SYNTHESIS AND MICROSTRUCTURE OF A NOVEL TiO2 AEROGEL–TiO2 NANOWIRE COMPOSITE

Suzuki, Yoshikazu; Berger, Marie‐Hélène; D’Elia, Daniela; Ilbizian, Pierre; Beauger, Christian; Rigacci, Arnaud; Hochepied, Jean-François; Achard, Patrick

doi:10.1142/s1793292008001222

Cited by 8 publications

(7 citation statements)

References 22 publications

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“…4) with a water contact angle higher than 150 and self-cleaning properties [113], sulfated zirconia aerogels [114] (Chap. 6), TiO 2 aerogels [115] (Chap. 7), aerogel composites [115], and more exotic chalcogenide aerogels [116] (Chap.…”

Section: Recent Aerogel Developmentsmentioning

confidence: 99%

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History of Aerogels

Pierre¹

2011

Aerogels Handbook

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This chapter presents a historical account of the progressive development of the solid materials known as aerogels. The founding work of Kistler is first summarized. His precursory work attracted the attention of scientists who focused on the physics and chemistry of aerogels, reviewed in the second section. The latter studies allowed for the understanding of how a very high open porosity solid could be maintained when drying a gel and how some specific properties such as transparency or a hydrophobic character could be granted to these materials. In turn, a better knowledge of the scientific basis behind aerogels led to determining their technical characteristics and developing their applications, as addressed in the third section. The most recent developments summarized in the last section aim at a progressive transfer of these applications toward the industry. The Founding Studies by KistlerThe term aerogel was first introduced by Kistler in 1932 to designate gels in which the liquid was replaced with a gas, without collapsing the gel solid network [1]. While wet gels were previously dried by evaporation, Kistler applied a new supercritical drying technique, according to which the liquid that impregnated the gels was evacuated after being transformed to a supercritical fluid. In practice, supercritical drying consisted in heating a gel in an autoclave, until the pressure and temperature exceeded the critical temperature T c and pressure P c of the liquid entrapped in the gel pores.This procedure prevented the formation of liquid-vapor meniscuses at the exit of the gel pores, responsible for a mechanical tension in the liquid and a pressure on the pore walls, which induced gel shrinkage. Besides, a supercritical fluid can be evacuated as gas, which in the end lets the "dry solid skeleton" of the initial wet material. The dry samples that were obtained had a very open porous texture, similar to the one they had in their wet stage.Overall, aerogels designate dry gels with a very high relative or specific pore volume, although the value of these characteristics depends on the nature of the solid and no official convention really exists (Chap. 21). Typically, the relative pore volume is of the order of 90% in the most frequently studied silica aerogels [2]

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Section: Recent Aerogel Developmentsmentioning

confidence: 99%

“…6), TiO 2 aerogels [115] (Chap. 7), aerogel composites [115], and more exotic chalcogenide aerogels [116] (Chap. 17).…”

Section: Recent Aerogel Developmentsmentioning

confidence: 99%

History of Aerogels

Pierre¹

2011

Aerogels Handbook

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“…19 Semiconductor materials with different shapes (spheres, cubes, tubes, wires, rods, sheets and akes), sizes and dimensions can be synthesized by varying the method of preparation and calcination temperature. 20 Suzuki et al 21 suggested that there are still many possibilities for improving the photocatalytic activity of semiconductors, especially by altering their morphology. Campelo et al 22 showed that there are some benets in using nanosized Pd-containing photocatalysts since the Pd nanostructures have enhanced lightharvesting ability.…”

Section: Introductionmentioning

confidence: 99%

Structural and photocatalytic properties of Pd-deposited semiconductors with different morphology

Malkhasian

Narasimharao

2017

RSC Adv.

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“…It is cheap and has been studied for long, especially for application in solar cells [9,10] or for its photocatalytic properties [11,12]. Different morphologies have thus already been developed, nanoparticles, nanotubes or even aerogels [13][14][15][16][17][18][19][20][21][22][23] for instance. Morphology is a major feature of PEMFC catalyst supports, especially at the cathode side, since it governs diffusion limitations related to gas diffusion towards (oxygen) and from (water) catalytic sites inside the cathodic catalyst layer.…”

Section: Graphical Abstract Introductionmentioning

confidence: 99%

Doped TiO 2 aerogels as alternative catalyst supports for proton exchange membrane fuel cells: A comparative study of Nb, V and Ta dopants

Beauger

Testut

Berthon‐Fabry

et al. 2016

Microporous and Mesoporous Materials

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Nb, Ta and V-doped TiO 2 aerogels and xerogels have been synthesized as possible new alternatives to carbon blacks for Proton Exchange Membrane Fuel Cells catalyst supports. A comparative study of different dopants was realized in a single study. Nb, Ta and V showed different behaviors with respect to the final material structure and morphology, composition and electronic conductivity. They are all prone to surface segregation, to different extents. V-doped TiO 2 apart, the rutile structure could only be obtained after calcination in a reducing atmosphere at 800 °C for Nb or Ta-doped TiO 2 . The electronic conductivity exhibited a maximum at 10 at.% for Nb and Ta, 5 at.% for V. Nb revealed to be the most appropriate dopant to increase the electronic conductivity of TiO 2 , followed by Ta and V.4 to 5 orders of magnitude were gained after Nb doping for xerogels conductivity to reach almost 0.1 S cm -1 . The role of point defects was discussed to account for phase transition and evolution of conductivity.

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SYNTHESIS AND MICROSTRUCTURE OF A NOVEL TiO₂ AEROGEL–TiO₂ NANOWIRE COMPOSITE

Cited by 8 publications

References 22 publications

History of Aerogels

History of Aerogels

Structural and photocatalytic properties of Pd-deposited semiconductors with different morphology

Doped TiO 2 aerogels as alternative catalyst supports for proton exchange membrane fuel cells: A comparative study of Nb, V and Ta dopants

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