scholarly journals Structural variability in M2+ 2-hydroxyphosphonoacetate moderate proton conductors

2017 ◽  
Vol 89 (1) ◽  
pp. 75-87 ◽  
Author(s):  
Rosario M. P. Colodrero ◽  
Inés R. Salcedo ◽  
Montse Bazaga-García ◽  
Diego F. Milla-Pérez ◽  
Jonatan D. Durán-Martín ◽  
...  
Keyword(s):  
Proton Conductivity ◽  
State Transition ◽  
Proton Conductors ◽  
Water Molecules ◽  
Ammonia Adsorption ◽  
X Ray ◽  
Structural Variability ◽  
Solid State Transition ◽  
2D And 3D ◽  
3D Framework

Abstract The structural variability of two series of Mg2+- and Zn2+- 2-hydroxyphosphonoacetates have been studied in the range of 25–80°C and 95% relative humidity in order to correlate the structure with the proton conductivity properties. In addition to selected previously reported 1D, 2D and 3D materials, a new compound, KZn6(OOCCH(OH)PO3)4(OH)·5H2O (KZn6-HPAA-3D), has been prepared and thoroughly characterized. The crystal structure of this solid, solved ab initio from synchrotron X-ray powder diffraction data, consists of a negatively charged 3D framework with K+ ions, as compensating counterions. It also contains water molecules filling the cavities in contrast to the potassium-free 3D anhydrous NH4Zn(OOCCH(OH)PO3) (NH4Zn-HPAA-3D). In the range of temperature studied, the 1D materials exhibit a 1D→2D solid-state transition. At 80°C and 95% RH, the 2D solids show moderate proton conductivities, between 2.1×10−5 S·cm−1 and 6.7×10−5 S·cm−1. The proton conductivity is slightly increased by ammonia adsorption up to 2.6×10−4 S·cm−1, although no ammonia intercalation was observed. As synthesized KZn6-HPAA-3D exhibits a low proton conductivity, 1.6×10−6 S·cm−1, attributed to the basic character of the framework and a low mobility of water molecules. However, this solid transforms to the 2D phase, Zn(OOCCH(OH)PO3H)·2H2O, upon exposure to dry HCl(g), which enhances the proton conductivity with respect to the as-synthesized 2D material (4.5×10−4 S·cm−1). On the other hand, NH4Zn-HPAA-3D exhibited a higher proton conductivity, 1.4×10−4 S·cm−1, than the K+ analog.

Electrochemical hydrogen production from humid air using cation-modified graphene oxide membranes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nur Laila Hamidah ◽  
Masataka Shintani ◽  
Aynul Sakinah Ahmad Fauzi ◽  
Shota Kitamura ◽  
Elaine G. Mission ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Proton Conductivity ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Water Electrolysis ◽  
Proton Conductors ◽  
X Ray ◽  
Chemical Structures ◽  
Modified Graphene Oxide ◽  
Modified Graphene

AbstractWater electrolysis is an environment-friendly process of producing hydrogen with zero-carbon emission. Herein, we studied the water vapor electrolysis using a proton-conducting membrane composed of graphene oxide (GO) nanosheets intercalated with cations (Al3+ and Ce3+). We examined the effect of cation introduction on the physical and chemical structures, morphology, thermal and chemical stabilities, and the proton conductivity of stacked GO nanosheet membranes by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoemission spectroscopy (XPS), Raman spectroscopy, atomic force microscopy (AFM), dynamic light scattering (DLS), thermogravimetric-differential thermal analysis (TG-DTA), and electrochemical impedance spectroscopy (EIS). Concentration cell measurements revealed that the cation-modified membranes are pure proton conductors at room temperature. The proton conductivity of a GO membrane was much improved by cation modification. The cation-modified GO membranes, sandwiched with Pt/C electrodes as the cathode and anode, electrolyzed humidified air to produce hydrogen at room temperature, indicating the feasibility of this carbon-based electrochemical device.

scholarly journals Crystal Structure and Electrochemical Property of Tetrazole Complex of Copper [Cu(pta)2(NO3)2(H2O)2] (pta = 1-Phenyl-1H-tetrazole)

2019 ◽  
Vol 31 (10) ◽  
pp. 2370-2374
Author(s):  
E. Liu ◽  
Fangfang Jian
Keyword(s):  
Crystal Structure ◽  
Irreversible Process ◽  
Membered Ring ◽  
Water Molecules ◽  
Stacking Interactions ◽  
Coordination Geometry ◽  
X Ray ◽  
Electrode Cell ◽  
2D Network ◽  
3D Framework

A new compound, [Cu(pta)2(NO3)2(H2O)2] (pta = 1-phenyl-1H-tetrazole) has been synthesized and characterized by IR, elemental analysis and single-crystal X-ray diffractions. X-ray structural analysis reveals that each Cu atom is coordinated by two pta molecules, two nitrate ions and two water molecules to form octahedral coordination geometry. O(1w) atoms of the water molecules serve as H-donor to interact with the nitrate oxygen atoms O(2), O(3) (H-acceptor) and form 1D hydrogen-bond ladder chains. These chains then, construct a 2D network layer via π-π stacking interactions between the five-membered ring of tetrazole and the six-membered ring of benzene. The 3D framework was constructed through the hydrogen bonds of C(7)-H(7A)····O(3). The behaviour of cyclic voltammetry of the compound on three-electrode cell showed an irreversible process.

Chain caesium borophosphates with B:P ratio 1:2: synthesis, structure relationships and low-temperature thermodynamic properties

2019 ◽  
Vol 75 (6) ◽  
pp. 1174-1185
Author(s):  
Larisa Shvanskaya ◽  
Olga Yakubovich ◽  
Polina Krikunova ◽  
Evgeny Ovchenkov ◽  
Alexander Vasiliev
Keyword(s):  
Magnetic Field ◽  
Hydrogen Bond ◽  
Thermodynamic Properties ◽  
Membered Ring ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Common Edge ◽  
X Ray ◽  
Hydrogen Bond Interactions ◽  
3D Framework

Three caesium-bearing borophosphates, Cs[BP2O6(OH)2] (I), Cs0.51Mn1.17(H2O)2[BP2O8]·0.45H2O (II) and CsMn[BP2O8(OH)] (III), were synthesized by a hydrothermal method at 473–523 K. Their crystal structures have been studied by means of single-crystal X-ray diffraction; all three structures comprise borophosphate chain anions with a B:P ratio of 1:2. The unique construction of (I) is based on four-membered-ring chains running parallel to the [010] direction. These protonated borophosphate chains are linked via hydrogen-bond interactions to form a 3D framework with caesium cations incorporated. (II) is the first Cs and Mn2+,Mn3+ member of a known family characterized by [BP2O8]∞ helical chains running along [001]. These chains are connected through MnO4(H2O)2 octahedra to form a 3D framework. The caesium cations are disordered over two independent positions in the channels, which they occupy together with water molecules. An additional MnO2(H2O)3 bipyramid statistically shares a common edge and two corners with three main Mn octahedra to form tetrameric clusters. The topological relation between the chain anionic fragments of (I) and (II) as well as the structural relation between (I) and previously studied boro- and berillophosphates are discussed. Compound (III) presents the first Mn member of the A I M III[BP2O8(OH)] family and is characterized by a 3D framework built by open-branched borophosphate chains and MnO5 semi-octahedra sharing vertices. The measurements of thermodynamic properties, i.e. magnetization M and specific heat C p, to 2 K and 30 T, provide evidence that (II) orders antiferromagnetically at the Néel temperature T N = 4.6 K and exhibits a plateau-like feature under the action of an external magnetic field accompanied by a pronounced magnetocaloric effect.

Structural Study of a new Compound Based on Acid 1,4-Cyclohexanedicarboxylic (1,4-CDC)

2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari
Keyword(s):  
Aqueous Solution ◽  
Water Molecules ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Compound I ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Cyclohexanedicarboxylic Acid

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.

High proton conductivity in a nickel(ii) complex and its hybrid membrane

2019 ◽  
Vol 48 (6) ◽  
pp. 2190-2196 ◽  
Author(s):  
Shuai-Liang Yang ◽  
Yue-Ying Yuan ◽  
Fei Ren ◽  
Chen-Xi Zhang ◽  
Qing-Lun Wang
Keyword(s):  
Hydrogen Bond ◽  
Proton Conductivity ◽  
Hybrid Membrane ◽  
Water Molecules ◽  
Hybrid Membranes ◽  
High Proton Conductivity ◽  
High Proton ◽  
Hydrogen Bond Networks

A novel 2D nickel(ii) complex (1) has been successfully synthesized using a 2,2′-bipyridyl, polycarboxylsulfonate ligand H4SBTC and Ni2+ ions. Owing to the presence of abundant water molecules, hydrogen bond networks and other protons, 1 and its hybrid membranes demonstrate high proton conductivity.

scholarly journals X-ray diffraction analysis of matter taking into account the second harmonic in the scattering of powerful ultrashort pulses of an electromagnetic field

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. K. Eseev ◽  
A. A. Goshev ◽  
K. A. Makarova ◽  
D. N. Makarov
Keyword(s):  
Electromagnetic Field ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Second Harmonic ◽  
Ultrashort Pulses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scattering Spectra ◽  
Technical Possibility ◽  
2D And 3D

AbstractIt is well known that the scattering of ultrashort pulses (USPs) of an electromagnetic field in the X-ray frequency range can be used in diffraction analysis. When such USPs are scattered by various polyatomic objects, a diffraction pattern appears from which the structure of the object can be determined. Today, there is a technical possibility of creating powerful USP sources and the analysis of the scattering spectra of such pulses is a high-precision instrument for studying the structure of matter. As a rule, such scattering occurs at a frequency close to the carrier frequency of the incident USP. In this work, it is shown that for high-power USPs, where the magnetic component of USPs cannot be neglected, scattering at the second harmonic appears. The scattering of USPs by the second harmonic has a characteristic diffraction pattern which can be used to judge the structure of the scattering object; combining the scattering spectra at the first and second harmonics therefore greatly enhances the diffraction analysis of matter. Scattering spectra at the first and second harmonics are shown for various polyatomic objects: examples considered are 2D and 3D materials such as graphene, carbon nanotubes, and hybrid structures consisting of nanotubes. The theory developed in this work can be applied to various multivolume objects and is quite simple for X-ray structural analysis, because it is based on analytical expressions.

scholarly journals Structure of aqueous sodium acetate solutions by X-Ray scattering and density functional theory

2020 ◽  
Vol 92 (10) ◽  
pp. 1627-1641
Author(s):  
Guangguo Wang ◽  
Yongquan Zhou ◽  
He Lin ◽  
Zhuanfang Jing ◽  
Hongyan Liu ◽  
...  
Keyword(s):  
Sodium Acetate ◽  
Density Functional ◽  
Hydration Shell ◽  
Ion Pair ◽  
Water Molecules ◽  
Sodium Acetate Solution ◽  
Acetate Solution ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

AbstractThe structure of aq. sodium acetate solution (CH3COONa, NaOAc) was studied by X-ray scattering and density function theory (DFT). For the first hydrated layer of Na+, coordination number (CN) between Na+ and O(W, I) decreases from 5.02 ± 0.85 at 0.976 mol/L to 3.62 ± 1.21 at 4.453 mol/L. The hydration of carbonyl oxygen (OC) and hydroxyl oxygen (OOC) of CH3COO− were investigated separately and the OC shows a stronger hydration bonds comparing with OOC. With concentrations increasing, the hydration shell structures of CH3COO− are not affected by the presence of large number of ions, each CH3COO− group binds about 6.23 ± 2.01 to 7.35 ± 1.73 water molecules, which indicates a relatively strong interaction between CH3COO− and water molecules. The larger uncertainty of the CN of Na+ and OC(OOC) reflects the relative looseness of Na-OC and Na-OOC ion pairs in aq. NaOAc solutions, even at the highest concentration (4.453 mol/L), suggesting the lack of contact ion pair (CIP) formation. In aq. NaOAc solutions, the so called “structure breaking” property of Na+ and CH3COO− become effective only for the second hydration sphere of bulk water. The DFT calculations of CH3COONa (H2O)n=5–7 clusters suggest that the solvent-shared ion pair (SIP) structures appear at n = 6 and become dominant at n = 7, which is well consistent with the result from X-ray scattering.

Fast Proton Conductors from Inorganic-Organic Composites: I. Amorphous Phosphate-Nafion and Silicophosphate-PMA/PWA Hybrids

1999 ◽  
Vol 600 ◽  
Author(s):  
Yong-Il Park ◽  
Jae-Dong Kim ◽  
Masayuki Nagai
Keyword(s):  
Phosphoric Acid ◽  
Proton Conductivity ◽  
Proton Conductors ◽  
Phosphorus Concentration ◽  
High Proton ◽  
Proton Source ◽  
Drastic Increase ◽  
Amorphous Phosphate ◽  
Exchange Resins ◽  
Very High

AbstractA drastic increase of electrical conductivity was observed in the composite of amorphous phosphate and ion-exchange resins (Nafion) as phosphorus concentration increased. Incorporation of amorphous phosphate into Nafion caused a large increase of conductivity to about 4×10−1S/cm at 23°C. However, the fabricated composite showed very low chemical stability.A high proton conductivity was also observed in a new inorganic-organic hybrids through incorporating PMA(molibdo-phosphoric acid)/PWA(tungsto-phosphoric acid) as a proton source in amorphous silicophosphate gel structure. Obtained gels were homogeneous and chemically stable. Resulting proton conductivity is very high (up to 5.5×10−3S/cm) compared to those of silicophosphate gels.

scholarly journals Rb1.66Cs1.34Tb[Si5.43Ge0.57O15]·H2O, a New Member of the OD-Family of Natural and Synthetic Layered Silicates: Topology-Symmetry Analysis and Structure Prediction

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 395
Author(s):  
Anastasiia Topnikova ◽  
Elena Belokoneva ◽  
Olga Dimitrova ◽  
Anatoly Volkov ◽  
Dina Deyneko
Keyword(s):  
Structure Prediction ◽  
Symmetry Analysis ◽  
Layered Silicates ◽  
Water Molecules ◽  
Structural Variants ◽  
X Ray ◽  
A Chain ◽  
Multi Component System ◽  
Tetrahedral Layer ◽  
Natural And Synthetic

Crystals of new silicate-germanate Rb1.66Cs1.34Tb[Si5.43Ge0.57O15]·H2O have been synthesized hydrothermally in a multi-component system TbCl3:GeO2:SiO2 = 1:1:5 at T = 280 °C and P = 100 atm. K2CO3, Rb2CO3 and Cs2CO3 were added to the solution as mineralizers. The crystal structure was solved using single crystal X-ray data: a = 15.9429(3), b = 14.8407(3), c = 7.2781(1) Å, sp. gr. Pbam. New Rb,Cs,Tb-silicate-germanate consists of a [Si5.43Ge0.57O15]∞∞ corrugated tetrahedral layer combined by isolated TbO6 octahedra into the mixed microporous framework as in synthetic K3Nd[Si6O15]·2H2O, K3Nd[Si6O15] and K3Eu[Si6O15]·2H2O with the cavities occupied by Cs, Rb atoms and water molecules. Luminescence spectrum on new crystals was obtained and analysed. A comparison with the other representatives of related layered natural and synthetic silicates was carried out based on the topology-symmetry analysis by the OD (order-disorder) approach. The wollastonite chain was selected as the initial structural unit. Three symmetrical ways of forming ribbon from such a chain and three ways of further connecting ribbons to each other into the layer were revealed and described with symmetry groupoids. Hypothetical structural variants of the layers and ribbons in this family were predicted.

Sign in / Sign up

Export Citation Format

Share Document