scholarly journals Synthesis of CuO by Electrospinning Method for Sensing of Hydrogen and Carbon Monoxide Gases

2021 ◽  
Vol 68 (4) ◽  
pp. 945-954
Author(s):  
Abdollah Fallah Shojaei ◽  
Parisa Fallah Komsari
Keyword(s):  
Carbon Monoxide ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Particle Morphology ◽  
Fast Response ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Electrospinning Method ◽  
Response And Recovery

The pure CuO nanofibers were synthesized via the electrospinning method successfully. The calcinated CuO nanofibers were investigated for sensing hydrogen and carbon monoxide gases. Structural properties of the synthesized calcinated nanofibers were studied using Fourier –transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX), and particle morphology by scanning electron microscopy (SEM). SEM images confirmed string-like structures, nanofibers. The sensor based on the calcinated CuO nanofibers exhibited excellent gas sensing performance at the low operating temperature of 175 °C and the fast response and recovery characteristics at a low concentration. Moreover, good stability, prominent reproducibility, and excellent selectivity are also observed based on the calcinated nanofibers. These results demonstrate the potential application of calcinated CuO nanofibers for sensing hydrogen (10–200 ppm) and carbon monoxide (400–700 ppm) gases.

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, Characterization, and Mechanistic Understanding of Pd-Decorated ZnO Nanowires for Ethanol Sensing

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao Deng ◽  
Shengbo Sang ◽  
Pengwei Li ◽  
Gang Li ◽  
Fanqin Gao ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Operating Temperature ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
X Ray ◽  
Recovery Times ◽  
Response And Recovery ◽  
New Perspective ◽  
Ethanol Sensing ◽  
Higher Sensitivity

ZnO nanowires (ZnO-NWs) and Pd-decorated ZnO nanowires (Pd-ZnO-NWs) were prepared by hydrothermal growth and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). When used for gas sensing, both types of nanowires showed a good selectivity to ethanol but a higher sensitivity and lower operating temperature were found with Pd-ZnO-NWs sensors comparing to those of ZnO-NWs sensor. When exposed to 200 ppm ethanol, our ZnO-NWs sensor showed a sensitivity of about 2.69 at 425°C whereas 1.3 at. % Pd-ZnO-NWs sensor provided a 57% more detection sensibility at 325°C. In addition, both response and recovery times of Pd-ZnO-NWs sensors were significantly reduced (9 s) comparing to the ZnO-NWs. Finally, Pd-ZnO-NWs sensor also showed a much lower detection limit of about 1 ppm. The sensing mechanism of Pd-ZnO-NWs sensors has also been clarified, thereby providing a new perspective for further improvement of the sensing performance of ethanol sensors.

Detection of accumulated continuously ethanol concentration by ZnO–SnO2 composite nanorods sensor

2021 ◽  
pp. 2150395
Author(s):  
Xiang-Bing Li ◽  
Da-Qian Mo ◽  
Xiao-Yan Niu ◽  
Qian-Qian Zhang ◽  
Shu-Yi Ma ◽  
...  
Keyword(s):  
Recovery Time ◽  
Ethanol Concentration ◽  
Physical Adsorption ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
X Ray ◽  
Atomic Force ◽  
Electrospinning Method ◽  
Response And Recovery ◽  
Composite Nanorods

ZnO–SnO2 composite nanorods with rough surfaces were synthesized via a coaxially nested needle electrospinning method. The morphology and nanostructure were characterized by scanning electron microscopy, atomic force microscope, EDS mapping, nitrogen physical adsorption, and X-ray diffraction. The synthesis mechanisms of ZnO–SnO2 nanorods were discussed, which combined the gas sensitivity advantages of different materials. ZnO–SnO2 nanorods sensor with good ethanol gas sensitivity achieved accurate measurement of continuous ethanol concentration. The sensor exhibited good selectivity to ethanol in the presence of formaldehyde, methanol, acetone, acetic acid, benzene, and xylene at 290[Formula: see text]C. The response and recovery time to 100 ppm ethanol were about 13 and 35 s, respectively. The energy band, barrier, charge transfer of ZnO–SnO2 composite material was discussed, and its optimization of gas sensitivity was analyzed in detail.

scholarly journals Highly sensitive and selective sensing of H2S gas using precipitation and impregnation-made CuO/SnO2 thick films

2021 ◽  
Author(s):  
Pimpan Leangtanom ◽  
Anurat Wisitsoraat ◽  
Kata Jaruwongrangsee ◽  
Narong Chanlek ◽  
Adisorn Tuantranont ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Fast Response ◽  
Potential Candidate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Content ◽  
Transmission Electron ◽  
Highly Sensitive

Abstract In this work, CuO-loaded tetragonal SnO2 nanoparticles (CuO/SnO2 NPs) were synthesized using precipitation/impregnation methods with varying Cu contents of 0–25 wt% and characterized for H2S detection. The material phase, morphology, chemical composition and specific surface area of NPs were evaluated using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller analysis. From gas-sensing data, the H2S responses of SnO2 NPs were greatly enhanced by CuO loading particularly at the optimal Cu content of 20 wt%. The 20 wt%CuO/SnO2 sensor showed an excellent response of 1.36⋅105 towards 10 ppm H2S and high H2S selectivity against H2, SO2, CH4 and C2H2 at a low optimum working temperature of 200°C. In addition, the sensor provided fast response and a low detection limit of less than 0.15 ppm. The CuO-SnO2 sensor could therefore be a potential candidate for H2S detection in environmental applications.

scholarly journals Sputtered SnO2/ZnO Heterostructures for Improved NO2 Gas Sensing Properties

Chemosensors ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 67 ◽  
Author(s):  
Bharat Sharma ◽  
Ashutosh Sharma ◽  
Monika Joshi ◽  
Jae-ha Myung
Keyword(s):  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Operating Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Response Recovery ◽  
No2 Gas Sensor ◽  
Highly Sensitive ◽  
Gas Sensing Properties ◽  
Gas Response

A highly sensitive and selective NO2 gas sensor dependent on SnO2/ZnO heterostructures was fabricated using a sputtering process. The SnO2/ZnO heterostructure thin film samples were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). Sensors fabricated with heterostructures attained higher gas response (S = 66.9) and quicker response-recovery (20 s, 45 s) characteristics at 100 °C operating temperature towards 100 ppm NO2 gas efficiently in comparison to sensors based on their mono-counterparts. The selectivity and stability of SnO2/ZnO heterostructures were studied. The more desirable sensing mechanism of SnO2/ZnO heterostructures towards NO2 was described in detail.

Method for synthesizing ZnO of different nanostructures by electrospinning and study of their gas sensing properties

2019 ◽  
Vol 33 (25) ◽  
pp. 1950297
Author(s):  
Xiang-Bing Li ◽  
Shu-Yi Ma ◽  
Fu-Rong Li ◽  
Yu-Xiang Zhao ◽  
Xiao-Bin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Component Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrospinning Method ◽  
Gas Sensing Properties ◽  
Zno Nanofibers ◽  
Scanning Electron

The properties of nanomaterials usually depend on their microstructures, the same material of different microstructures could be used for various applications. However, most devices could only synthesize a single microstructure, so it is meaningful that the different microstructures were synthesized by one method. In our study, electrospinning was applied to fabricate ZnO nanofibers and nanoparticles. In this approach, Zn(Ac)/PVP composite fibers of different component ratio were synthesized by electrospinning method which was subsequently calcined and formed ZnO nanofibers and nanoparticles. The microstructure, chemical composition and gas sensing were investigated with scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and WS-60A gas sensing measurement system. The synthesis mechanisms of ZnO nanofibers and nanoparticles were discussed in detail.

Alcohol Sensing Properties of SnO2/CNT Nanocomposites Synthesized by Microwave-Assisted Process

2016 ◽  
Vol 675-676 ◽  
pp. 85-88
Author(s):  
Nalita Sawangjit ◽  
Wicharn Techitdheera ◽  
Wisanu Pecharapa
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Structural Morphology ◽  
X Ray ◽  
Multi Wall Carbon Nanotubes ◽  
Microwave Assisted ◽  
Sensing Sensitivity ◽  
Scanning Electron

SnO2/CNT nanocomposites were synthesized via microwave-assisted process using SnCl4·5H2O as a starting precursor and UV-treated multi-wall carbon nanotubes (MWCNTs) as scaffolds. The concentration of SnCl4 was varied in the range of 0.01-0.05 M. Effect of precursor concentration on their physical properties and micro structural morphology were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD results indicate that the as-synthesized composites are the mixture of two separated phases including SnO2 and MWCNT. SEM images indicate that the surfaces of MWCNT are thoroughly covered with SnO2 nanoparticles. Comparative gas sensing result reveals that the prepared hybrid SnO2/MWCNT composites exhibit much higher sensing sensitivity and recovery property in detecting alcohol gas at room temperature than the bare SnO2.

Mo-W-O thin films for CO sensing

2000 ◽  
Vol 638 ◽  
Author(s):  
Elisabetta Comini ◽  
Matteo Ferroni ◽  
Vincenzo Guidi ◽  
Giuliano Martinelli ◽  
Michele Sacerdoti ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Weight Ratio ◽  
X Ray Diffraction ◽  
Composite Target ◽  
X Ray ◽  
Structural Characterisation ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery

AbstractThe Mo-W-O thin films were deposited by RF reactive sputtering from composite target of W and Mo (20:80 weight ratio). Structural characterisation was carried out by X-ray diffraction spectroscopy and the composition of the film was obtained by Rutherford backscattering analysis. The layers were investigated by volt-amperometric technique for electrical and gas-sensing properties. The films were capable of sensing CO. No effect of poisoning of the surface was recorded and recovery of the resistance was complete. A concentration of CO as low as 15 ppm produced a relative variation in the conductance of 390% with response and recovery times of about 2 minutes at a working temperature of 200°C.

scholarly journals On-chip ZnO nanofibers prepared by electrospinning method for NO2 gas detection

2018 ◽  
Vol 27 (4) ◽  
pp. 317 ◽  
Author(s):  
Van Hoang Nguyen ◽  
Van Dung Nguyen ◽  
Quang Dat Do ◽  
Thi Minh Nguyet Quan ◽  
Manh Hung Chu ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Hexagonal Wurtzite Structure ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
X Ray ◽  
Electrospinning Method ◽  
Resistance Modulation ◽  
Zno Nanofibers ◽  
On Chip ◽  
Gas Response

In the present study, on-chip ZnO nanofibers were fabricated by means of the electrospinning technique followed by a calcination process at 600 oC towards the gas sensor application. The morphology, composition, and crystalline structure of the as-spun and annealed ZnO nanofibers were investigated by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD), respectively. The findings show that spider-net like ZnO nanofibers with a diameter of 60 – 100 nm were successfully synthesized without any incorporation of impurities into the nanofibers. The FESEM images also reveal that each nanofiber is composed of many nanograins. The combination of experimental and calculated X-ray diffraction data indicate that ZnO nanofibers were crystallized in hexagonal wurtzite structure. For the gas sensing device application, the ZnO nanofibers-based sensors were tested with the nitrogen dioxide gas in the temperature range of 200 oC to 350 oC and concentrations from 2.5 ppm to 10 ppm. The sensing property results indicate that at the optimal working temperature of 300 oC, the ZnO nanofibers-based sensors exhibited a maximum response of 30 and 166 times on exposure of 2.5 and 10 ppm NO2 gas, respectively. The presence of nanograins within nanofibers, which results in further intensification of the resistance modulation, is responsible for such high gas response.

scholarly journals Effects of Niobium-Loading on Sulfur Dioxide Gas-Sensing Characteristics of Hydrothermally Prepared Tungsten Oxide Thick Film

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Viruntachar Kruefu ◽  
Anurat Wisitsoraat ◽  
Sukon Phanichphant
Keyword(s):  
Spin Coating ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Sensor Response ◽  
X Ray Diffraction ◽  
Optimal Operating ◽  
Impregnation Process ◽  
X Ray ◽  
Transmission Electron ◽  
Sensing Characteristics

Nb-loaded hexagonal WO3nanorods with 0–1.0 wt% loading levels were successfully synthesized by a simple hydrothermal and impregnation process and characterized for SO2sensing. Nb-loaded WO3sensing films were produced by spin coating on alumina substrate with interdigitated gold electrodes and annealed at 450°C for 3 h in air. Structural characterization by X-ray diffraction, high-resolution transmission electron microscopy, and Brunauer-Emmett-Teller analysis showed that spherical, oval, and rod-like Nb nanoparticles with 5–15 nm mean diameter were uniformly dispersed on hexagonal WO3nanorods with 50–250 nm diameter and 100 nm–5 µm length. It was found that the optimal Nb loading level of 0.5 wt% provides substantial enhancement of SO2response but the response became deteriorated at lower and higher loading levels. The 0.50 wt% Nb-loaded WO3nanorod sensing film exhibits the best SO2sensing performances with a high sensor response of ~10 and a short response time of ~6 seconds to 500 ppm of SO2at a relatively low optimal operating temperature of 250°C. Therefore, Nb loading is an effective mean to improve the SO2gas-sensing performances of hydrothermally prepared WO3nanorods.

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