Surface gas sensing kinetics of a WO3 nanowire sensor: part 1—oxidizing gases

Vuong, Nguyen Minh; Kim, Dojin; Kim, Hyojin

doi:10.1016/j.snb.2015.06.031

Cited by 43 publications

(27 citation statements)

References 23 publications

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“…This ionosorption, or adsorption of molecules as ionic form via the charge-exchange, modifies the electrical conductance of the oxide material, thus leading to the sensor signal by the ratio of the material conductances before and after the gas exposure 1 2 3 . Since the ionosorption reactions are the surface phenomena, the nanostructural forms of the materials increase the sum of the surface reactions, and consequently, the sensor signals 4 5 6 7 8 9 . Indeed, high performance sensors were enabled by the nanostructural materials 10 11 12 .…”

mentioning

confidence: 99%

NO gas sensing kinetics at room temperature under UV light irradiation of In2O3 nanostructures

Chinh

Quang

Lee

et al. 2016

Sci Rep

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106

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In2O3 nanostructure sensors were fabricated by arc-discharging a source composed of a graphite tube containing indium. The NO gas sensing properties, as well as the morphology, structure, and electrical properties, were examined at room temperature under UV light illumination. In particular, the response and recovery kinetics of the sensor at room temperature under various UV light intensities were studied. The maximum response signal was observed at an intermediate UV light intensity, which could be corroborated by a nano-size effect based on the conduction model of a resistive chemical nano sensor. The mechanism for the enhanced adsorption/desorption kinetics for NO in an air environment under UV light irradiation is discussed in detail. Furthermore, the general requirements of the sensor, including the stability, repeatability, and selectivity, are discussed.

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mentioning

confidence: 99%

NO gas sensing kinetics at room temperature under UV light irradiation of In2O3 nanostructures

Chinh

Quang

Lee

et al. 2016

Sci Rep

Self Cite

106

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“…The conductance of the sensing layer is basically determined by temperature and by some electronic molecular mechanisms based on the adsorption and ionization processes of the gases present in the surrounding atmosphere [10]. The adsorbed molecules create some localized energy levels that appear in the forbidden gap of the band diagram, known as extrinsic surface states.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the dynamics of an active control of the surface potential in metal oxide gas sensors

Monge-Villora

Domínguez-Pumar

Olm

2018

Computers & Chemical Engineering

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Gas sensing is nowadays a key actor in pollution observation and detection of chemical toxic agents or explosives. All these applications require the shortest possible time response. Very recently, a control of the surface potential in gas sensors based on metal oxides has experimentally shown to dramatically improve the time response of metal-oxide gas sensors. The proposed control is inspired in sigma-delta modulators. This paper aims at studying the resulting dynamics in the sensor from a theoretical point of view. Using state space models, it is shown how the state variables, namely the concentrations of ionized species in the sensing layer, evolve with time in open and closed loop configuration. This analysis studies how it is possible to alter the dynamics of the overall system, while at the same time keeping some important characteristics of sigma-delta modulators, such as quantization noise-shaping. Numerical simulations validate the obtained results.

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“…You et al successfully synthesized the nanosheets assembled hierarchical WO 3 hollow microspheres by sintering acid‐treated CaWO 4 hollow microspheres precursor at 500 °C, and the response to 40 ppb NO 2 was about 16 at 75 °C. Vuong et al studied the gas sensing mechanism of a 1D highly porous WO 3 nanowire gas sensor, which was based on adsorption–desorption kinetics of oxidizing gases. However, the gas sensing properties of WO 3 /ZnO composite were rarely reported.…”

Section: Introductionmentioning

confidence: 99%

Enhanced NO_x Gas Sensing Properties of Ordered Mesoporous WO₃/ZnO Prepared by Electroless Plating

Han

Wang

et al. 2017

Adv Materials Inter

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NO x gas, and the study on ZnO-based gas sensors attracted the researchers largely. Hitherto, the researchers have synthesized ZnO with different morphology, including nanorods, [9] nanosheets, [10] nanotubes, [11] nanoparticles, [12] nanoplates, [13] nanofilms, [14] and so forth. [15][16][17][18][19][20][21][22][23][24] The different morphology has the considerable impact on the gas sensing performance of MOS gas sensors. A large number of researches indicated that the doped-ZnO materials showed the better performance. The doping components mainly included SnO 2 , WO 3 , Cr 2 O 3 , Co 3 O 4 , Ni, noble metal, etc. [9][10][11][25][26][27][28][29][30][31][32][33][34] Renitta and Vijayalakshmi [30] fabricated a novel nanowhiskers array of Cr incorporated ZnO on ITO substrate by spray pyrolysis technique, and the material exhibited high sensing response to hydrogen gas at room temperature. Liu et al. [28] synthesized Co 3 O 4 /ZnO nanocomposites by an easy wet-chemistry route, and the obtained nanocomposite showed enhanced gas sensing response (about 46%) to 100 ppm ethanol at 170 °C. Tamaekong et al. [31] successfully produced ZnO nanoparticles doped with 0.2-2 at% Pt by flame spray pyrolysis technique. They found that the 0.2 at% Pt/ZnO sensing film showed the highest sensitivity (2.9%) and the fastest response time (≈10 s) to 1000 ppm CO at 350 °C.WO 3 -based gas sensors were widely studied recent years. Zeng et al. [35] prepared a porous WO 3 sensor by anodic oxidation of DC magnetron sputtered metallic tungsten (W) film on alumina substrate. The prepared WO 3 sensor achieved the maximum response toward NO 2 at a low operating temperature of 150 °C. You et al. [36] successfully synthesized the nanosheets assembled hierarchical WO 3 hollow microspheres by sintering acid-treated CaWO 4 hollow microspheres precursor at 500 °C, and the response to 40 ppb NO 2 was about 16 at 75 °C. Vuong et al. [37] studied the gas sensing mechanism of a 1D highly porous WO 3 nanowire gas sensor, which was based on adsorption-desorption kinetics of oxidizing gases. However, the gas sensing properties of WO 3 /ZnO composite were rarely reported. Tesfamichael et al. [32] prepared W-doped ZnO thin films by magnetron sputtering method. The response time of the W-doped ZnO thin film was 195 s toward 5 ppm NO 2 at 150 °C. Naik et al. [23] synthesized a kind of composite MOS sensor array based on tungsten oxide (WO 3 ) and zinc oxide (ZnO) using a simple mechanical mixing method. The highest response of the composite was 148 toward 800 ppb NO 2 at 300 °C.A kind of novel n-n combined ordered mesoporous WO 3 /ZnO (OM-WO 3 / ZnO) sensor are successfully fabricated in this study. A soft-template method is used to synthesize the ordered mesoporous ZnO matrix. Surfaces of the ZnO matrix are innovatively modified using silane coupling agent (mark as: OM-ZnO-Si), and then a layer of WO 3 film is assembled on the surfaces of the OM-ZnO-Si by chemical plating method for the first time, and the OM-WO 3 /ZnO material is obtained. The prepared OM-WO 3 ...

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Surface gas sensing kinetics of a WO3 nanowire sensor: part 1—oxidizing gases

Cited by 43 publications

References 23 publications

NO gas sensing kinetics at room temperature under UV light irradiation of In2O3 nanostructures

NO gas sensing kinetics at room temperature under UV light irradiation of In2O3 nanostructures

Analysis of the dynamics of an active control of the surface potential in metal oxide gas sensors

Enhanced NO_x Gas Sensing Properties of Ordered Mesoporous WO₃/ZnO Prepared by Electroless Plating

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Surface gas sensing kinetics of a WO3 nanowire sensor: part 1—oxidizing gases

Cited by 43 publications

References 23 publications

NO gas sensing kinetics at room temperature under UV light irradiation of In2O3 nanostructures

NO gas sensing kinetics at room temperature under UV light irradiation of In2O3 nanostructures

Analysis of the dynamics of an active control of the surface potential in metal oxide gas sensors

Enhanced NOx Gas Sensing Properties of Ordered Mesoporous WO3/ZnO Prepared by Electroless Plating

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Enhanced NO_x Gas Sensing Properties of Ordered Mesoporous WO₃/ZnO Prepared by Electroless Plating