Silica–alumina/sepiolite nanoarchitectures

Belver, Carolina; Ruiz-Hitzky, Eduardo

doi:10.1039/c3ta01686b

Cited by 34 publications

(15 citation statements)

References 52 publications

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“…6). Comparable behavior has been also reported for diverse heterostructured materials based on sepiolite, where organic or inorganic components can partially penetrate the sepiolite structural tunnels impeding the silicate folding [18,24]. …”

Section: Resultsmentioning

confidence: 78%

“…The disappearance of this band is attributed to the direct interaction of silanol groups with the diverse species located at the sepiolite surface in each case. Proof of this is the fact that the ν O–H stretching vibration band ascribed to Mg-OH groups appearing at 3680 cm −1 remains unaltered in all the spectra, which was expected as they are located at the interior of the structural blocks of sepiolite without access to the adsorbed species on the silicate [18,24]. …”

Section: Resultsmentioning

confidence: 99%

“…In general, this sol–gel procedure leads to heterostructured clay-based materials with enhanced textural properties compared to the ones of pristine silicates [14]. The simultaneous use of silicon and metal-alkoxide precursors gives rise, for instance, to the formation of silica/alumina-clay heterostructures providing acid-catalyst behavior [18–19]. Similarly, silica–titania delaminated clays have been also prepared via the generation of TiO 2 /SiO 2 NP in the interlayer space of smectites and vermiculites modified with long-chain alkylammonium species, promoting a clay delamination that leads to new porous TiO 2 /SiO 2 -layered clay heterostructures [20].…”

Section: Introductionmentioning

confidence: 99%

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Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

Akkari¹,

Amara²,

Ruiz‐Hitzky³

2016

Beilstein J. Nanotechnol.

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In this study, ZnO/SiO2-clay heterostructures were successfully synthesized by a facile two-step process applied to two types of clays: montmorillonite layered silicate and sepiolite microfibrous clay mineral. In the first step, intermediate silica–organoclay hybrid heterostructures were prepared following a colloidal route based on the controlled hydrolysis of tetramethoxysilane in the presence of the starting organoclay. Later on, pre-formed ZnO nanoparticles (NP) dispersed in 2-propanol were incorporated under ultrasound irradiation to the silica–organoclay hybrid heterostructures dispersed in 2-propanol, and finally, the resulting solids were calcinated to eliminate the organic matter and to produce ZnO nanoparticles (NP) homogeneously assembled to the clay–SiO2 framework. In the case of montmorillonite the resulting materials were identified as delaminated clays of ZnO/SiO2-clay composition, whereas for sepiolite, the resulting heterostructure is constituted by the assembling of ZnO NP to the sepiolite–silica substrate only affecting the external surface of the clay. The structural and morphological features of the prepared heterostructures were characterized by diverse physico-chemical techniques (such as XRD, FTIR, TEM, FE-SEM). The efficiency of these new porous ZnO/SiO2-clay heterostructures as potential photocatalysts in the degradation of organic dyes and the removal of pharmaceutical drugs in water solution was tested using methylene blue and ibuprofen compounds, respectively, as model of pollutants.

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

Akkari¹,

Amara²,

Ruiz‐Hitzky³

2016

Beilstein J. Nanotechnol.

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“…In the case of clay minerals with poorer‐crystallinity (sheet average up to 50 nm) (Figure B), the stacking of the sheets is worse defined so the cationic exchange generates mutual edge‐to‐edge and edge‐to face interactions, obtaining an individual piling of lamellae anchored by the growth of the silicate network in a three‐dimensional structure ,. Several authors have synthesized nanocomposites using fibrous silicates, such as sepiolite or paligorskite . The clay minerals hardly have cations in the interlayer space by the inversion of the tetrahedral sheet so the adsorption of the surfactant takes place on the surface.…”

Section: Porous Clay Heterostructuresmentioning

confidence: 99%

Synthesis, Characterization, Uses and Applications of Porous Clays Heterostructures: A Review

Cecilia

García‐Sancho

Vilarrasa-García

et al. 2018

The Chemical Record

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Porous clay heterostructures (PCH) are obtained by the insertion of an organic bulky cation in the interlayer spacing of a smectite, causing a swelling of the clay mineral. Right after, oxides species, mainly silicon oxide, are incorporated as pillars galleries between adjacent layers to form a porous structure after the removal of the template. The ordering of the clay mineral as well the organic cation incorporated in the synthetic step favors the modulation of the textural properties of the PCH. In addition, the incorporation of heteroatoms in the pillars galleries can also modulate the acidity of the PCH. The modulation of the pore size and the acid properties provides to these materials a wide range of applications in the fields of adsorption and catalysis. This paper carries out a detailed review of the synthesis of PCH, characterization as well as uses and application reported in the literature.

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“…We have also proved that it is possible to use commercial organosepiolites as intermediates, as reported in the paper by Belver and coworkers dealing with the preparation of diverse SiO 2 −Al 2 O 3 /sepiolite nanoarchitectures from Pangel B40, an organoclay commercialized by TOLSA SA as organophilic product. This study also showed how the versatility of the sol‐gel method permits to combine the alkoxide precursors in diverse ratio to produce NP with diverse chemical composition that in this case allows tuning textural and acid properties of the final materials, which affect their activity as catalysts in the dehydration of alcohols to olefins …”

Section: In Situ Generation Of Np In Presence Of Sepiolitementioning

confidence: 99%

Immobilization of Nanoparticles on Fibrous Clay Surfaces: Towards Promising Nanoplatforms for Advanced Functional Applications

Aranda

Ruiz‐Hitzky

2018

The Chemical Record

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This account discusses on diverse general approaches employed for the preparation of heterostructured materials based on the immobilization of metal oxides and other nanoparticles on sepiolite and palygorskite fibrous clay minerals, showing the many opportunities of application offered by the resulting materials. Various examples from our own experience have been selected to show how sepiolite acts as a convenient nanoplatform for immobilization of diverse type of nanoparticles, such as TiO , Fe O , Prussian blue, zeolites, layered double hydroxides, carbon nanotubes and graphenes, etc., to produce functional materials for applications in catalysis, environmental remediation, sensing devices, energy production, and others.

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Silica–alumina/sepiolite nanoarchitectures

Cited by 34 publications

References 52 publications

Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

Organoclay hybrid materials as precursors of porous ZnO/silica-clay heterostructures for photocatalytic applications

Synthesis, Characterization, Uses and Applications of Porous Clays Heterostructures: A Review

Immobilization of Nanoparticles on Fibrous Clay Surfaces: Towards Promising Nanoplatforms for Advanced Functional Applications

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