Mesoporous TiO2–SiO2 aerogels with hierarchal pore structures

Yao, Nan; Cao, Sheng‐Li; Yeung, King Lun

doi:10.1016/j.micromeso.2008.08.020

Cited by 137 publications

(49 citation statements)

References 64 publications

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“…Pure kaolinite exhibited an isotherm with a sharp adsorbent uptake near P/P o = 1 signifying the presence of macropores. On the other hand, pure TiO 2 , as-synthesized and calcined samples of K-TiO 2 possess type IV isotherms depicting the presence of a mesoporous structure [28,41,42]. Indeed, their hysteresis loops are centered at relative pressures of 0.32 < P/P o < 0.85 representing the absence of macropores.…”

Section: Nitrogen Gas Physisorption Studiesmentioning

confidence: 99%

Sol–gel synthesis of photoactive kaolinite-titania: Effect of the preparation method and their photocatalytic properties

Shao

Engole

Imran

et al. 2015

Applied Surface Science

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Section: Nitrogen Gas Physisorption Studiesmentioning

confidence: 99%

Sol–gel synthesis of photoactive kaolinite-titania: Effect of the preparation method and their photocatalytic properties

Shao

Engole

Imran

et al. 2015

Applied Surface Science

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“…[11,12] Changing the experimental conditions and applying heat treatment influence the final composition and microstructure of the material. [13]Anatase nucleates grow first during the sol-gel process.However, calcination at higher temperatures induces a phase transformation from anatase to the thermodynamically more stable rutile. [14]The photocatalytic activity of mesoporous titania and titania-silica composites synthesized by the sol-gel method is recently a hot topic of materials research.…”

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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“…Adsorption-desorption profiles of RHA and TS-RHA are consistence to the type IV adsorption isotherm with H3 hysterisis loop while TS-TEOS is fit to H4 refer to IUPAC classification. The type IV is associated with the presence of framework structure of mesopore and H3 hysterisis loop is identified for slit shaped mesopore [10,14]. From Table 2, the formation of TiO2-SiO2 has higher specific area and pore volume compared to RHA.…”

Section: Resultsmentioning

confidence: 96%

“…Considering that silica can be obtained from rice husk ash (RHA), the synthesis of TiO2-SiO2 by RHA is interesting topic. The isolation of silica from RHA has been reported by some previous investigation [9][10][11]. The possibility to attach titania with silica framework by using solgel mechanism can be utilized to create nanosized TiO2-SiO2.…”

Section: Introductionmentioning

confidence: 93%

Preparation of TiO2-SiO2 using Rice Husk Ash as Silica Source and The Kinetics Study as Photocatalyst in Methyl Violet Decolorization

Fatimah

Said

Hasanah

2014

Bull. Chem. React. Eng. Catal.

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Preparation, characterization and utilization of TiO2-SiO2 as photocatalyst for methyl violet (MV) decolorization has been conducted. In this research, preparation of TiO2-SiO2 was developed based on natural renewable silica source; rice husk ash (RHA) via a sol-gel technique. The composite was formed by the dispersing of titanium isopropoxide as titania precursor into the gel of silica followed by aging, drying and calcination. The TiO2-SiO2 sample was characterized by powder X-ray diffraction (XRD), diffuse reflectance-UV Visible spectrophotometric analysis (DRUV-Vis), gas sorption analyzer and Scanning electron micrograph (SEM) before its utilization as photocatalyst in methyl violet photooxidation. As comparison to the physicochemical character study, the synthesis of TiO2-SiO2 by using tetraethyl ortosilicate (TEOS) was performed as a confirmation. Result showed that prepared TiO2-SiO2 has the character similar to TiO2-SiO2 as synthesized by TEOS precursor. The formation of crystalline titania in anatase and rutile phase was identified with increasing surface porosity data and the value of band gap energy which sufficiently contribute to a photocatalytic mechanism. The character data are in line with the kinetic data of methyl violet decolorization. From the compared photooxidation, photolysis, photocatalysis and adsorption process, it can be concluded that TiO2-SiO2 acts efficiently as a photocatalyst.

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Mesoporous TiO2–SiO2 aerogels with hierarchal pore structures

Cited by 137 publications

References 64 publications

Sol–gel synthesis of photoactive kaolinite-titania: Effect of the preparation method and their photocatalytic properties

Sol–gel synthesis of photoactive kaolinite-titania: Effect of the preparation method and their photocatalytic properties

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

Preparation of TiO2-SiO2 using Rice Husk Ash as Silica Source and The Kinetics Study as Photocatalyst in Methyl Violet Decolorization

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