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

Bizeto, Marcos A.; Leroux, Fabrice; Shiguihara, Ana Lucia; Temperini, Márcia L. A.; Sala, O.; Constantino, Vera Regina Leopoldo

doi:10.1016/j.jpcs.2009.12.036

Cited by 31 publications

(21 citation statements)

References 22 publications

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“…33 Replacement of K + by protons increases the bond order of the short and terminal Nb-O bonds because H + ions are probably shielded by the hydration sphere, precluding interaction with the layers. 48 As can be seen in Figure 6, the partial substitution of protons by tma + provokes the appearance of a new band at about 900 cm -1 , suggesting an increase in the Nb=O bond order. The shoulder at about 940 cm -1 in the spectrum of tma(1.0)dep can be attributed to the antisymmetric stretching vibration of the C 4 N + group.…”

Section: Resultsmentioning

confidence: 80%

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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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Section: Resultsmentioning

confidence: 80%

“…48 As can be seen in Figure 6, the partial substitution of protons by tma + provokes the appearance of a new band at about 900 cm -1 , suggesting an increase in the Nb=O bond order. The shoulder at about 940 cm -1 in the spectrum of tma(1.0)dep can be attributed to the antisymmetric stretching vibration of the C 4 N + group.…”

mentioning

confidence: 80%

Chemical modification of niobium layered oxide by tetraalkylammonium intercalation

Shiguihara¹,

Bizeto²,

Constantino³

2010

J. Braz. Chem. Soc.

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“…The peaks located at around 3.0 Å reflect the NbNb bonds. [ 29 ] The bond lengths and related coordination numbers are acquired by using linear combination fitting, as displayed in Figure S10 and Table S2 (Supporting Information). The low R factors (around 2%) confirm the quality of the fitting.…”

Section: Methodsmentioning

confidence: 99%

Dehydration‐Triggered Ionic Channel Engineering in Potassium Niobate for Li/K‐Ion Storage

et al. 2020

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physicochemical behaviors, [1][2][3] in several ways that are particularly desirable for electrochemical ions storage relying on reversible ionic (de)intercalation of metal ions, such as Li + , [4] Na + , [5] Mg 2+ , [6] Zn 2+ , [7] etc. In the ionic batteries, this involves the shuttling and storage of ions between two electrodes, coupled with the flow of electrons in an external circuit. Therefore, efficiently delivering sufficient numbers of ions through ionic channels in the electrode is the main factor needed to achieve elevated energy density under a high current rate. [8] To address the charge transport limitations of electrodes, constructing interconnected ionic channels can offer highly efficient charge delivery. [9] Meanwhile, the introduction of tailoring materials at the atomic level is more effective and does not require sacrificing the energy density of the electrode. [10,11] Recently, studies have reported the inner channel for ionic transport in materials and the external ionic diffusion from the electrolyte to the channels are two main factors influencing the ionic kinetics. [12] Regulating the channels in the electrodes will promote the mobility and diffusion kinetics of exotic ions. [13] For example, graphite, the commercialized anode for lithium-ion batteries (LIBs), has shown an inferior capacity when being utilized for sodium ion batteries due to the insufficient interlayer spacing and unaffordable energy barrier for intercalation/extraction of Na + ions. [14] In contrast, expanded graphite with a wider atomic interlayer spacing shows improved capability for Na + storage. [15] A "blended cocktail strategy" with precise control and construction of high electronic conductivity and interconnected ionic channels may hold the key to optimizing the energy performance of batteries. Currently, most of the primary investigation of other types of metal ion batteries have investigated replacements from previously successful electrodes in LIBs, including carbonaceous materials, [16,17] alloy-based compounds, [18] and sulfides. [19] Interestingly, a recent work reported that niobium-based electrode materials possessing fascinating properties, such as an intercalation-type mechanism, rich redox chemistry, and achievable scalability at a practical level, have been identified as ideal candidates for rechargeable metal ion batteries. [20] Moreover, a higher working voltage Boosting charge transfer in materials is critical for applications involving charge carriers. Engineering ionic channels in electrode materials can create a skeleton to manipulate their ion and electron behaviors with favorable parameters to promote their capacity and stability. Here, tailoring of the atomic structure in layered potassium niobate (K 4 Nb 6 O 17 ) nanosheets and facilitating their application in lithium and potassium storage by dehydration-triggered lattice rearrangement is reported. The spectroscopy results reveal that the interatomic distances of the NbO coordination in the engineered K 4 Nb 6 O 17 are slightly elongated...

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“…The KN4617 crystal has an orthorhombic structure of which, its lattice parameters are a = 0.7816, b = 3.312 and c = 0.6480 nm, and with a space group of P2 1 nb (33) [47]. There is a disadvantage with the KN4617 crystal; it is easy to absorb moisture (hydrated) to become K 4 Nb 6 O 17 -H 2 O [49,50]. The KN4617 crystal was reported as a ferroelectric nonlinear material, but its electric properties have not been subjected to much study so far.…”

Section: The Effects Of K 4 Nb 6 O 17 On Knbomentioning

confidence: 99%

Potential Advantage of Multiple Alkali Metal Doped KNbO3 Single Crystals

et al. 2014

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Potassium niobate crystal KNbO 3 (KN) is a well-known crystal for lead free piezoelectric or nonlinear optical applications. The KN crystal has been studied in both single crystal form and in thin film form which has resulted in many review articles being published. In order to exceed the KN crystal, it is important to study KN phase forming and doping effects on the K site. This article summarizes the authors' study towards a multiple alkali metal doped KN crystal and related single crystals briefly from the viewpoint of crystal growth.

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

Cited by 31 publications

References 22 publications

Chemical modification of niobium layered oxide by tetraalkylammonium intercalation

Chemical modification of niobium layered oxide by tetraalkylammonium intercalation

Dehydration‐Triggered Ionic Channel Engineering in Potassium Niobate for Li/K‐Ion Storage

Potential Advantage of Multiple Alkali Metal Doped KNbO3 Single Crystals

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