Porous alumina thin layers using mesophase templating

Idrissi-Kandri, Noureddine; Ayral, A.; Klotz, Michaela; Albouy, Pierre‐Antoine; Mansouri, A. El; Lee, Arie van der; Guizard, C.

doi:10.1016/s0167-577x(00)00413-4

Cited by 19 publications

(10 citation statements)

References 10 publications

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“…Mesoporous TiO 2 has been prepared as bulk powders and films [6,7]. An interesting method to fabricate highly porous materials with desired pore structure and size for target specific applications is the use of amphiphilic organic molecules such as surfactants and block copolymers as pore directing agents in sol-gel methods [8]. Our motivation is to explore an effective technique to construct the oriented organization of nanoparticles, which is based on creating an interfacial interaction by chemical modification on the surfaces of nanoparticles (or micelle formation, that is, form colloidal-size cluster in solution called micelles which depend on surfactant concentration and salt concentration).…”

Section: Introductionmentioning

confidence: 99%

Preparation and Application of Mesoporous Nanotitania Photocatalysts Using Different Templates and pH Media

Abdel-Azim

Aboul-Gheit

Ahmed

et al. 2014

International Journal of Photoenergy

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Mesoporous nanotitania photocatalysts were prepared by sol-gel method in acidic or basic media. Three types of surfactants, namely, cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and nonylphenol ethoxylate, were used as templating agents. The effects of surfactant type and pH on the morphology, particle size, surface area, pore-size distribution, UV-Vis absorbance, and TiO2phase transformation were traced by SEM, TEM, BET, and XRD. In absence of surfactants, XRD revealed 54.5% anatase at pH 3-4 and 97.0% at pH 7–9. In presence of surfactant, phase transformation of anatase has been significantly inhibited such that anatase amounts to 82–100% in acidic media. In basic media, the brookite phase appeared in low concentrations (8–15%) while rutile totally disappeared. The photocatalytic performance of the synthesized catalysts was tested via naphthalene degradation, which exhibited high activity in visible irradiation (>400 nm). The data obtained indicate that the surface area and pore volume of the current catalysts are the most effective factors for photocatalytic performance. Nevertheless, at the low pH (acidic) range, the CTAB templated catalyst gave the highest surface area (86.7 cm3/g), which is mainly assigned to acquiring the highest photocatalytic degradation of naphthalene (97% after 4 h irradiation time).

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Section: Introductionmentioning

confidence: 99%

Preparation and Application of Mesoporous Nanotitania Photocatalysts Using Different Templates and pH Media

Abdel-Azim

Aboul-Gheit

Ahmed

et al. 2014

International Journal of Photoenergy

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“…It has been reported that addition of certain inorganic materials, including alumina, silica, and activated carbon would inhibit the crystal phase transformation of TiO 2 material and enhance its thermal stability [16][17][18][19]. Although amphiphilic organic molecules (i.e., surfactants) have been extensively used in sol-gel methods to control structural properties of materials, there has been no attempt to investigate the effect of adding organic molecules into a sol considering beneficial aspects such as those in the case of inorganic additives [20][21][22][23][24][25]. For example, in the sol-gel methods modified with surfactants, the as-synthesized amorphous TiO 2 material has high surface area but weak inorganic network walls.…”

Section: Introductionmentioning

confidence: 99%

“…During heat treatment for removing organic templates and increasing materials crystallinity, this material undergoes thermal nucleation and crystal growth of the anatase phase. This results in the destruction of pore structure, reduction of surface area, and formation of the rutile phase [24,25]. As a result, such studies have mainly focused on the low temperature preparation of mesoporous TiO 2 inorganic network with high surface area but low crystallinity [23].…”

Section: Introductionmentioning

confidence: 99%

Effect of surfactant in a modified sol on the physicochemical properties and photocatalytic activity of crystalline TiO2 nanoparticles

2007

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This study describes the effect of amphiphilic organic molecules (surfactants) in a sol on the physicochemical properties and photocatalytic activity of crystalline TiO 2 nanoparticles prepared via a simple sol-gel route at high temperatures from 400 to 800°C. Addition of polyoxyethylenesorbitan surfactant and polyethylene oxide and polypropylene oxide triblock copolymer as particle size inhibitors and pore directing agents into a stable titania sol affected the physicochemical properties of TiO 2 nanoparticles such as their crystallographic structure, morphology, and defect structure. With the addition of the surfactants, the ratio of anatase and rutile crystal phases of TiO 2 was controlled and an active anatase crystal phase was maintained during heat treatment up to 800°C. Decrease in the sintering rate and inhibition in crystal growth were also observed, which resulted in higher surface area and inhibition of crystallite aggregation. Bulk defects in TiO 2 were reduced while surface defects were increased as a result of the addition of surfactants. These physicochemical properties of TiO 2 nanoparticles were correlated with photocatalytic degradation of 4-chlorophenol in water. The results revealed that high crystallinity, anatase crystal phase, high specific surface area, surface defects, and segregated morphology of TiO 2 nanoparticles, which were induced by the addition of surfactants, were more advantageous for enhancing photocatalytic destruction of the model organic compound tested in the study.

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“…One of the most promising applications for these membranes should be in membrane reactors. Very encouraging results have been obtained by this method on templated mesoporous alumina (Idrissi-Kandri et al 2001) and titania (Bosc et al 2003) supported layers which point to the development of new ceramic oxide membranes with tailor-made mesoporous structures.…”

Section: Inorganic Membranesmentioning

confidence: 90%