@Article{ZanettiRochRodrLong:2014:SoSyCh,
author = "Zanetti, Sonia Maria and Rocha, Kleper de Oliveira and Rodrigues,
Jos{\'e} Augusto Jorge and Longo, Elson",
affiliation = "{SENCER - Sensores Cer{\^a}micos Ltda} and {SENCER - Sensores
Cer{\^a}micos Ltda} and {Instituto Nacional de Pesquisas
Espaciais (INPE)} and {Universidade Estadual Paulista (UNESP)}",
title = "Soft-chemical synthesis, characterization and humidity sensing
behavior of WO3/TiO2 nanopowders",
journal = "Sensors and Actuators B: Chemical",
year = "2014",
volume = "190",
pages = "40--47",
keywords = "EXAFS, Extended Xray absorption fine structure (EXAFS)
spectroscopies, Polymeric precursor methods, Situ XANES,
Structural and surface characterization, Temperature-programmed
reduction, WO<sub>3</sub>/TiO <sub>2</sub>, X-ray absorption near
edge spectroscopy, Chemisorption, Electric properties, Extended X
ray absorption fine structure spectroscopy, Humidity sensors,
Nanostructured materials, Polymers, Pore size, Spectrometry,
Synthesis (chemical), Transmission electron microscopy, X ray
diffraction, X ray powder diffraction, Titanium dioxide.",
abstract = "Tungsten 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.",
doi = "10.1016/j.snb.2013.08.053",
url = "http://dx.doi.org/10.1016/j.snb.2013.08.053",
issn = "0250-6874",
label = "scopus 2014-05 ZanettiRochRodrLong:2014:SoSyCh",
language = "en",
targetfile = "1-s2.0-S0925400513009891-main.pdf",
url = "http://dx.doi.org/10.1016/j.snb.2013.08.053",
urlaccessdate = "28 abr. 2024"
}