scholarly journals Fumed SiO2-H2SO4-PVA Gel Electrolyte CO Electrochemical Gas Sensor

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 109
Author(s):  
Yuhang Zhang ◽  
Dongliang Cheng ◽  
Zicheng Wu ◽  
Feihu Li ◽  
Fang Fang ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Water Retention ◽  
Gel Electrolyte ◽  
Co Concentration ◽  
Recovery Times ◽  
Response And Recovery ◽  
Co Sensor ◽  
Pva Gel ◽  
Fumed Sio2

The conventional CO electrochemical gas sensor uses aqueous H2SO4 solution as electrolyte, with inevitable problems, such as the drying and leakage of electrolyte. Thus, research on new alternative electrolytes is an attractive field in electrochemical gas sensors. In this paper, the application of a new fumed SiO2 gel electrolyte was studied in electrochemical gas sensors. The effects of fumed SiO2 and H2SO4 contents on the performance of the CO gas sensor were investigated. The results showed that the optimized composition of the SiO2 gel electrolyte was 4.8% SiO2, 38% H2SO4, and 0.005% polyvinyl alcohol (PVA). Compared with aqueous H2SO4, the gel electrolyte had better water retention ability. The signal current of the sensor was proportional to the CO concentration. The sensitivity to CO was 78.6 nA/ppm, and the response and recovery times were 31 and 38 s, respectively. The detection limit was 2 ppm. The linear range was from 2 to 500 ppm. The gel electrolyte CO sensor possesses equivalent performance to that with aqueous electrolyte.

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.

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.

Using Palladium Nanocubes on ZnO Nanostructures in Hydrogen Gas Sensor for Fast Response and Recovery Time

2021 ◽  
Vol 21 (4) ◽  
pp. 2495-2499
Author(s):  
Hoang Si Hong ◽  
Tran Vinh Hoang
Keyword(s):  
Gas Sensor ◽  
Recovery Time ◽  
Fast Response ◽  
Hydrogen Gas ◽  
Zno Nanostructures ◽  
Response Recovery ◽  
Sensor Structure ◽  
Recovery Times ◽  
Response And Recovery ◽  
Robust Sensing

We developed a novel sensor structure by synthesizing Pd nanocubes (NCs) decorated on ZnO nanostructures (NSs) applied to resistive-type H2 gas sensor with micro-length in sensing channel. The ZnO NSs were selectively grown between micro-size finger-like interdigital electrodes through microelectromechanical technology. The novel H2 sensor structure with the sensing channel was reduced to micro-size by this proposed method to obtain a sensor with fast response/recovery time. The as-prepared structure exhibited robust sensing performance with a response of 11% at optimal temperature of 150 °C, good linearity, and fast response/recovery time within 10 s. The speed of chemisorption through the diffusion pathway in Pd NCs combined with micro-length in sensing channel in sensor showed fast response and recovery times of 9 and 15 s, respectively, toward 10,000 ppm (1%) H2 at 150 °C. The result showed approximate linearity response in H2 concentration range of 5÷10,000 ppm and a large operating temperature range from room temperature to 200 °C.

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.

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.

Dual MOSFET Hydrogen Sensors with Thermal Island Structure

2013 ◽  
Vol 543 ◽  
pp. 93-96
Author(s):  
Bum Joon Kim ◽  
Jung Sik Kim
Keyword(s):  
Gas Sensor ◽  
Hydrogen Sensor ◽  
Hydrogen Gas ◽  
Hydrogen Sensors ◽  
Optimal Point ◽  
Reference Device ◽  
Recovery Times ◽  
Dual Gate ◽  
Response And Recovery ◽  
Effect Transistor

A low powered hydrogen gas sensor of the FET (field-effect transistor) structure was designed, fabricated and characterized for self-compensation to outer environments. The dual-gate FET hydrogen sensor was integrated with a micro-heater and two Pt-gate FETs; a sensing device for hydrogen detection, and a reference device as an electrical compensator. The identical output between the sensitive-FET and reference-FET was stable at temperatures ranging from room temperature to 250°C due to the same temperature dependence of the currentvoltage (IV) characteristics. The Pt-FET sensor showed stable responses to hydrogen at a range of operation temperatures. The optimal point in the micro-heater operation for 5,000 ppm H2 gas injection was approximately 150°C. The highest sensitivity was 0.112 mA, and the response and recovery times were 18 sec and 19 sec, respectively. The low-power MOSFET gas sensor was found to be suitable for applications in portable gas monitoring units and automobiles.

High Response and Selectivity Methanol Gas Sensor Using Molecular Imprinting Technique

2014 ◽  
Vol 809-810 ◽  
pp. 731-736
Author(s):  
Qin Zhu ◽  
Yu Min Zhang ◽  
Jin Zhang ◽  
Zhong Qi Zhu ◽  
Qing Ju Liu
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
High Response ◽  
Molar Ratio ◽  
Methanol Vapor ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Infrared Spectrometer

A new gas sensor with high response and selectivity was fabricated by using molecularly imprinted powders (MIPs) which provide special recognition sites to methanol. The MIPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and fourier transform infrared spectrometer (FT-IR), respectively. The gas sensing properties of MIPs to methanol were investigated. The experimental results indicate that the sensors based on the MIPs show excellent gas sensing properties to methanol vapor, and the properties of the sensor with x=6:10 (x= methyl acrylic acid: LaFeO3, molar ratio) are the best. At the optimal operating temperature of 130°C, the response of the sensor (x=6:10) to 1 ppm methanol is 21, and the response and recovery times are 57 s and 67 s, respectively.

scholarly journals A Room-Temperature CNT/Fe3O4 Based Passive Wireless Gas Sensor

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3542 ◽  
Author(s):  
Tao Guo ◽  
Tianhao Zhou ◽  
Qiulin Tan ◽  
Qianqian Guo ◽  
Fengxiang Lu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Fast Response ◽  
Sensing Material ◽  
Recovery Times ◽  
Response And Recovery ◽  
Good Repeatability

A carbon nanotube/Fe3O4 thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe3O4 as a gas sensing material is explained. The design and fabrication process of the sensor and the testing method are introduced. Experimental results reveal that the proposed carbon nanotube (CNT)/Fe3O4 based sensor performs well on sensing ammonia (NH3) at room temperature. The sensor exhibits not only an excellent response, good selectivity, and fast response and recovery times at room temperature, but is also characterized by good repeatability and low cost. The results for the wireless gas sensor’s performance for different NH3 gas concentrations are presented. The developed device is promising for the establishment of wireless gas sensors in harsh environments.

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.

Fabrication and Analysis of Energy Efficient Low-Cost Wireless Gas Sensor Based on ZnO Thin Films

2021 ◽  
Vol 21 (4) ◽  
pp. 2132-2138
Author(s):  
Dineshkumar Mani ◽  
Kavitha Ponnusamy ◽  
Ganesh Kumar Mani ◽  
Dhivya Ponnusamy ◽  
Kazuyoshi Tsuchiya
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Energy Efficient ◽  
Low Cost ◽  
Cost Effective ◽  
Wireless Sensor ◽  
Industrial Control ◽  
Effective System ◽  
Response And Recovery ◽  
Sensor Assembly

Industrialization can be greatly appreciated only by limiting the downside of the proposed technology. In this aeon, the recurrent monitoring of industries is statutory in detecting harmful gases and explosions for the global environment safety. Hence, employing specific gas sensors for detecting malicious gases benefits the welfare of the society. Thus, in this present work, we developed an energy efficient toxic gas sensor using ZnO thin film by seed layer assisted hydrothermal technique. The sensing mechanism of ZnO with the CO analyte was explained and the sensing parameters such as sensitivity, selectivity, response and recovery time were studied. Further, the developed energy efficient sensor was embedded with wireless sensor assembly for online monitoring which may be functional in developing portable, compact and cost-effective system for various real time industrial control applications.

Sign in / Sign up

Export Citation Format

Share Document