Polymer Gel Templating of Free-Standing Inorganic Monoliths for Photocatalysis

Fan, Xiaojuan; Fei, Honghan; Demaree, David H.; Brennan, Daniel P.; John, Jessica M. St.; Oliver, Scott R. J.

doi:10.1021/la8029837

Cited by 20 publications

(17 citation statements)

References 22 publications

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“…Hierarchically, porous TiO 2 monoliths are especially important for chromatographic applications because of their selective adsorption of organophosphates, such as nucleotides and phospholipids 23–28 . However, there are only a few reports describing the formation of porous TiO 2 monoliths 29–33 because titanium alkoxide exhibits remarkably high reactivity, which generally leads to the heterogeneous precipitation of TiO 2 rather than the formation of monolithic gels. Konishi et al 32,33 prepared macroporous TiO 2 monoliths from colloidal TiO 2 and titanium alkoxide under a strongly acidic condition.…”

Section: Introductionmentioning

confidence: 99%

Facile Preparation of Hierarchically Porous TiO₂ Monoliths

Hasegawa

Kanamori

Nakanishi

et al. 2010

Journal of the American Ceramic Society

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Monolithic titania (TiO2) with multiscale porous structures have been successfully prepared via the sol–gel route accompanied by phase separation utilizing a chelating agent and mineral salt. The TiO2 gels obtained possess well‐defined macropores derived from spinodal decomposition and mesopores as interstices of anatase TiO2 nanocrystallites. Most of the chelating agent were removed by hydrolysis and subsequent decarbonation through the gradual solvent exchange from ethanol to water. The TiO2 particles comprising TiO2 gel skeletons spontaneously converted from amorphous to anatase through the solvent exchange process in a mild condition at 60°C. The present method of the fabrication of porous TiO2 monoliths is advantageous for widespread applications because the reaction occurs under an almost neutral condition and does not require a hydrothermal process, which was indispensable to strengthen the monolith in the method previously reported.

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Section: Introductionmentioning

confidence: 99%

Facile Preparation of Hierarchically Porous TiO₂ Monoliths

Hasegawa

Kanamori

Nakanishi

et al. 2010

Journal of the American Ceramic Society

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“…18,23,[26][27][28][29] Caruso's group 27 first reported the use of agarose gels to template high-crystalline macroporous metal oxide monoliths. 28 Our group had independently been employing polymer templates to achieve a variety of titania morphologies including monoliths, 27,28 networks, 29 beads, 16,17 and thin films. 18,23 The advantage of this method is that the resultant morphology can, to some degree, be controlled through the choice of polymer, its concentration, degree of swelling, and (or) cross-linking.…”

Section: Introductionmentioning

confidence: 99%

Solid-state dye-sensitized solar cells from polymer-templated TiO₂ bilayer thin films

et al. 2012

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We report an inexpensive method using solvent-swollen poly(methyl methacrylate) as a sacrificial template for mesoporous titanium oxide thin films with tunable meso/nano morphology. The conversion efficiency reaches 4.2% despite using a solid-state electrolyte, which circumvents the longevity issues of liquid electrolytes. The cells show a large shortcircuit photocurrent density of 7.98 mA, open-circuit voltage of 0.78 V, and maximum conversion efficiency of 4.2% under air-mass 1.5 global illumination. At higher titania precursor ratios, nanodisk particles are formed that increase light scattering and double the efficiency over our previous reports. The tunability of the semiconductor morphology and all solid-state nature of the cells makes the method a viable alternative to existing solar cell technology.Résumé : On a mis au point une méthode peu coûteuse de préparation de films minces d'oxyde de titane mésoporeux avec une morphologie ajustable méso/nano qui fait appel à l'utilisation de poly(méthacrylate de méthyle) gonflé par un solvant comme matrice sacrifiée. L'efficacité de la conversion atteint 4,2 % même si on utilise un électrolyte à l'état solide pour contourner les problèmes de longévité des électrolytes liquides. Les cellules permettent de déceler une densité élevée (7,98 mA) de photocourant de court-circuit, un voltage de circuit ouvert de 0,78 V et une efficacité de conversion de 4,2 % sous une illumination globale de 1,5 de la masse d'air. À des rapports plus élevés de blanc de titane, il se forme des particules nanodisques qui augmentent la diffusion de la lumière et dont l'efficacité est égale au double de ce qui avait été rapporté antérieurement. La possibilité de modifier la morphologie du semiconducteur et la nature d'état complètement solide des cellules fait que cette méthode est une alternative viable à la technologie des cellules solaires existantes.Mots-clés : matrice de polymère, film mince d'oxyde de titane, cellule solaire sensibilité par un colorant, poly(méthacrylate de méthyle), nanodisque.[Traduit par la Rédaction]

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“…Previously, agarose gels have been used as templates to produce porous oxides of titanium, zirconium, niobium, and tin, aluminum or vanadium doped titanium oxide, , and zirconium titanium oxide. , The templating process is unaffected by ambient humidity and temperature, allowing for highly reproducible materials. Although agarose gels have proven to work well as templates for porous monolithic metal oxides, the technique was previously ineffective for silica, due to the slow kinetics of the alkoxysilane−silica sol−gel transition at neutral pH.…”

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confidence: 99%

“…The agarose gel structure is not stable in acidic and basic solutions, which could otherwise be used to accelerate the hydrolysis of TEOS . Due to these complications, some have claimed that agarose gels cannot be used as a template for silica . However, these synthetic barriers could potentially be overcome by using a condensation catalyst that functions at neutral pH.…”

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Strong Silica Monoliths with Large Mesopores Prepared Using Agarose Gel Templates

2011

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Mesoporous silica pellets with controllable shape and pore size were prepared using agarose gel templates. Robust (compressive strength of 3.3-25.1 MPa), crack-free silica monoliths have been produced with large mesopores (14-23 nm), high surface areas (410-540 m(2) g(-1)), and large pore volumes (1.1-1.2 cm(3) g(-1)). The synthesis was achieved by infusing preformed agarose gels with tetraethyl orthosilicate and the nonpolar condensation catalyst tetrabutyl ammonium fluoride. The infiltrated gels were transferred to water to initiate hydrolysis and condensation of the silica precursor. Fluoride catalyzed the gelation of silica in a matter of minutes; hence, the oxide maintained the shape of the agarose pellet. The mesopore size could be modified by altering the weight percent of agarose gel used. The method employed here is simple and reproducible. As these materials have such large mesopore dimensions, they could be used as hard templates or could be specifically functionalized for use in environmental remediation, as environmentally responsive materials, biocatalysts, or catalysts.

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Polymer Gel Templating of Free-Standing Inorganic Monoliths for Photocatalysis

Cited by 20 publications

References 22 publications

Facile Preparation of Hierarchically Porous TiO₂ Monoliths

Facile Preparation of Hierarchically Porous TiO₂ Monoliths

Solid-state dye-sensitized solar cells from polymer-templated TiO₂ bilayer thin films

Strong Silica Monoliths with Large Mesopores Prepared Using Agarose Gel Templates

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Polymer Gel Templating of Free-Standing Inorganic Monoliths for Photocatalysis

Cited by 20 publications

References 22 publications

Facile Preparation of Hierarchically Porous TiO2 Monoliths

Facile Preparation of Hierarchically Porous TiO2 Monoliths

Solid-state dye-sensitized solar cells from polymer-templated TiO2 bilayer thin films

Strong Silica Monoliths with Large Mesopores Prepared Using Agarose Gel Templates

Contact Info

Product

Resources

About

Facile Preparation of Hierarchically Porous TiO₂ Monoliths

Facile Preparation of Hierarchically Porous TiO₂ Monoliths

Solid-state dye-sensitized solar cells from polymer-templated TiO₂ bilayer thin films