Controlled electrochemical functionalization of MOx nanostructures by Au NPs for gas sensing application

2015 ◽  
Vol 1805 ◽  
Author(s):  
E. Dilonardo ◽  
M. Penza ◽  
M. Alvisi ◽  
C. Di Franco ◽  
F. Palmisano ◽  
...  

ABSTRACTStabilized Au NPs were directly deposited on nanostructured ZnO and ZrO2 by a simple one-step strategy based on sacrificial anode electrolysis. The annealed nanocomposites are proposed as active layers in resistive gas sensors for low-cost processes. Results on the performance of gas sensors based on pristine and Au-doped MOx nanostructured thin films, used for the detection of NO2 gas, were reported at an operating temperature of 300°C, evaluating the effects of the MOx chemical composition and morphology, and the Au-doping.

2015 ◽  
Vol 1786 ◽  
pp. 37-42 ◽  
Author(s):  
E. Dilonardo ◽  
M. Penza ◽  
M. Alvisi ◽  
C. Di Franco ◽  
D. Suriano ◽  
...  

ABSTRACTControlled amounts of colloidal Au nanoparticles (NPs), electrochemically pre-synthesized, were directly deposited on MWCNTs sensor devices by electrophoresis. Pristine and Au-functionalized MWCNT networked films were tested as active layers in resistive gas sensors for detection of pollutant gases. Au-modified CNT-chemiresistor demonstrated higher sensitivity to NO2 detecting up to sub-ppm level compared to pristine one. The investigation of the cross-sensitivity towards other pollutant gases revealed the decrease of the sensitivity to NO2 with the increase of Au content, and, on the other side, the increase of that to H2S; therefore the fine tune of the metal loading on CNTs has allowed to control not only the gas sensitivity but also the selectivity towards a specific gaseous analyte. Finally, the sensing properties of Au-decorated CNT sensor seem to be promising in environmental and automotive gas sensing applications, based on low power consumption and moderate operating temperature.


2020 ◽  
Vol 13 (06) ◽  
pp. 2051032
Author(s):  
Li Zhang ◽  
Chengwen Song ◽  
Xiaoxing Zhang ◽  
Zhemin Shi ◽  
Jingkun Xiao

Bi2MoxW[Formula: see text]O6 microspheres are synthesized by simple one-step hydrothermal method and the morphological characterizations are performed by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), BET, scanning electron microscopy (SEM), transmission electron microscopy (TEM). The gas sensing of Bi2WO6, Bi2MoO6 and Bi2MoxW[Formula: see text]O6 is investigated. It can be concluded that the sensor of Bi2MoxW[Formula: see text]O6 has the same good sensitivity as pure Bi2MoO6 and Bi2WO6 to alcohol. It is noteworthy that the operating temperature of Bi2Mo[Formula: see text]W[Formula: see text]O6 is 200∘C which is lower than that of pure Bi2WO6 or Bi2MoO6 (240∘C), so Bi2MoxW[Formula: see text]O6 show its good property for alcohol gas sensing application.


2017 ◽  
Vol 10 (03) ◽  
pp. 1750022 ◽  
Author(s):  
Mengying Xu ◽  
Zhidong Lin ◽  
Wenying Guo ◽  
Yuyuan Hong ◽  
Ping Fu ◽  
...  

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.


2020 ◽  
Vol 405 ◽  
pp. 324-329
Author(s):  
Erika Mudra ◽  
Ivan Shepa ◽  
Alexandra Kovalcikova ◽  
Ondrej Milkovič ◽  
Jan Dusza

SnO2 is an n-type semiconductor with the band gap energy of 3.6 eV. It has been widely studied for gas sensing applications, the sensitivity of which can be easily tuned by the operating temperature. The presented paper is focused on the preparation and detailed characterization of the hollow SnO2 nano/microfibers suitable for gas detection sensors. Ceramic SnO2 fibers were produced by needleless electrospinning and followed by the calcination process. The characterization was performed by SEM, TEM, XRD, and Raman spectroscopy. The precursor PVP/SnO2 fibers had amorphous nature. The calcination of the electro spun precursor resulted in the formation of hollow crystalline fibrous structures. The formation mechanism of hollow fibers has been described. Subsequently, a homogeneous fibrous layer was created by the spin coating method for gas sensing applications.


2009 ◽  
Vol 2009 ◽  
pp. 1-24 ◽  
Author(s):  
Yun Wang ◽  
John T. W. Yeow

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.


2017 ◽  
Vol 381 ◽  
pp. 15-19 ◽  
Author(s):  
Mukesh Chander Bhatnagar ◽  
Anima Johari

Tin oxide material has been extensively used for gas sensing application. Due to high operating temperature of metal oxide gas sensors, around 600 K and long term instability, research has been carried out to improve the material properties and reducing operating temperature. nanostructure materials have shown higher sensitivity and better stability towards gas environment. Air pollutants from automobiles and industry waste are the primary sources of environmental pollutants and there is need to develop low temperature, sensitive and selective gas sensors to monitor the gas content. In this paper, we have discussed the effect of Tungsten (W) doping in SnO2 nanostructures on the structural and gas sensing properties. The nanostructures have been synthesized by thermal evaporation process. The structural and surface morphology studies confirm the growth of nanowires on silicon substrates. The corresponding EDX spectra also confirm the doping of W into SnO2 nanowires. The gas sensor response of W-doped SnO2 nanowires was investigated upon exposure to various gases. It has been observed that doping of W enhances the NO2 sensitivity of nanowire based sensors at low temperature and the sensor response improves with increase in gas concentration.


RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 101304-101312 ◽  
Author(s):  
Xinxin Xing ◽  
Yuxiu Li ◽  
Dongyang Deng ◽  
Nan Chen ◽  
Xu Liu ◽  
...  

The aim of this paper is to develop easily manufactured and highly sensitive gas sensors for VOCs (volatile organic compounds) detection.


2020 ◽  
Vol 315 ◽  
pp. 128025 ◽  
Author(s):  
Mariana M.O. Netto ◽  
Wellington B. Gonçalves ◽  
Rosamaria W.C. Li ◽  
Jonas Gruber

2013 ◽  
Vol 201 ◽  
pp. 131-158 ◽  
Author(s):  
Ravi Chand Singh ◽  
Manmeet Pal Singh ◽  
Hardev Singh Virk

Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring, and process control. To meet this demand, considerable research into new sensors is underway, including efforts to enhance the performance of traditional devices, such as resistive metal oxide sensors, through nanoengineering. The resistance of semiconductors is affected by the gaseous ambient. The semiconducting metal oxides based gas sensors exploit this phenomenon. Physical chemistry of solid metal surfaces plays a dominant role in controlling the gas sensing characteristics. Metal oxide sensors have been utilized for several decades for low-cost detection of combustible and toxic gases. Recent advances in nanomaterials provide the opportunity to dramatically increase the response of these materials, as their performance is directly related to exposed surface volume. Proper control of grain size remains a key challenge for high sensor performance. Nanoparticles of SnO2have been synthesized through chemical route at 5, 25 and 50°C. The synthesized particles were sintered at 400, 600 and 800°C and their structural and morphological analysis was carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The reaction temperature is found to be playing a critical role in controlling nanostructure sizes as well as agglomeration. It has been observed that particle synthesized at 5 and 50°C are smaller and less agglomerated as compared to the particles prepared at 25°C. The studies revealed that particle size and agglomeration increases with increase in sintering temperature. Thick films gas sensors were fabricated using synthesized tin dioxide powder and sensing response of all the sensors to ethanol vapors was investigated at different temperatures and concentrations. The investigations revealed that sensing response of SnO2nanoparticles is size dependent and smaller particles display higher sensitivity. Table of Contents


2013 ◽  
Vol 431 ◽  
pp. 306-311
Author(s):  
Xiang Tao Ran ◽  
Zhi Wang ◽  
Li Yang

With the increasing needs for high-performance gas sensors in industrial production, environmental monitoring and so on, the research on gas sensors is becoming more and more important. In this paper, the electric field intensity distribution simulation process of the interdigital microelectrodes (IMEs) is discussed in details to get the proper electrode structural parameters. The IMEs on the ITO surface with a minimum gap of about 4μm are achieved by lithography, which provides a reliable, low-cost manufacturing method. Sensitive components are made of the multi-walled carbon nanotubes modified materials. The gas-sensing property of the sensor is detected for ammonia. The experiment result shows that the performance of the nanomodified sensor is obviously improved.


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