scholarly journals Fabrication of an acetone gas sensor based on Si doped WO3 nanorods prepared by reactive magnetron co-sputtering with OAD technique

Author(s):  
Waraporn Sucharitakul ◽  
Anupong Sukee ◽  
Pimchanok Leuasoongnoen ◽  
Mati Horprathum ◽  
Tossaporn Lertvanithphol ◽  
...  

Abstract Gas sensing technology is currently applied in a variety of applications. In medical applications, gas sensors can be used for the detection of the biomarker in various diseases, metabolic disorders, diabetes mellitus, asthma, renal, liver diseases, and lung cancer. In this study, we present acetone sensing characteristics of Si-doped WO3 nanorods prepared by a DC reactive magnetron co-sputtering with an oblique-angle deposition (OAD) technique. The composition of Si-doped in WO3 has been studied by varying the electrical input power applied to the Si sputtered target. The nanorods film was constructed at the glancing angle of 85°. After deposition, the films were annealed at 400 ◦C for 4 hrs in the air. The microstructures and phases of the materials were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM). The results showed that 1.43 wt% Si-doped WO3 thin film exhibited the maximum response of 5.92 towards 100 ppm of acetone at performing temperature (350 °C), purifying dry air carrier. The process exposed in this work demonstrated the potential of high sensitivity acetone gas sensor at low concentration and may be used as an effective tool for diabetes non-invasive monitoring.

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 445 ◽  
Author(s):  
Xiangfeng Guan ◽  
Yongjing Wang ◽  
Peihui Luo ◽  
Yunlong Yu ◽  
Dagui Chen ◽  
...  

The development of high-performance acetone gas sensor is of great significance for environmental protection and personal safety. SnO2 has been intensively applied in chemical sensing areas, because of its low cost, high mobility of electrons, and good chemical stability. Herein, we incorporated nitrogen atoms into the SnO2 nanostructure by simple solvothermal and subsequent calcination to improve gas sensing property for acetone. The crystallization, morphology, element composition, and microstructure of as-prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Electron paramagnetic resonance (EPR), Raman spectroscopy, UV–visible diffuse reflectance spectroscopy (UV–vis DRS), and the Brunauer–Emmett–Teller (BET) method. It has been found that N-incorporating resulted in decreased crystallite size, reduced band-gap width, increased surface oxygen vacancies, enlarged surface area, and narrowed pore size distribution. When evaluated as gas sensor, nitrogen-incorporated SnO2 nanostructure exhibited excellent sensitivity for acetone gas at the optimal operating temperature of 300 °C with high sensor response (Rair/Rgas − 1 = 357) and low limit of detection (7 ppb). The nitrogen-incorporated SnO2 gas sensor shows a good selectivity to acetone in the interfering gases of benzene, toluene, ethylbenzene, hydrogen, and methane. Furthermore, the possible gas-sensing mechanism of N-incorporated SnO2 toward acetone has been carefully discussed.


2020 ◽  
Vol 16 (2) ◽  
pp. 187-195
Author(s):  
Tang-Yu Lai ◽  
Te-Hua Fang ◽  
Yu-Jen Hsiao ◽  
En-Yu Kuo

Background:: A sensing material of zinc oxide (ZnO) was investigated for its use in the electrospun nanofibers for gas sensing. The metal oxide semiconductor gas sensor response is caused by the oxygen that undergoes a chemical reaction on the surface of an oxide, resulting in a change in the measured resistance. Objective:: One-dimensional nanofibers gas sensor have high sensitivity and diverse selectivity. Methods:: One-dimensional nanofiber by an electrospinning method was collected and a sensing membrane was formed. In addition, the gas sensing mechanism was discussed and verified by X-ray photoelectron spectroscopy (XPS). Results:: The ZnO nanofiber membrane had an optimum crystalline phase with a lattice spacing of 0.245 nm and a non-woven fabric structure at a calcination temperature of 500°C, whereas the nanofiber diameter and membrane thickness were about 100 nm and 8 μm, respectively. At an operating temperature of 200°C, the sensing material exhibited good recovery and reproducibility in response to Carbon monoxide (CO), and the concentration was also highly discernible. In addition, the reduction in the peak of OIII at 531.5 to 532.5 eV according to the analysis of XPS was consistent with the description of the sensing mechanism. Conclusion:: The gas sensor of ZnO nanofiber membranes has high sensitivity and diverse selectivity, which can be widely applied in potential applications in various sensors and devices.


2012 ◽  
Vol 1449 ◽  
Author(s):  
Chien-Tsung Wang ◽  
Huan-Yu Chen ◽  
Yu-Chung Chen

ABSTRACTGold species on an oxide support possess variable electronic structures via charge transition so as to increase their chemical redox activity. They are also viably promising for use to enhance gas-sensing response when being exploited in a solid state gas sensor. The synthesis method of the gold-loaded materials plays a crucial role in the functionality. In this paper, we report two types of gold/tin oxide based nanopowders prepared by co-precipitation method and by deposition-precipitation method, respectively. They were evaluated as sensing elements in a semiconductor carbon monoxide (CO) gas sensor. Effects of the material type and CO concentration on sensor response were investigated. Their structural characterizations were done by X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. Results demonstrate the surface gold species effective to facilitate CO oxidation in gas atmosphere and promote low-temperature sensor performance.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexander Ulyanov ◽  
Dmitrii Stolbov ◽  
Serguei Savilov

Abstract Jellyfish-like graphene nanoflakes (GNF), prepared by hydrocarbon pyrolysis, are studied with electron paramagnetic resonance (EPR) method. The results are supported by X-ray photoelectron spectroscopy (XPS) data. Oxidized (GNFox) and N-doped oxidized (N-GNFox) flakes exhibit an extremely high EPR response associated with a large interlayer interaction which is caused by the structure of nanoflakes and layer edges reached by oxygen. The GNFox and N-GNFox provide the localized and mobile paramagnetic centers which are silent in the pristine (GNF p ) and N-doped (N-GNF) samples. The change in the relative intensity of the line corresponding to delocalized electrons is parallel with the number of radicals in the quaternary N-group. The environment of localized and mobile electrons is different. The results can be important in GNF synthesis and for explanation of their features in applications, especially, in devices with high sensitivity to weak electromagnetic field.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 522
Author(s):  
Zhi Yan Lee ◽  
Huzein Fahmi bin Hawari ◽  
Gunawan Witjaksono bin Djaswadi ◽  
Kamarulzaman Kamarudin

A tin oxide (SnO2) and reduced graphene oxide (rGO) hybrid composite gas sensor for high-performance carbon dioxide (CO2) gas detection at room temperature was studied. Since it can be used independently from a heater, it emerges as a promising candidate for reducing the complexity of device circuitry, packaging size, and fabrication cost; furthermore, it favors integration into portable devices with a low energy density battery. In this study, SnO2-rGO was prepared via an in-situ chemical reduction route. Dedicated material characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were conducted. The gas sensor based on the synthesized hybrid composite was successfully tested over a wide range of carbon dioxide concentrations where it exhibited excellent response magnitudes, good linearity, and low detection limit. The synergistic effect can explain the obtained hybrid gas sensor’s prominent sensing properties between SnO2 and rGO that provide excellent charge transport capability and an abundance of sensing sites.


2020 ◽  
Author(s):  
M Abdul Kaiyum ◽  
Naim Ahmed ◽  
Arif Alam ◽  
M Shamimur Rahman

Abstract Yttrium (Y) doped and pure Titanium Di-oxide (TiO2) thin films were prepared by using spin coater. The coater was set up in laboratory with low cost investment. The films were calcined at 450 °C for 1 hour. For characterization, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) were carried out. LCR Bridge - GW Instek LCR-821 was used for gas sensing applications. XPS showed that the change of electronic structure due to Y doping. SEM and AFM analysis were carried out to determine the surface morphology of the films. Yttrium (Y) decreased the crystallite size of the films and increased the surface roughness and porosity value, which was very good for many sensing applications. Gas sensing property of the deposited films were improved by the incorporation of yttrium impurities and the sensing property improved almost two times than pure TiO2 thin film. Different researches have been done their research related to this topic but no one researchers provide a precise explanation of their results, authors of this research have tried to do that. Moreover the films were prepared by a simple spin coater to reduce the production cost also.


Author(s):  
S. Kumar ◽  
P. Gowthaman ◽  
J. Deenathayalan

Electro spinning technology combined with chemical precipitation method and high-temperature calcination was used to prepare SnO2-NiO composite semiconductor nanofibers with different Sn content. Scanning electron microscope (SEM), X-ray diffractometer (XRD) and energy dispersive X-ray spectrometer (EDS) were used to characterize the morphology, structure and content of various elements of the sample. Using ethanol as the target gas, the gas sensing properties of SnO2-NiO nanofibers and the influence of Sn content on the gas sensing properties of composite nanofibers were explored. The research results show that SnO2-NiO composite nanofibers have a three-dimensional network structure, and the SnO2 composite can significantly enhance the gas sensitivity of NiO nanofibers. With increase of SnO2 content, the response sensitivity of composite fibers to ethanol gas increases, and the response sensitivity of composite nanofibers with the highest response to ethanol gas with a volume fraction of 100×10-6 at the optimal working temperature of 160℃ are13.4;It is 8.38 times the maximum response sensitivity of NiO nanofibers. Compared with the common ethanol gas sensor MQ-3 on the market, SnO2-NiO composite nanofibers have a lower optimal working temperature and higher response sensitivity, which has certain practical application value


Author(s):  
Monika Kwoka ◽  
Michal A. Borysiewicz ◽  
Pawel Tomkiewicz ◽  
Anna Piotrowska ◽  
Jacek Szuber

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.


2021 ◽  
Vol 16 (3) ◽  
pp. 363-367
Author(s):  
Gaoqi Zhang ◽  
Fan Zhang ◽  
Kaifang Wang ◽  
Tao Tian ◽  
Shanyu Liu ◽  
...  

Accurate and real-time detection of formaldehyde (HCHO) in indoor air is urgently needed for human health. In this work, a ceramic material (WO3·H2O) with unique structure was successfully prepared using an efficient hydrothermal method. The crystallinity, morphology and microstructure of the as-prepared sensing material were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) as well as transmission electron microscope (TEM). The characterization results suggest that the as-prepared sample is composed of square-like nanoplates with uneven surface. Formaldehyde vapor is utilized as the target gas to investigate gas sensing properties of the synthesized novel nanoplates. The testing results indicate that the as-fabricated gas sensor exhibit high gas response and excellent repeatability to HCHO gas. The response value (Ra/Rg) is 24.5 towards 70 ppm HCHO gas at 350 °C. Besides, the gas sensing mechanism was described.


Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4340
Author(s):  
Han-Wei Chang ◽  
Chia-Wei Su ◽  
Jia-Hao Tian ◽  
Yu-Chen Tsai

Zn-Co-S ball-in-ball hollow sphere (BHS) was successfully prepared by solvothermal sulfurization method. An efficient strategy to synthesize Zn-Co-S BHS consisted of multilevel structures by controlling the ionic exchange reaction was applied to obtain great performance electrode material. Carbon nanotubes (CNTs) as a conductive agent were uniformly introduced with Zn-Co-S BHS to form Zn-Co-S BHS/CNTs and expedited the considerable electrocatalytic behavior toward glucose electro-oxidation in alkaline medium. In this study, characterization with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) was used for investigating the morphological and physical/chemical properties and further evaluating the feasibility of Zn-Co-S BHS/CNTs in non-enzymatic glucose sensing. Electrochemical methods (cyclic voltammetry (CV) and chronoamperometry (CA)) were performed to investigate the glucose sensing performance of Zn-Co-S BHS/CNTs. The synergistic effect of Faradaic redox couple species of Zn-Co-S BHS and unique conductive network of CNTs exhibited excellent electrochemical catalytic ability towards the glucose electro-oxidation, which revealed linear range from 5 to 100 μM with high sensitivity of 2734.4 μA mM−1 cm−2, excellent detection limit of 2.98 μM, and great selectivity in the presence of dopamine, uric acid, ascorbic acid, and fructose. Thus, Zn-Co-S BHS/CNTs would be expected to be a promising material for non-enzymatic glucose sensing.


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