore, the Fe2(MoO4)3 sensor exhibits remarkable selectivity detection of xylene gas with negligible responses to toluene and benzene. Therefore, the Fe2(MoO4)3 is a promising material for the detection of xylene gas sensors.

Fabrication of TiO2 sensor using rapid breakdown anodization method to measure pressure, humidity and sense gases at room temperature

2019 ◽  
pp. 1694-1703
Author(s):  
Reem Saadi Khaleel ◽  
Mustafa Shakir Hashim
Keyword(s):  
Room Temperature ◽  
Average Pressure ◽  
Spherical Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recovery Times ◽  
Sensitivity And Selectivity ◽  
Response And Recovery ◽  
Anodization Method ◽  
Rapid Breakdown Anodization

Rapid breakdown anodization (RBA) process was used to fabricate TiO2 sensor to measure pressure and humidity and sense gases at room temperature. This chemical process transformed Ti to its oxide (TiO2) as a powder with amorphous phase as X ray diffraction (XRD) technique confirmed.  This oxide consisted from semi spherical nanoparticles and titania nanotubes (TNTs) as Scanning electron microscope (SEM) technique showed.  TiO2 powder was deposited on Ti substrates by using electrophoretic deposition (EPD) method.   Average pressure sensitivity was 0.34 MΩ/bar and hysteresis area was 1.4 MΩ .bar. Resistance of TiO2 decreased exponentially with the increasing of relative humidity (RH%). The sensitivity% of TiO2 for RH% was greater than 70% in the range of (50-95). TiO2 was tested as a sensor for Ammonia, Ethanol and Methanol. Its sensitivity and selectivity towards Ammonia were the greatest but the shortest response and recovery times were recorded toward Methanol.

scholarly journals Nanostructured SmFeO3 Gas Sensors: Investigation of the Gas Sensing Performance Reproducibility for Colorectal Cancer Screening

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5910
Author(s):  
Andrea Gaiardo ◽  
Giulia Zonta ◽  
Sandro Gherardi ◽  
Cesare Malagù ◽  
Barbara Fabbri ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Gas Sensors ◽  
Process Development ◽  
Gas Sensing ◽  
Diagnostic Tools ◽  
Fecal Samples ◽  
Recovery Times ◽  
Medical Diagnostic ◽  
Response And Recovery ◽  
Sensing Performance

Among the various chemoresistive gas sensing properties studied so far, the sensing response reproducibility, i.e., the capability to reproduce a device with the same sensing performance, has been poorly investigated. However, the reproducibility of the gas sensing performance is of fundamental importance for the employment of these devices in on-field applications, and to demonstrate the reliability of the process development. This sensor property became crucial for the preparation of medical diagnostic tools, in which the use of specific chemoresistive gas sensors along with a dedicated algorithm can be used for screening diseases. In this work, the reproducibility of SmFeO3 perovskite-based gas sensors has been investigated. A set of four SmFeO3 devices, obtained from the same screen-printing deposition, have been tested in laboratory with both controlled concentrations of CO and biological fecal samples. The fecal samples tested were employed in the clinical validation protocol of a prototype for non-invasive colorectal cancer prescreening. Sensors showed a high reproducibility degree, with an error lower than 2% of the response value for the test with CO and lower than 6% for fecal samples. Finally, the reproducibility of the SmFeO3 sensor response and recovery times for fecal samples was also evaluated.

scholarly journals UV Sensitivity of Indium-Zinc Oxide Nanofibers

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Nadezhda Markova ◽  
Olga Berezina ◽  
Nikolay Avdeev ◽  
Alexander Pergament
Keyword(s):  
Zinc Oxide ◽  
Indium Content ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Indium Zinc Oxide ◽  
Electrospinning Method ◽  
Recovery Times ◽  
Response And Recovery

Indium-zinc oxide (IZO) nanofiber matrices are synthesized on SiO2-covered silicon substrates by the electrospinning method. The nanofibers’ dimensions, morphology, and crystalline structure are characterized by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The results of studying the electrical properties of nanofibers, as well as their sensitivity to UV radiation depending on the In-to-Zn concentration ratio, are presented. It is shown that the highest sensitivity to UV is observed at the indium content of about 50 atomic %. The photocurrent increment with respect to the dark current is more than 4 orders of magnitude. The response and recovery times are 60 and 500 sec, respectively. The results obtained suggest that IZO nanofibers can find application as UV sensors with improved characteristics.

A Formaldehyde Gas Sensor Based on Zinc Doped Lanthanum Ferrite

2013 ◽  
Vol 873 ◽  
pp. 304-310 ◽  
Author(s):  
Jin Zhang ◽  
Yu Min Zhang ◽  
Chang Yi Hu ◽  
Zhong Qi Zhu ◽  
Qing Ju Liu
Keyword(s):  
Gas Sensing ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Lanthanum Ferrite ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Sensing Characteristics

The gas-sensing properties of zinc doped lanthanum ferrite (Zn-LaFeO3) compounds for formaldehyde were investigated in this paper. Zn-LaFeO3 powders were prepared using sol-gel method combined with microwave chemical synthesis. The powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formaldehyde gas-sensing characteristics for the sample were examined. The experimental results indicate that the sensor based on the sample Zn-LaFeO3 shows excellent gas-sensing properties to formaldehyde gas. At the optimal operating temperature of 250°C, the sensitivity of the sensor based on LaFe0.7Zn0.3O3 to 100ppm formaldehyde is 38, while to other test gases, the sensitivity is all lower than 20. The response and recovery times for the sample to formaldehyde gas are 100s and 100s, respectively.

scholarly journals Synthesis of ZnO-CuO flower-like hetero-nanostructures as volatile organic compounds (VOCs) sensor at room temperature

2018 ◽  
Vol 36 (3) ◽  
pp. 452-459
Author(s):  
Raad S. Sabry ◽  
Roonak Abdul Salam A. Alkareem
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Room Temperature ◽  
Dip Coating ◽  
X Ray Diffraction ◽  
X Ray ◽  
Volatile Organic ◽  
Recovery Times ◽  
Coating Methods ◽  
Response And Recovery

AbstractZnO-CuO flower-like hetero-nanostructures were successfully prepared by combining hydrothermal and dip coating methods. Flower-like hetero-nanostructures of ZnO-CuO were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV-Vis. The sensing properties of ZnO-CuO flower-like hetero-nanostructures to volatile organic compounds (VOCs) were evaluated in a chamber containing acetone or isopropanol gas at room temperature. The sensitivity of ZnO-CuO flower-like hetero-nanostructures to VOCs was enhanced compared to that of pure leafage-like ZnO nanostructures. Response and recovery times were about 5 s and 6 s to 50 ppm acetone, and 10 s and 8 s to 50 ppm isopropanol, respectively. The sensing performance of ZnO-CuO flower-like hetero-nanostructures was attributed to the addition of CuO that led to formation of p-n junctions at the interface between the CuO and ZnO. In addition, the sensing mechanism was briefly discussed.

Enhanced Gas Sensing of Tin Dioxide Based Sensor for Indoor Formaldehyde Application

2021 ◽  
Vol 16 (2) ◽  
pp. 337-342
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Shanyu Liu ◽  
Ying Wang ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Fast Response ◽  
Sensing Material ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Formaldehyde Sensing ◽  
Gas Response

Indoor formaldehyde detection is of great important at present. Using efficient solvothermal method, nanosheet-constructed and nanorod-constructed hierarchical tin dioxide (SnO2) microspheres were successfully synthesized in this work and used for the gas sensing material for indoor formaldehyde application. The as-prepared two kinds of SnO2 gas sensing materials were applied to fabricate the gas sensors and formaldehyde gas sensing experiments were carried out. The HCHO gas sensing tests indicate that the gas response of the nanosheet-constructed SnO2 microspheres is about 1.7 times higher than that of the nanorod-constructed SnO2 microspheres. In addition, both of the two SnO2 based gas sensors show almost fast response and recovery time to HCHO gas. For the nanosheet-constructed microspheres, the response value is estimated to be 32.0 at 350 °C to 60 ppm formaldehyde gas, while the response and recovery times are 7 and 5 s, respectively. The simple and efficient preparation method and improved gas sensing properties show that the as-synthesized hierarchical SnO2 microsphere that is constructed by a large amount of nanosheets exhibits significant potential application for the indoor formaldehyde sensing.

Nanostructured (Sn,Ti, Nb)O2 Solid Solution for Hydrogen Sensing

2006 ◽  
Vol 915 ◽  
Author(s):  
Maria Cristina Carotta ◽  
Michele Benetti ◽  
Vincenzo Guidi ◽  
Sandro Gherardi ◽  
Cesare Malagu' ◽  
...  
Keyword(s):  
Solid Solution ◽  
Screen Printing ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Hydrogen Sensing ◽  
The Mean ◽  
Co Precipitation ◽  
Screen Printing Technology ◽  
Reducing Gases

AbstractA novel co-precipitation route for preparing pure nanograined (Ti, Sn, Nb)O2 solid solution has been accomplished. The solid solution containing the three elements has been synthesized with the molar ratios for Sn:Ti:Nb 100:42:5. Electron microscopy and X-ray diffraction have been adopted to observe the morphology, the crystalline structure and the mean grain radius. Calcining at 550, 650, 850 or 1050 °C for 2h, showed rutile-like single-phase.The prepared powders have been deposited to produce gas sensors in form of thick films through screen-printing technology. SEM micrographs of both powders and films showed regularly-shaped particles with grain dimensions at nanometric level, the nanostructure being maintained up to 1050°C. The sensors have been tested with different reducing gases showing large responses to hydrogen and good selectivity.

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