Temperature effects on the size of anatase crystallites in MoTiO2 and WTiO2 powders

Bregani, F.; Casale, C.; Depero, Laura E.; Natali-Sora, I.; Robba, D.; Sangaletti, L.; Toledo, Gian Pietro

doi:10.1016/0925-4005(96)80011-6

Cited by 46 publications

(18 citation statements)

References 33 publications

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“…74 The temperature for transformation can be improved by accumulation impurities into TiO 2 . Anatase phase for powder samples containing V, Mo, & W respectively completely disappeared 75 at temperature about 530, 680, and 830 C.…”

Section: Mott Transitionmentioning

confidence: 98%

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Recent advances in syntheses, properties and applications of TiO₂nanostructures

et al. 2018

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Section: Mott Transitionmentioning

confidence: 98%

“…Fig. 3 shows phase transition in TiO 2 n-type semiconductor [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75]…”

Section: Brookitementioning

confidence: 99%

Recent advances in syntheses, properties and applications of TiO₂nanostructures

et al. 2018

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“…TiO 2 is used extensively as a gas sensing material due to its change in electrical conductivity under analyte gas exposure. Sensing capability has been improved with the addition of foreign atoms such as Cr [ 1 ], Mo and W [ 2 ], Pt and Nb [ 3 ], Fe [ 4 ], and La and Cu [ 5 ]. Nb doping of TiO 2 has been used for O 2 , CO, NO 2 , and ethanol sensing.…”

Section: Introductionmentioning

confidence: 99%

Flame-Made Nb-Doped TiO2 Ethanol and Acetone Sensors

Phanichphant

Liewhiran

Wetchakun

et al. 2011

Sensors

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Undoped TiO2 and TiO2 nanoparticles doped with 1–5 at.% Nb were successfully produced in a single step by flame spray pyrolysis (FSP). The phase and crystallite size were analyzed by XRD. The BET surface area (SSABET) of the nanoparticles was measured by nitrogen adsorption. The trend of SSABET on the doping samples increased and the BET equivalent particle diameter (dBET) (rutile) increased with the higher Nb-doping concentrations while dBET (anatase) remained the same. The morphology and accurate size of the primary particles were further investigated by high-resolution transmission electron microscopy (HRTEM). The crystallite sizes of undoped and Nb-doped TiO2 spherical were in the range of 10–20 nm. The sensing films were prepared by spin coating technique. The mixing sample was spin-coated onto the Al2O3 substrates interdigitated with Au electrodes. The gas sensing of acetone (25–400 ppm) was studied at operating temperatures ranging from 300–400 °C in dry air, while the gas sensing of ethanol (50–1,000 ppm) was studied at operating temperatures ranging from 250–400 °C in dry air.

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“…Niobium seemingly facilitated conversion to the rutile phase according to some results reported in the literature. [17] However, since Nb-added powders were partially in rutile phase, no firm statement can be made. In order to show how the size of the grains determines the behavior of the material, we tested the layers as gas sensors.…”

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confidence: 99%

Preparation and Characterization of Nanostructured Titania Thick Films

Carotta

Ferroni

Guidi³

et al. 1999

Adv. Mater.

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The extraordinary modification of bulk-material properties provided by nanosized materials, due to magnification of surface effects, has encouraged the scientific community to seek novel methodologies of synthesis. Among these, particular emphasis has been given to the techniques that envisage large-scale production and could improve the present-day technology.Nanostructured titania films possess an immense range of applications, e.g. in the field of optics, [1] electrical insulation, [2] photovoltaic solar cells, [3] electrochromic displays, [4] antibacterial coatings, [5] photocatalytic reactors, [6] high-performance anodes in ion batteries, [7] and for gas sensing.[8]Indeed, the production of nanostructured titania thin films has been recently carried out by several methods. [9,10] It was also shown that some applications greatly benefited from a nanostructured phase for TiO 2 .[11]However, production of TiO 2 layers via thick-film technology would allow implementation of high-performance devices at very low cost. It is the purpose of this experimental work to show that a nanostructured titania layer can be achieved via thick-film technology. Also shown is the effect of annealing on the nanophase and the role of doping to prevent coarse-grain growth at relatively high temperature.Furthermore, in order to show a possible application, we produced miniaturized devices, onto which the films were deposited. The devices were tested as gas sensors towards CO and the layers with finer grain size turned out to have better performance than coarse-grained films.Thick-film deposition was carried out using screen-printing apparatus equipped with numerically-controlled settings. Achievement of nanosized titania thick films via this technique was a very important goal due to high-reproducibility of the films that can be produced.Thick-films were manufactured using pure TiO 2 and Nb-doped TiO 2 powders produced through laser-induced pyrolysis. This preparation method allowed us to achieve nanometric-sized particles.[12] Experimentally, we found that the best results in terms of film quality and reproducibility were achieved at 80 m 2 /g for the powder. Pure TiO 2 powders were found in anatase phase while Nb-doped ones were a mixture of anatase (80 %) and rutile (20 %). Rutile appeared due to pyrosynthesis at high temperature, which was necessary in order to add Nb to the powders. Detailed descriptions on powder synthesis can be found elsewhere. [13] Commercially available powders were not considered due to too large a grain size and broad distribution of grain dimension, which otherwise would not have allowed one to reach a nanophased film. Previously, preparation of TiO 2 by small-sized powders failed because of the difficulty involved in printing the pastes of such powders and, above all, the appearance of cracks during the drying and firing stages.Printing of the pastes is complicated by the nanometric size of particles, demanding an unusually large quantity of organic vehicle in order to ensure a suitable viscosity. It w...

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Temperature effects on the size of anatase crystallites in MoTiO2 and WTiO2 powders

Cited by 46 publications

References 33 publications

Recent advances in syntheses, properties and applications of TiO₂nanostructures

Recent advances in syntheses, properties and applications of TiO₂nanostructures

Flame-Made Nb-Doped TiO2 Ethanol and Acetone Sensors

Preparation and Characterization of Nanostructured Titania Thick Films

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Temperature effects on the size of anatase crystallites in MoTiO2 and WTiO2 powders

Cited by 46 publications

References 33 publications

Recent advances in syntheses, properties and applications of TiO2nanostructures

Recent advances in syntheses, properties and applications of TiO2nanostructures

Flame-Made Nb-Doped TiO2 Ethanol and Acetone Sensors

Preparation and Characterization of Nanostructured Titania Thick Films

Contact Info

Product

Resources

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Recent advances in syntheses, properties and applications of TiO₂nanostructures

Recent advances in syntheses, properties and applications of TiO₂nanostructures