Crystalline structure, defects and gas sensor response to NO2 and H2S of tungsten trioxide nanopowders

Jiménez, I.; Arbiol, Jordi; Dezanneau, G.; Cornet, A.; Morante, J.R.

doi:10.1016/s0925-4005(03)00198-9

Cited by 204 publications

(86 citation statements)

References 29 publications

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“…Of the methods used to prepare these oxides, those that are most commonly cited in the literature require the use of thin films (< 1 micrometer). However, in some cases thick films are used, doped with noble metals or various nanoshapes designed to effect grain boundaries [18][19][20][21][22][23][24][25]. These metal oxide sensors must be heated to elevated temperatures that range from 100 to 600°C [18,[26][27][28] which, in many cases for the effective monitoring of a given analyte, must be precisely controlled.…”

Section: The Interfacementioning

confidence: 99%

Nanostructure directed interfaces created from nanoparticle island sites deposited to microporous arrays and forming sensor platforms

Gole¹,

Laminack²,

Boudreaux³

2017

Front Nanosci Nanotech

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Novel nanostructured island sites are made to decorate a microporous/nanoporous array. These island sites are formed from a variety of easily produced nanostructured metal oxides deposited from solution. Sensor platforms are distinct from and do not require film-based coating. The nanostructure directing acidic metal oxide sites which vary in their Lewis acidity decorate micropores and control the electron transduction process. The interaction of analytes with these island sites varies in a predictable manner and can be modified through in-situ functionalization of their Lewis acidity. The microporous structure allows rapid Fickian diffusion of analytes to the active nanostructure island sites whose reversible interaction dominates the sensor response as it requires low energy consumption. Highly accurate repeat depositions are not required. We require that the island sites are deposited at sufficiently low concentration so as not to interact electronically with each other. The response time of these interfaces is more rapid than film-based depositions, which require a more lengthy diffusion time. The sensors are reversible. The nanoporous structure prevents sintering of these island centers at elevated temperatures. The concentration of detection centers can be made to produce an optimum matrix of enhanced sensor responses, force a dominant distinct analyte-interface physisorption (rather than chemisorption). The produced semiconductor interface is easily functionalized to create an enhanced range of nanoparticle semiconductor sites. The matrix provides a sensitive means of transferring electrons that are easily detected. The sensors operate at room temperature as well as elevated temperatures. Low energy magnetic field signal enhancement can be achieved with transition metals. Contaminated sensors can be readily rejuvenated. Pulsed mode operation ensures low analyte consumption and high analyte selectivity and further provides the ability to rapidly assess false positive signals using Fast Fourier Transfer techniques, Solar pumped sensors requiring low light levels (≤ 1 Watt) have been demonstrated. Water vapor contamination can be greatly if not entirely reduced. The modelling of sensor response with a new Fermi energy distribution -based response isotherm is found to be superior to other isotherms. Sensors operate can be made to operate efficiently for two gases simultaneously. Modes of extending these studies to multiple gas arrays are considered.

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Section: The Interfacementioning

confidence: 99%

Nanostructure directed interfaces created from nanoparticle island sites deposited to microporous arrays and forming sensor platforms

Gole¹,

Laminack²,

Boudreaux³

2017

Front Nanosci Nanotech

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“…The most commonly cited types of oxide sensors in the literature are based off thin films (<1 micrometer). However, in some cases thick films are used, doped with noble metals or various nanoshapes designed to effect grain boundaries [13][14][15][16][17][18][19][20]. These metal oxide sensors must be heated to elevated temperatures that range from 100 to 600°C depending on the analyte [13,[21][22][23].…”

Section: Introductionmentioning

confidence: 99%

New Generation Devices for Gas (Liquid) Sensing

Jl¹,

Laminack²

2016

J Phys Chem Biophys

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“…As a comparison, transmission electron microscope (TEM) was used to investigate the size of the WO 3 nanoparticles. The result from XRD and DTA show that the formation of polymorphs WO 3 nanoparticles have the following sequence: orthorhombic (-WO 3 )  monoclinic (-WO 3 )  triclinic (-WO 3 )  monoclinic (-WO 3 ) with respect to the calcination temperature of 400, 500, 600 and 700C. No diffraction peaks were found in the X-Ray diffraction measurements for the sample heat treated at 300C (as-prepared), suggesting that an amorphous structure was obtained at this temperature whereas the crystallinity had been obtained by the other samples of the WO 3 nanoparticles at the calcination temperatures of 400, 500, 600 and 700C.…”

mentioning

confidence: 99%

S tudies on the phase transitions and properties of tungsten (VI) oxide nanoparticles by X - Ray diffraction (XRD) and thermal analysis

Abdullah¹,

Radiman²,

Hamid³

et al. 2017

AJSTD

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Tungsten (VI) oxide, WO 3 nanoparticles were synthesized by colloidal gas aphrons (CGAs) technique. The resultant WO 3 nanoparticles were characterized by thermogravimetric-differential thermal analysis (TG-DTA) and X-Ray diffraction (XRD) measurements in order to determine the phase transitions, the crystallinity and the size of the WO 3 nanoparticles. As a comparison, transmission electron microscope (TEM) was used to investigate the size of the WO 3 nanoparticles. The result from XRD and DTA show that the formation of polymorphs WO 3 nanoparticles have the following sequence: orthorhombic (-WO 3 )  monoclinic (-WO 3 )  triclinic (-WO 3 )  monoclinic (-WO 3 ) with respect to the calcination temperature of 400, 500, 600 and 700C. No diffraction peaks were found in the X-Ray diffraction measurements for the sample heat treated at 300C (as-prepared), suggesting that an amorphous structure was obtained at this temperature whereas the crystallinity had been obtained by the other samples of the WO 3 nanoparticles at the calcination temperatures of 400, 500, 600 and 700C. It is also found that the X-Ray diffraction measurements produced an average diameter of (30  5), (50  5), (150  10) and (200  10) nm at calcination temperatures of 400, 500, 600 and 700C respectively by using Debye-Scherrer formula. The TG curve revealed that the WO 3 nanoparticles is purely anhydrous since the weight loss is insignificant (0.3 -1.4) % from 30 until 600C for the WO 3 nanoparticles calcined at 400C. Finally, the composition and the purity of the WO 3 nanoparticles have been examined by X-Ray photoelectron spectroscopy (XPS). The results indicate no significant changes to the composition and the purity of the WO 3 nanoparticle produced due to the temperature variations.

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Crystalline structure, defects and gas sensor response to NO2 and H2S of tungsten trioxide nanopowders

Cited by 204 publications

References 29 publications

Nanostructure directed interfaces created from nanoparticle island sites deposited to microporous arrays and forming sensor platforms

Nanostructure directed interfaces created from nanoparticle island sites deposited to microporous arrays and forming sensor platforms

New Generation Devices for Gas (Liquid) Sensing

S tudies on the phase transitions and properties of tungsten (VI) oxide nanoparticles by X - Ray diffraction (XRD) and thermal analysis

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