Journal ArticleDOI
Hydrogen sensing characteristics of WO3 thin film conductometric sensors activated by Pt and Au catalysts
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In this paper, the effect of temperature dependence on response magnitude and the influence of the metal activator layers for hydrogen gas sensitivity are presented and discussed, and the effects of different operating temperatures on the sensitivity of the devices were studied in the range of 30-300 ÂC.Abstract:
The hydrogen gas sensing performance of platinum (Pt) and gold (Au) catalyst activated WO 3 thin films were investigated. The WO 3 thin films were deposited onto alumina transducers with platinum inter-digital electrodes using a R.F. magnetron sputtering. Exposure to hydrogen gas, results in changes in the carrier concentration and hence, the conductivity of the film. The sensors were found to exhibit excellent sensitivities towards different hydrogen concentrations of 0.125, 0.25, 0.50 and 1% in air. The effects of different operating temperatures on the sensitivity of the devices were studied in the range of 30–300 °C. It was observed that the Pt–WO 3 and Au–WO 3 sensors were approximately 161 and 40 times more sensitive than the non-activated WO 3 sensor, respectively. In this paper, the effect of temperature dependence on response magnitude and the influence of the metal activator layers for hydrogen gas sensitivity are presented and discussed.read more
Citations
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Journal ArticleDOI
Hydrogen Sensors - A review
TL;DR: There are an immense number of sensors reported in the literature for hydrogen detection and in this article these sensors are classified into eight different operating principles, such as measuring range, sensitivity, selectivity and response time.
Journal ArticleDOI
Nanostructured Tungsten Oxide – Properties, Synthesis, and Applications
Haidong Zheng,Jian Zhen Ou,Michael S. Strano,Richard B. Kaner,Arnan Mitchell,Kourosh Kalantar-zadeh +5 more
TL;DR: A general review of nanostructured Tungsten oxides, their properties, methods of synthesis, and a description of how they can be used in unique ways for different applications can be found in this article.
Journal ArticleDOI
Au-doped WO3-based sensor for NO2 detection at low operating temperature
Huijuan Xia,Yan Wang,Fanhong Kong,Shurong Wang,Baolin Zhu,Xianzhi Guo,Jun Zhang,Yanmei Wang,Shihua Wu +8 more
TL;DR: In this paper, pure and Au-doped WO3 powders for NO2 gas detection were prepared by a colloidal chemical method, and characterized via X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Xray photoelectron spectroscopy (XPS).
Journal ArticleDOI
Highly sensitive and selective hydrogen sulfide and toluene sensors using Pd functionalized WO3 nanofibers for potential diagnosis of halitosis and lung cancer
TL;DR: In this paper, Pd catalysts were used inside and/or outside of WO 3 nanofibers to improve toluene response and superior cross-sensitivity against H 2 S molecules.
Journal ArticleDOI
Hierarchical nanostructured WO3-SnO2 for selective sensing of volatile organic compounds.
TL;DR: A mixed metal oxide WO3-SnO2 nanostructured material synthesized in situ by a simple, single-step, one-pot hydrothermal method at 200 °C in 12 h is reported to demonstrate its superior sensing behavior towards volatile organic compounds (VOCs) such as ammonia, ethanol and acetone.
References
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Journal ArticleDOI
Nox gas sensing characteristics of wo3 thin films activated by noble metals (pd, pt, au) layers
TL;DR: In this paper, a WO3-based gas sensor has been fabricated by reactive reactive rf sputtering on glass substrates, where Palladium (Pd), platinum (Pt), gold (Au), noble metals (100-600 A), and Al layers (1500 A) were sputtered on top of them as upper electrodes for sensor output.
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Tungsten Oxide-Based Semiconductor Sensor Highly Sensitive to NO and NO2
TL;DR: In this article, a sintered sensor element based on WO3 was found to be very sensitive to NO and NO2 at 300 °C. The sensitivity, defined as the ratio of the resistance in the gases to that in air, was as high as 31 and 97 to 200 ppm NO and 80 ppm NO2.
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WO3 sputtered thin films for NOx monitoring
TL;DR: In this article, preliminary results concerning the preparation of tungsten trioxide thin films by reactive sputtering, the characterization either of their structural properties by means of XRD measurements or of the film morphology with the AFM microscope and the electrical response of the thin film towards toxic and pollutant gases were presented.
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Tungsten trioxide (WO3) sputtered thin films for a NOx gas sensor
TL;DR: In this article, the sensing characteristics of the NOx gas detector based on tungsten trioxide (WO3) thin films are reported, where the d.c. electrical response to different gases of the WO3 thin films has been measured in the temperature range from 100 to 400°C showing an increase of electrical resistance with a good sensitivity towards NOx gases at 250°C.
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How can sensitive and selective semiconductor gas sensors be made
TL;DR: The theoretical and practical background of the realization of highly sensitive and selective semiconductor gas sensors is discussed in this paper, where the most important items are the quality of the semiconductor surface, the role of additives (catalytically active materials), the size of crystals or the layer thickness compared to the Debye length of a semiconductor.