scholarly journals Water in Sugar Electrolytes and Application to Electrodeposition of Superconducting Rhenium

2022 ◽  
Author(s):  
Qiang Huang
Keyword(s):  
Limiting Current ◽  
Crystallographic Structure ◽  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
Rotating Disc ◽  
X Ray ◽  
Stationary Electrode ◽  
Diffusion Rates ◽  
Disc Electrodes ◽  
Rotating Electrodes

Abstract A systematic electrochemical study is carried out on electrolytes with superhigh concentrations of fructose. The effect of fructose concentration on the viscosity and conductivity of electrolyte are determined and analyzed using Walden rule and the theory of rate process. The diffusion rates of proton and cupric cation are calculated from the peak current in cyclic voltammogram on stationary electrode and the limiting current on rotating electrodes. Raman spectroscopy is used to characterize the hydrogen bond network in water and the effect of fructose concentration on such network. Rhenium deposition with different fructose concentrations is studied on rotating disc electrodes. X-ray fluorescence, X-ray diffraction, and four point probe measurements at cryogenic temperature are used to study the deposition rate, crystallographic structure, and superconductivity of film, respectively.

Eine elektrochemische und strukturelle Studie an den Eisensilylamiden Fe[N(SiMe3)2]2 und Fe[N(SiMe3)2]3 / An Electrochemical and Structural Study of the Iron Silylamides Fe[N(SiMe3)2]2 and Fe[N(SiMe3)2]3

2012 ◽  
Vol 67 (6) ◽  
pp. 549-556 ◽  
Author(s):  
Günter Margraf ◽  
Frauke Schödel ◽  
Inge Sänger ◽  
Michael Bolte ◽  
Matthias Wagner ◽  
...  
Keyword(s):  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
Amido Complexes ◽  
X Ray ◽  
Redox Transition ◽  
Transfer Processes ◽  
Irreversible Oxidation ◽  
Reaction Solution ◽  
Reversible Redox ◽  
Electron Transfer Processes

The bis(trimethyl)silylamido complex Na(THF){Fe[N(SiMe3)2]3} and the disilane tBu3SiSitBu3 were obtained from the reaction of Fe[N(SiMe3)2]3 with the sodium silanide Na(THF)2[SitBu3] in a mixture of benzene and THF. Single crystals of Na(THF){Fe[N(SiMe3)2]3} suitable for X-ray diffraction were grown from the reaction solution at ambient temperature (orthorhombic, C2221, Z = 4). The solid-state structure features a contact-ion pair with two short N-Na contacts. The THF adducts {M(THF)2[N(SiMe3)2]2} reacted with 2,2´-bipyridine to give the corresponding complexes {M(2,2´bipy)[N(SiMe3)2]2} (M= Mn; Fe). Their structures (M= Fe: orthorhombic, Pca21, Z = 8; M = Mn: orthorhombic, Pbca, Z = 8) feature monomeric units. The cyclic voltammogram of Fe[N(SiMe3)2]3 revealed a reversible redox transition with the potential of -0;523 V (E½), which was assigned to the Fe(III)[N(SiMe3)2]3 → Fe(II)[N(SiMe3)2]-3 redox transition, whereas the compounds {Fe(THF)2[N(SiMe3)2]2} (Eox = -0;379 V) and {Fe(2,2´bipy)[N(SiMe3)2]2} (Eox = -0;436 V) featured irreversible oxidation waves. The related manganese bis(trimethylsilyl)amido complexes {Mn(THF)2[N(SiMe3)2]2} (Eox = -0;458 V) and {Mn(2,2´bipy)[N(SiMe3)2]2} (Eox = -0513 V) also underwent irreversibile electron transfer processes.

scholarly journals Influence of Nanocrystalline Palladium Morphology on Alkaline Oxygen Reduction Kinetics

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 566 ◽  
Author(s):  
Eliran Hamo ◽  
Avichay Raviv ◽  
Brian A. Rosen
Keyword(s):  
Oxygen Reduction ◽  
High Surface ◽  
Reduction Reaction ◽  
Membrane Electrode ◽  
X Ray Diffraction ◽  
Rotating Disc ◽  
Force Microscopy ◽  
Atomic Force ◽  
Orr Kinetics ◽  
Disc Electrodes

The structure sensitivity of the alkaline oxygen reduction reaction (ORR) on palladium is of great interest as cost considerations drive the need to find a replacement for platinum catalysts. The kinetics of alkaline ORR were investigated on nanocrystalline palladium (Pd) films with domain sizes between 14 and 30 nm that were synthesized by electrodeposition from aqueous electrolytes. Ten Pd films were prepared under varying electrodeposition parameters leading to each having a unique texture and morphology. The sensitivity of initial alkaline ORR kinetics to the Pd surface structure was evaluated by measuring the kinetic current density and number of electrons transferred for each film. We show through scanning electron microscopy (SEM), x-ray diffraction (XRD), atomic force microscopy (AFM), and voltammetry from rotating disc electrodes (RDEs) that the fastest alkaline ORR kinetics are found on Pd surfaces with high surface roughness, which themselves are composed of fine grains. Such a study is useful for developing membrane electrode assemblies (MEAs) based on directly electrodepositing catalyst onto a conductive diffusion layer.

scholarly journals Photoreversible interconversion of a phytochrome photosensory module in the crystalline state

2019 ◽  
Vol 117 (1) ◽  
pp. 300-307 ◽  
Author(s):  
E. Sethe Burgie ◽  
Jonathan A. Clinger ◽  
Mitchell D. Miller ◽  
Aaron S. Brewster ◽  
Pierre Aller ◽  
...  
Keyword(s):  
Single Crystal ◽  
Blue Light ◽  
Green Light ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Major Barrier ◽  
X Ray ◽  
Spectroscopic Analyses ◽  
Serial Femtosecond Crystallography

A major barrier to defining the structural intermediates that arise during the reversible photointerconversion of phytochromes between their biologically inactive and active states has been the lack of crystals that faithfully undergo this transition within the crystal lattice. Here, we describe a crystalline form of the cyclic GMP phosphodiesterases/adenylyl cyclase/FhlA (GAF) domain from the cyanobacteriochrome PixJ inThermosynechococcus elongatusassembled with phycocyanobilin that permits reversible photoconversion between the blue light-absorbing Pb and green light-absorbing Pg states, as well as thermal reversion of Pg back to Pb. The X-ray crystallographic structure of Pb matches previous models, including autocatalytic conversion of phycocyanobilin to phycoviolobilin upon binding and its tandem thioether linkage to the GAF domain. Cryocrystallography at 150 K, which compared diffraction data from a single crystal as Pb or after irradiation with blue light, detected photoconversion product(s) based on Fobs− Fobsdifference maps that were consistent with rotation of the bonds connecting pyrrole rings C and D. Further spectroscopic analyses showed that phycoviolobilin is susceptible to X-ray radiation damage, especially as Pg, during single-crystal X-ray diffraction analyses, which could complicate fine mapping of the various intermediate states. Fortunately, we found that PixJ crystals are amenable to serial femtosecond crystallography (SFX) analyses using X-ray free-electron lasers (XFELs). As proof of principle, we solved by room temperature SFX the GAF domain structure of Pb to 1.55-Å resolution, which was strongly congruent with synchrotron-based models. Analysis of these crystals by SFX should now enable structural characterization of the early events that drive phytochrome photoconversion.

The Crystal Structure and Magnetic Property of Bi-Substituted Nd2Fe17-x-yTixSiy Intermetallic Compounds

2014 ◽  
Vol 644-650 ◽  
pp. 4950-4955 ◽  
Author(s):  
Li Mei Sun ◽  
Song Bai Han ◽  
Yun Tao Liu ◽  
Dong Feng Chen ◽  
Xiang Feng Liu
Keyword(s):  
Crystal Structure ◽  
Silicon Content ◽  
Unit Cell Volume ◽  
Magnetic Measurements ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Rietveld Refinements ◽  
X Ray ◽  
Si Content ◽  
Ti Content

The synergetic effects of the substitution of Ti and Si for Fe on the crystallographic structure and magnetic properties of Nd2Fe17-x-yTixSiycompounds have been comprehensively investigated by means of x-ray diffraction, neutron diffraction and magnetic measurements. Rietveld refinements of the diffraction data indicate that all the samples crystallize in the rhombohedral Th2Zn17-type structure. For a given Ti content, thea-axis and the unit cell volumeVof Nd2Fe17-x-yTixSiydecrease linearly with increasing silicon content, while thec-axis behaves complicatedly dependent on different Ti content. The site occupancies of Ti and Si in the crystallographic sites significantly change compared to what is observed in the corresponding singly substituted compounds. TheTCof doubly substituted Nd2Fe16.5-yTi0.8Siyand Nd2Fe16.5-yTi0.5Siyis higher than that of singly substituted Nd2Fe16-ySiyfor a lower Si content while the converse behavior is observed for a higher Si content. For a given Ti content, theTCof Nd2Fe17-x-yTixSiycompounds increases with increasing Si content and theMsfirst increases and then decreases. TheMsof Nd2Fe17-x-yTixSiydecreases with the increase of Ti content.

In Situ X-Ray Diffraction and In Situ X-Ray Absorption Spectroscopy for Investigation of Intercalation Batteries: Application to the Alkaline H+/γ-MnO2 system.

1990 ◽  
Vol 210 ◽  
Author(s):  
C. Lévy-Clèment ◽  
C. Mondoloni ◽  
C. Godart ◽  
R. Cortès
Keyword(s):  
Charge Transfer ◽  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Alkaline Batteries ◽  
X Ray ◽  
In Situ Techniques ◽  
X Ray Absorption

AbstractThis paper presents applications of in situ X-ray diffraction and absorption techniques to the study of H+/MnO2 alkaline batteries. The two complementary in situ techniques are described. Investigation of the electrochemical insertion and deinsertion of H+ has been made through its influence on the evolution of the crystallographic structure of γ-MnO2, while investigation of the transfer of e has been undertaken through the variation of the oxidation state of the manganese during the discharging and charging process of a battery. New insights in the understanding of the mechanisms of proton insertion and charge transfer into γ-MnO2 are discussed.

scholarly journals Direct Preparation and Characterization of Copper Pentacyanonitrosylferrate Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
D. R. Do Carmo ◽  
M. M. Souza ◽  
U. O. Bicalho ◽  
V. S. Dos Santos ◽  
J. P. Souza ◽  
...  
Keyword(s):  
Charge Transfer Band ◽  
Cyclic Voltammogram ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Broadening ◽  
Vis Spectroscopy ◽  
Intervalence Charge Transfer ◽  
Direct Preparation ◽  
Graphite Paste Electrode ◽  
Paste Electrode

The present work describes the preparation of nanoparticles of copper pentacyanonitrosyl complexes starting from the compound sodium nitroprusside. Copper pentacyanonitrosylferrate (NCuNP) nanoparticles were successfully synthesized by using deionized water and formamide as solvent. The material was characterized by Fourier-transforming infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and cyclic voltammetry (CV). The results revealed that the electronic spectra of NCuNP exhibited a broad intervalence charge transfer band at 685 nm. An XRD peak broadening pattern of the NCuNP was verified, indicating a particle decrease when formamide is used. The particle size of NCuNP is estimated to be 80 nm. The cyclic voltammogram of the modified graphite paste electrode with NCuNP showed two redox pairs with formal potentialsEθ′=0.36 V andEθ′=0.78 V (ν=20 mV s−1; KCl 1.0 M), attributed to the redox processCuI/CuIIand [FeII(CN)5NO]/[FeIII(CN)5NO], respectively. The graphite paste electrode with NCuNP presents electrocatalytic response for Sulfite determination.

Rietveld Studies on Silicon Substituted Hydroxyapatite

2006 ◽  
Vol 309-311 ◽  
pp. 113-116 ◽  
Author(s):  
Shuo Zou ◽  
Jie Huang ◽  
Serena Best ◽  
William Bonfield
Keyword(s):  
Silicon Content ◽  
Sintering Temperature ◽  
Silicon Concentration ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray ◽  
Similar Dependence ◽  
Initial Silicon ◽  
Distortion Index

Silicon-substituted hydroxyapatite (SiHA) attracts particular interest due its enhanced bioactivity compared with pure hydroxyapatite. In this study we seek to clarify the effects on the lattice parameters of both composition and sintering temperature in experimentally-produced HA and 0.8wt% SiHA, 1.5wt% SiHA and 2.0wt% SiHA sintered at 800oC and 1200oC. X ray diffraction was used to determine the phase purity and crystallographic structure. We found that while the c parameter increased with increasing silicon concentration, the a parameter decreased with initial silicon incorporation then recovered with further increases in silicon incorporation. The calcium (2) channel expanded with silicon incorporation while tetrahedron distortion index (TDI) and the radius of the P channel showed a similar dependence on silicon content as the a parameter.

Study on Novel Structure of Potassium Borate Hydrate: K(H4B5O10)·2(H2O)

2012 ◽  
Vol 531-532 ◽  
pp. 409-412
Author(s):  
Hai Xing Liu ◽  
Fang Fang Jian ◽  
Jing Wang ◽  
Guang Zeng ◽  
Hui Juan Yue ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Packing ◽  
Three Dimensional ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potassium Borate ◽  
Polyhydroxy Compounds ◽  
Novel Structure ◽  
Solution Reaction

Numerous stable complexes of boric acid with polyhydroxy compounds, including tartaric, salicylic, citric, malic, and other acids, are known. The structure of some compounds contains polyanion. In this paper, a novel potassium borate hydrate [K(H4B5O10) •2(H2O)] has been synthesized from a solution reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. Orthorhombic, Aba2. a = 11.0781(14) Å b = 11.1780(15) Å c = 9.0508(11) Å α=β=γ=90°. V= 1120.8(2) Å3. Z=4. Rgt = 0.0244, wRref = 0.0623. T= 298 K. The crystal packing is stabilized by O-H...O hydrogen bonds interaction and three dimensional framwork structure is formed. The work is originality and has a new crystallographic structure shape.

Modification of the Crystallographic Structure of Olanzapine during Solvation by PALS and X-Ray Diffraction Methods

2012 ◽  
Vol 733 ◽  
pp. 92-95
Author(s):  
Maciej Tydda ◽  
Bożena Jasińska ◽  
Anna E. Kozioł ◽  
Irena Wawrzycka-Gorczyca
Keyword(s):  
Crystallographic Structure ◽  
Initial Structure ◽  
X Ray Diffraction ◽  
X Ray

Two selected solvents were incorporated into the olanzapine structure. Molecules located inside the voids in the structure caused the changing of the o-Ps lifetime and intensity. After removing the n-butanol●H2O molecules, the materials returned to its initial structure. Creating the complex with the methanol●H2O leads to the change of the crystallographic structure of the olanzapine.

scholarly journals CRYSTALLOGRAPHIC STRUCTURE AND MAGNETIC PROPERTIES OF PSEUDOBROOKITE Fe2-XNiXTiO5 SYSTEM (x = 0, 0.1, 0.2, 0.3, 0.5 and 1)

2018 ◽  
Vol 19 (2) ◽  
pp. 47
Author(s):  
Yosef Sarwanto ◽  
Wisnu Ari Adi
Keyword(s):  
Magnetic Properties ◽  
Single Phase ◽  
Double Exchange ◽  
Sample Surface ◽  
Crystallographic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Magnetic Spin ◽  
Magnetic Type ◽  
Polygonal Particle

Crystallographic structure and magnetic properties of pseudobrookite Fe2-xNixTiO5 system (x = 0, 0.1, 0.2, 0.3, 0.5 and 1) have been performed through solid state reaction. Pseudobrookite Fe2-xNixTiO5 system was synthesized by mixing of Fe2O3, NiO, and TiO2 with stoichiometry composition using wet mill. The mixture was milled for 5 hours and sintered in the electric chamber furnace at 1000 oC in the air at atmosphere pressure for 5 hours. The refinement against of X-ray diffraction data shows that the sampless with composition of (x = 0) and (x = 0.1) have a single phase with Fe2TiO5 structure. However the samples with composition of (x > 0.1) consist of multiple phases, namely Fe2-xNixTiO5, FeTiO3, Fe2NiO4 and NiO. Particle morphologies of the composition x = 0 and x = 0.1 are homogenous and uniform on the sample surface with a polygonal particle shape and particle size varies. At room temperature, the sample with x=0 is paramagnetic and that with x=0.1 is ferromagnetic. Magnetic phase transformation of this study is the caused by the present of Ni substituted Fe in the system. Thus substitution Ni into Fe on the system pseudobrookite Fe2TiO5 only capable of 0.1 at.% without changing the crystal structure of the material. It means that there is an interaction between the magnetic spin Fe3+ on the 3d5 configurations and Ni2+ on the 3d3 configurations through the mechanism of double exchange. Double exchange mechanism is a magnetic type of exchange that appears between the ions Fe3+ and Ni2+ adjacent in different oxidation states.

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