Protonic conductivity in hydrates

Barboux, P.

doi:10.1016/0167-2738(88)90213-5

Cited by 56 publications

(15 citation statements)

References 8 publications

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“…Below that limit there is an abrupt decrease of the amount of water in the compound, and above 80 % an additional amount of water is adsorbed. The conductivity is strongly dependent on the partial pressure of water (Figure 5b) and the shape of the curve is typical of a particle‐hydrate conductor 9. These results confirm that the conductivity is mainly due to surface‐proton motion.…”

Section: Resultssupporting

confidence: 67%

Octanuclear Oxothiomolybdate(V) Rings: Structure and Ionic‐Conducting Properties

Peloux

Dolbecq

Barboux

et al. 2004

Chemistry A European J

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A family of alkali salts of octanuclear oxothiomolybdate rings has been synthesized by crystallization of the [Mo(8)S(8)O(8)(OH)(8)[HMO(5)(H(2)O)]](3-) (noted HMo(8)M(3-); M=Mo, W) and [Mo(8)S(8)O(8)(OH)(8)(C(2)O(4))](2-) (noted Mo(8)ox(2-)) anions in an aqueous solution of ACl (A=Li, Na, K, Rb). Single-crystal X-ray diffraction experiments have been performed showing that the alkali salts exhibit a similar three-dimensional structure. Disordered alkali ions form columns to which the anionic rings are anchored. Ionic-conductivity measurements on pressed pellets have revealed two different behaviors. The lithium salts of HMo(8)M(3-) (M=Mo, W) are moderately good proton conductors at room temperature (sigma=10(-5) S cm(-1)) and the profile of conductivity as a function of relative humidity shows that the conductivity is due to surface-proton motion (particle-hydrate-type mechanism). On the other hand, the lithium salt of Mo(8)ox(2-) competes with the best crystalline lithium conductors at room temperature (sigma=10(-3) S cm(-1)), and (7)Li NMR experiments confirm the mobility of the lithium ions along the one-dimensional channels of this material.

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Section: Resultssupporting

confidence: 67%

Octanuclear Oxothiomolybdate(V) Rings: Structure and Ionic‐Conducting Properties

Peloux

Dolbecq

Barboux

et al. 2004

Chemistry A European J

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“…The crystallographic data and properties of cerium(III) phosphates – monazite ( P 2 1 / n ) and rhabdophane ( P 6 2 22) – have been thoroughly studied . Surprisingly, information on cerium(IV) phosphates is extremely scarce, despite their long history since the middle of the 20 th century and rich ceric coordination chemistry …”

Section: Introductionmentioning

confidence: 99%

Crystallization Pathways of Cerium(IV) Phosphates Under Hydrothermal Conditions: A Search for New Phases with a Tunnel Structure

et al. 2019

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“…The autoclave was mounted in a furnace, heated at a rate of 100°C/h to 235-245°C (6.0-7.0 MPa) and held at that temperature for 10-15 min. Next, the pressure in the heated autoclave was gradually lowered to atmospheric pressure and the autoclave was evacuated for min (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40), cooled and opened. Supercritical drying in CO 2 was carried out in a system that comprised a Supercritical high pressure pump for CO 2 (SSI, USA), a 50 mL steel reactor and a BPR back pressure regulator (Goregulator, Waters, USA).…”

Section: Methodsmentioning

confidence: 99%

“…The synthesis of rare-earth phosphate aerogels has not been reported, to date, although they may be of considerable interest, due to a number of valuable properties, including sorption [29], ion exchange [30], proton-conduction [31] and catalytic activities [32], which are typical, in particular, of cerium (IV) hydroorthophosphates. Despite the long history of cerium phosphates [33,34], cerium (III) orthophosphates of monazite or rhabdophane structures [35] remain the most investigated, whereas cerium (IV) orthophosphates have been studied to a much lesser degree.…”

Section: Introductionmentioning

confidence: 99%

First rare-earth phosphate aerogel: sol–gel synthesis of monolithic ceric hydrogen phosphate aerogel

Yorov

Шекунова

Baranchikov

et al. 2018

J Sol-Gel Sci Technol

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AnnotationSince the late 1960s, ceric hydrogen phosphates have attracted the attention of scientists due to remarkable ion exchange, sorption, proton-conduction and catalytic properties. In this work, through the application of various solvents, we, for the first time, have obtained monolithic aerogels based on ceric hydrogen phosphates with high porosity (~99%) and extremely low density (~10 g/cm 3 ). The composition and structure of aerogels were thoroughly studied with XRD, TEM, SEM, XPS, low temperature nitrogen adsorption methods, TGA/DSC, FTIR and SANS. The aerogels were found to belong to the fibrous macroporous aerogels family. IntroductionAerogels, being highly porous materials with low density and high specific surface area, are gels in which the liquid phase is completely replaced by a gaseous phase [1]. Aerogels are typically used as catalysts, sensors, ion-exchange materials, and as heat and sound insulators [2].They can be produced from a number of simple substances, both inorganic and organic compounds; hybrid organic-inorganic aerogels are also known [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].The most studied SiO 2 -based aerogels, obtained by hydrolysis of silicon alkoxides, with subsequent supercritical drying, consist of isotropic SiO 2 nanoparticles (0D) forming a spatial network [18]. Recently, a significant number of papers have also been published on the production of aerogels containing anisotropic 1D and 2D building blocks, including carbon nanotubes and graphene [19][20][21][22]. Special attention has been paid to monolithic materials having a similar architecture, but containing not only micropores (<2 nm) and mesopores (2-50 nm), but also macropores, since they have a highly accessible surface, which is guaranteed by macroporosity. In addition to the high permeability of such materials, which is important for their application as catalysts and sensors, they can be easily recovered for repetitive use [23].One of the most challenging tasks in the design of new multifunctional materials is the production of aerogels from orthophosphates of transition and rare-earth elements. Such materials could attract a great deal of interest, due to their extended applications in various possible applications, such as ion-exchange for water purification, catalysts, proton conductors, etc. At the same time, the data on the synthesis of such materials is extremely scarce. Thus, methods are reported for the synthesis of aerogels of the compositions Ti 3 (PO ) 4 [24]. Zhu et al. [23] described the synthesis of a monolithic aerogel based on zirconium phosphate, which can be used for the purification of water as a heavy metals sorbent.Studies concerning the preparation of surface-modified, phosphate-containing oxide aerogels have been also reported [25][26][27][28]. In particular, Boyse et al. [25] obtained Nb 2 O 5 -based aerogels containing 5 or 10 mol.% of niobium phosphate, which showed a high level of catalytic activity in the reaction of butene-1 isomerisation.The synthesis of rare-earth ph...

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Protonic conductivity in hydrates

Cited by 56 publications

References 8 publications

Octanuclear Oxothiomolybdate(V) Rings: Structure and Ionic‐Conducting Properties

Octanuclear Oxothiomolybdate(V) Rings: Structure and Ionic‐Conducting Properties

Crystallization Pathways of Cerium(IV) Phosphates Under Hydrothermal Conditions: A Search for New Phases with a Tunnel Structure

First rare-earth phosphate aerogel: sol–gel synthesis of monolithic ceric hydrogen phosphate aerogel

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