The study of photocatalytic activities of titania and titania–silica aerogels

Malinowska, B; Walendziewski, Jerzy; Robert, Didier; Weber, J.V.; Stolarski, Marek

doi:10.1016/s0926-3373(03)00273-x

Cited by 70 publications

(33 citation statements)

References 42 publications

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“…[15,16,17,18,19,20,21,22]Pure titania aerogels were shown to be more efficient photocatalysts than titania-silica aerogels.However, it should be emphasized, thatcomposite aerogels usually lack the structural homogeneity of TiO 2 and SiO 2 phases on the atomic scale. [23,24] In other words, some micro-or nanocrystalline TiO 2 , usually in the form of anatase, is always present dispersed in the structure, and this crystalline phase is responsible for the photocatalytic effect.In this work we present a family of titaniasilica aerogels in which no crystalline TiO 2 can be detected by X-ray diffraction methods.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Lázár

Kalmár

Peter

et al. 2015

Applied Surface Science

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Abstract. Titania-silica composite aerogels with 16 -29% Ti-content by the mass were synthesized by the sol-gel method from different Ti-precursors, and calcined at 500°C. These aerogels are highly amorphous as no crystalline TiO 2 phase can be detected in them by X-ray diffraction methods, and show the dominating presence of either mesopores or macropores.The incorporation of Ti into the silica structure is shown by the appearance of characteristic IR transitions of Si-O-Ti vibrations.The characteristic band-gap energies ofthe different aerogelsare estimated to be between 3.6 and 3.9 eV from UV reflection spectra. Band-gap energy decreases with decreasing pore-size. When suspended in solution,even these highly amorphous aerogels accelerate the photodegradation of salicylic acid and methylene blue compared to simple photolysis. Kinetic experiments were conducted under illumination, and also in the dark to study the adsorption of the substrates onto the suspended aerogels.We assume that the fast in-situadsorption of the organic substratesmask the suspended aerogel particles from UV photons,which reduces the rate of photocatalysis. We managed to mathematically separate the parallelprocesses of photocatalysis and adsorption, and develop a simple kinetic model to describe the reaction system.

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Section: Introductionmentioning

confidence: 99%

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Lázár

Kalmár

Peter

et al. 2015

Applied Surface Science

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“…Many works have been concerned with the application of TiO 2 /SiO 2 materials in photocatalytic processes [14][15][16][17][18][19][20][21][22][23][24][25][26]. TiO 2 /SiO 2 powders have been often prepared to make easier the separation of the catalyst after the photocatalytic reaction but these photocatalysts are commonly less active than bare TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic activity of TiO2/SiO2 systems

Bellardita

Addamo

Paola

et al. 2010

Journal of Hazardous Materials

118

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“…It is well known that band gap energy of pure anatase is higher than bulk rutile TiO2, and thus the unique anatase content of the biotemplated samples result in a raise in band gap energy [15]. Besides, Jafry et al [7] and Malinowska et al [25] presented that the change in the band gap energy of TiO2-SiO2 composites, prepared by an in situ doping of SiO2, results from the reduction of valence band and the increase of conduction band. In this work, the band gap energy seems to be increasing slowly with the change in Si content, which will help to improve the efficiency of electron-hole separation, thus leading to efficient photocatalysis.…”

Section: Studies On Light-harvesting and Photocatalytic Activities Ofmentioning

confidence: 99%

Biotemplated Mesoporous TiO2/SiO2 Composite Derived from Aquatic Plant Leaves for Efficient Dye Degradation

Yan

Guo

et al. 2017

Catalysts

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Abstract:The biotemplating technique is an environmental-protective high-efficiency new technology by which the resulting TiO 2 may simultaneously attain the duplication of structure and self-doping elements from biotemplate materials, which is highly desirable for photocatalytic applications. In this paper, aquatic plant leaves-including reed, water hyacinth, and duckweed-were used as both templates and silicon precursors to successfully synthesize biomorphic TiO 2 /SiO 2 composite with mesoporous structures. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 adsorption-desorption, and UV-visible diffuse reflectance spectra were applied to characterize the microstructures of the samples. The results show that all TiO 2 /SiO 2 composites are mainly composed of an anatase phase with mesoporous structure and possess high specific surface area. Compared with commercial Degussa P25 TiO 2 , all TiO 2 /SiO 2 samples display intensive light-harvesting efficiency, particularly in the visible light range. The activities were evaluated by using gentian violet as a target for photocatalytic degradation experiments under simulated solar irradiation. The TiO 2 /SiO 2 samples templated by reed and water hyacinth leaves exhibit high activity, while the TiO 2 /SiO 2 samples obtained from duckweed are inferior to P25 in the degradation of gentian violet. A synergistic effect of SiO 2 incorporation and structural construction through biotemplating is proposed to be beneficial to photocatalytic activity.

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The study of photocatalytic activities of titania and titania–silica aerogels

Cited by 70 publications

References 42 publications

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Photocatalytic performance of highly amorphous titania–silica aerogels with mesopores: The adverse effect of the in situ adsorption of some organic substrates during photodegradation

Photocatalytic activity of TiO2/SiO2 systems

Biotemplated Mesoporous TiO2/SiO2 Composite Derived from Aquatic Plant Leaves for Efficient Dye Degradation

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