Preparation of porous solids composed of layered niobate walls from colloidal mixtures of niobate nanosheets and polystyrene spheres

Miyamoto, Nobuyoshi; Kuroda, Kazuyuki

doi:10.1016/j.jcis.2007.03.069

Cited by 16 publications

(11 citation statements)

References 29 publications

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“…1 The proton-exchanged hexaniobate has a fundamental participation in the production of nanosheets and nanoscrolls through exfoliation reactions [5] and, consequently, a significant importance to the development of new materials using the niobate anisotropic particles as nanobuilding blocks. The colloidal nanosheets can be assembled into nanostructured devices for photocurrent or photoluminescence generation [6], polymer nanocomposites [7], macroporous solids [8], catalysts for oxidation reaction [9], hybrids materials containing natural dyes [10] and systems for H 2 photo-production [11].…”

Section: Introductionmentioning

confidence: 99%

Intralamellar structural modifications related to the proton exchanging in K4Nb6O17 layered phase

Bizeto

Leroux

Shiguihara

et al. 2010

Journal of Physics and Chemistry of Solids

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Basic structural aspects about the layered hexaniobate of K 4 Nb 6 O 17 composition and its proton-exchanged form were investigated mainly by spectroscopic techniques. Raman spectra of hydrous K 4 Nb 6 O 17 and H 2 K 2 Nb 6 O 17 .H 2 O show significant modifications in the 950-800 cm -1 region (Nb-O stretching mode of highly distorted NbO 6 octahedra). The band at 900 cm -1 shifts to 940 cm -1 after the replacement of K + ion by proton. Raman spectra of the original materials and the related deuterated samples are similar suggesting that no isotopic effect occurs. Major modifications were observed when H 2 K 2 Nb 6 O 17 was dehydrated: the relative intensity of the band at 940 cm -1 decreases and new bands seems to be present at about 860-890 cm -1 . The H + ions should be shielded by the hydration sphere what preclude the interaction with the layers. Removing the water molecules, H + ions can establish a strong interaction with oxygen atoms, decreasing the bond order of Nb-O linkage. X-ray absorption near edge structure studies performed at Nb K-edge indicate that the niobium coordination number and oxidation state remain identical after the replacement of potassium by proton. From the refinement of the fine structure, it appears that the Nb-Nb coordination shell is divided into two main contributions of about 0.33 and 0.39 nm, and interestingly the population, i.e., the number of backscattering atoms is inversed between the two hexaniobate materials.

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Section: Introductionmentioning

confidence: 99%

Intralamellar structural modifications related to the proton exchanging in K4Nb6O17 layered phase

Bizeto

Leroux

Shiguihara

et al. 2010

Journal of Physics and Chemistry of Solids

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“…14 Chemical modification of niobate by the intercalation route is mainly driven by the fact that the pre-intercalation with polyether monoamine surfactant, 15 tetraalkylammonium ion (from tetrabutylammonium hydroxide solutions), 16 and n-alkylammonium ion 17 promotes the exfoliation of layered niobate. This process produces a colloidal dispersion of inorganic nanosheets, suitable for preparation of thin films to generate photocurrent using [Ru(bpy) 3 ] 2+ sensitizer, 18 photoluminescence from rare earth ions, 19 molecular hydrogen from water under illumination, 20 protonic conductor, 21 Li + conductor, 22 interstratified materials with layered double hydroxides, 23 acid catalysts, 24 macroporous niobate, 25 biosensors based on hemoglobin 26 and other materials, as reviewed recently. 27 In addition, niobate nanosheets in colloidal dispersion can undergo a curling process forming tubular or scrolled inorganic nanoparticles under soft chemical conditions.…”

Section: Introductionmentioning

confidence: 99%

Chemical modification of niobium layered oxide by tetraalkylammonium intercalation

Shiguihara¹,

Bizeto²,

Constantino³

2010

J. Braz. Chem. Soc.

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. Aquecendo-se as amostras acima de 200-250 o C, observa-se a liberação de CO 2 ; a reação de eliminação de Hofmann também é observada para as amostras de hexaniobato-tpa + . As imagens de microscopia eletrônica de varredura mostram a presença predominante de partículas em forma de placas; partículas em forma de bastões também são observadas nas amostras contendo íons volumosos. A reação de intercalação é promovida na ordem tma + > tea + > tpa + , enquanto a formação de uma dispersão de partículas coloidais é facilitada na ordem inversa.Chemical modification of the layered K 4 Nb 6 O 17 material was systematically investigated through the reaction of its proton-exchanged form (H 2 K 2 Nb 6 O 17 ) in alkaline solutions containing tetramethylammonium (tma + ), tetraethylammonium (tea + ) or tetrapropylammonium (tpa + ) cations. The intercalated amount reaches 50% (for tma C, CO 2 evolution is observed; Hofmann elimination reaction is also detected for hexaniobate-tpa + samples. Scanning electron microscopy images show the predominance of plate-like particles; stick-like particles are also observed for samples containing bulky ions. The intercalation reaction is promoted in the order tma + > tea + > tpa + , while the formation of a dispersion of colloidal particles is facilitated in the inverse order. Keywords: layered niobate, hexaniobate, tetraalkylammonium, intercalation IntroductionNew materials have been prepared combining chemical species that show unlike properties such as organic, inorganic and biochemicals in order to develop systems with improved or unique performance. However, the design of these hybrid materials requires chemical strategies to compatibilize so dissimilar species at the nanoscopic domain. One plausible approach demands the use of chemical reactions or processes that enhance the physicochemical interactions among the counterparts.Considering inorganic phases, suitable reactions to increase the interaction with organic species consist in (i) functionalization of the inorganic surfaces through covalent bonds with appropriated pendent groups or (ii) ion exchange of charged species that neutralize inorganic surfaces by proper ions.1 Chemical modification of inorganic nanostructures or nanocrystals has deserved special attention in the recent literature.1,2 Organicinorganic and biochemical-inorganic hybrid materials can be explored in diversified studies concerning the Shiguihara et al. 1367 Vol. 21, No. 7, 2010 preparation of nanostructured thin-films, macro-or mesoporous solids, biomaterials, biosensors, polymer nanocomposites, catalysts and photocatalysts, devices for generation of photocurrent or photoluminescence, and hierarchical structures. 1,2Among the inorganic materials, the layered frameworks can produce nanostructured hybrid materials by intercalation of guest species between the layers or reassemblage of the anisotropic nanosheets produced in an exfoliation process. Layered niobates are an important class of inorganic materials that have some interesting characteristics such as...

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“…Miyamoto et al also reported the synthesis of macroporous solids with a variety of structures from colloidal mixtures of PS spheres and inorganic nanosheets. 272 The relative size differences between the spheres and the nanosheets strongly affected the structure.…”

Section: Hard-templatesmentioning

confidence: 99%

Templated Synthesis for Nanoarchitectured Porous Materials

Malgras

Kamachi

et al. 2015

Bulletin of the Chemical Society of Japan

520

233

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Preparation of porous solids composed of layered niobate walls from colloidal mixtures of niobate nanosheets and polystyrene spheres

Cited by 16 publications

References 29 publications

Intralamellar structural modifications related to the proton exchanging in K4Nb6O17 layered phase

Intralamellar structural modifications related to the proton exchanging in K4Nb6O17 layered phase

Chemical modification of niobium layered oxide by tetraalkylammonium intercalation

Templated Synthesis for Nanoarchitectured Porous Materials

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