Soft-chemical synthesis, characterization and humidity sensing behavior of WO3/TiO2 nanopowders

dc.contributorUniversidade Estadual Paulista (UNESP)
dc.creatorZanetti, S. M.
dc.creatorRocha, K. O.
dc.creatorRodrigues, J. A J
dc.creatorLongo, Elson
dc.date2014-05-27T11:30:53Z
dc.date2016-10-25T18:55:10Z
dc.date2014-05-27T11:30:53Z
dc.date2016-10-25T18:55:10Z
dc.date2014-01-01
dc.date.accessioned2017-04-06T02:42:38Z
dc.date.available2017-04-06T02:42:38Z
dc.identifierSensors and Actuators, B: Chemical, v. 190, p. 40-47.
dc.identifier0925-4005
dc.identifierhttp://hdl.handle.net/11449/76940
dc.identifierhttp://acervodigital.unesp.br/handle/11449/76940
dc.identifier10.1016/j.snb.2013.08.053
dc.identifierWOS:000326687700006
dc.identifier2-s2.0-84884261463
dc.identifierhttp://dx.doi.org/10.1016/j.snb.2013.08.053
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/897621
dc.descriptionTungsten oxide/titania (WO3/TiO2) nanopowders were synthesized by the polymeric precursor method which varied the WO3 content between 0 and 10 mol%. The powders were thermally treated in a conventional furnace and their structural, microstructural and electric properties were evaluated by X-ray diffraction (XRD), Raman spectrometry, N 2 physisorption, NH3 chemisorption, temperature-programmed reduction (TPR), X-ray absorption near-edge spectroscopy (XANES) in situ XANES and extended X-ray absorption fine structure spectroscopy (EXAFS) and transmission electron microscopy (TEM). XRD and Raman spectrometry confirmed the homogeneous distribution of an amorphous WO3 phase in the TiO 2 matrix which stabilized the anatase phase through the generation of [TiO5·V0] or [TiO5·V 0] complex sites. Conventional TPR-H2 (temperature programmed reduction) along with XANES TPR-H2 and XANES TPR-EtOH showed that WO3/TiO2 sample reduction occurs through the formation of these complex clusters. Moreover, the addition of WO3 promoted an increase in the surface acidity of doped samples as revealed by NH3 chemisorption. The WO3/TiO2 bulk-ceramic samples were further used to estimate their potential application in a humidity sensor in the range of 15-85% relative humidity. Probable reasons that lead to the different humidity sensor responses of samples were given based on the structural and surface characterizations. Correlation between the sensing performance of the sensor and its structural features are also discussed. Although all samples responded as a humidity sensor, the W2T sample (2 mol% added WO3) excelled for sensitivity due to the increase in acid sites, optimum mean pore size and pore size distribution. © 2013 Elsevier B.V.
dc.languageeng
dc.relationSensors and Actuators B: Chemical
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.subjectChemical synthesis
dc.subjectEXAFS
dc.subjectHumidity sensor
dc.subjectIn situ XANES
dc.subjectPolymeric precursor method
dc.subjectWO3/TiO 2
dc.subjectExtended Xray absorption fine structure (EXAFS) spectroscopies
dc.subjectPolymeric precursor methods
dc.subjectSitu XANES
dc.subjectStructural and surface characterization
dc.subjectTemperature-programmed reduction
dc.subjectX-ray absorption near edge spectroscopy
dc.subjectChemisorption
dc.subjectElectric properties
dc.subjectExtended X ray absorption fine structure spectroscopy
dc.subjectHumidity sensors
dc.subjectNanostructured materials
dc.subjectPolymers
dc.subjectPore size
dc.subjectSpectrometry
dc.subjectSynthesis (chemical)
dc.subjectTransmission electron microscopy
dc.subjectX ray diffraction
dc.subjectX ray powder diffraction
dc.subjectTitanium dioxide
dc.titleSoft-chemical synthesis, characterization and humidity sensing behavior of WO3/TiO2 nanopowders
dc.typeOtro


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