Influence of Water and Other Contaminants in Electrolyte Solutions on Lithium Electrodeposition

1997 ◽  
Vol 496 ◽  
Author(s):  
T. Fujieda ◽  
S. Koike ◽  
S. Higuchi
Keyword(s):  
Cyclic Voltammetry ◽  
Reaction Mechanism ◽  
Electrode Surface ◽  
Redox Reaction ◽  
Electrolyte Solutions ◽  
Potential Range ◽  
Nickel Electrode ◽  
Influence Of Water ◽  
The One ◽  
Wide Potential

ABSTRACTElectrochemistry of a nickel electrode in propylene carbonate [PC] containing LiClO4, LiCF3SO3, LiPF6 was studied through a micro electrode (φ =25 μ m) techniques in the wide potential range between +4.5 and -0.2 V vs. Li/Li+. Common pronounced peaks were observed in the potential range positive to lithium electrodeposition on nickel in all electrolyte solutions examined. Thus, these peaks can be attributed to reactions related to Li+ or commonly contained contaminants such as water and acids. In particular, the peak which appeared at the most negative potential seemed to be underpotential deposition (UPD) of lithium.To prove this hypothesis a nickel electrode in highly dried PC (water content : 3 – 8 ppm) intentionally contaminated with a small amount of water and CF3COOH was examined via cyclic voltammetry. Changing the content of water and acid (and its ratio) in PC resulted in a variety of voltammograms and one of them was identical to the one observed in PC containing lithium electrolytes. These facts preclude the existence of UPD of lithium on nickel in the electrolyte solutions. Instead, the existence of NiOH on nickel and its redox reaction mechanism have been postulated. The mechanism is consistent with the experimental facts : a nickel electrode passivates in PC with a small amount of water, and a small amount of acid, CF3COOH, can prevent passivation. The vicinity of the electrode surface may be exposed to an alkaline atmosphere owing to the reduction product of water. This seems to be the cause of troubles we run into with the electrodes at cathodic potentials

Laser Photocatalysis of the Chlorophyll Dye Using the Cyclic Voltammetry Method

2021 ◽  
Vol 882 ◽  
pp. 143-154
Author(s):  
Huda S. Alhasan
Keyword(s):  
Cyclic Voltammetry ◽  
Laser Light ◽  
Potential Range ◽  
Carbon Electrode ◽  
Total Chlorophyll ◽  
Tetrabutylammonium Perchlorate ◽  
Oxidation Peak ◽  
Solution Ph ◽  
Cyclic Voltammetry Method ◽  
Wide Potential

Cyclic voltammetry is a widely used technique in electrochemistry due to its simplicity and large amount of data and information that can be obtained. This study utilises this technique to study chlorophyll a and total chlorophyll (Tchl) alongside a laser light to induce photosynthesis. No oxidative peak was observed, regardless of the solution pH in either a dark or light environment when using a solution with an electrolyte of tetrabutylammonium perchlorate (TBAP) in both dichloromethane (DCM) and acetonitrile (MeCN), whereas in a solution of aqueous HCl a small anodic peak was observed. The concentration of the droplet of Tchl pigment on the surface of macro glassy carbon electrode (GCE) was increased, which resulted in a similar trend and the oxidation peak was observed to be slightly larger when in the presence of light. It was observed that the filtered solution of Tchl pigment produced a weaker signal than the unfiltered solution and there were slightly reduced oxidative peak currents when the concentration of VK1 was increased. were no observed changes in the peak charges or currents over a wide potential range (0.0, 0.2, 0.4, 0.6 and 0.8 V) in the presence or absence of light by using coulometry and amperometry methods, therefore, more information on the 3-D formation is required for the photoreduction processes.

PATTERN FORMATION IN ELECTROLESS DEPOSITION

Fractals ◽  
1995 ◽  
Vol 03 (02) ◽  
pp. 371-375 ◽  
Author(s):  
IWAO MOGI ◽  
SUSUMU OKUBO
Keyword(s):  
Cyclic Voltammetry ◽  
Reaction Mechanism ◽  
Pattern Formation ◽  
Thin Layer ◽  
Redox Reaction ◽  
Electroless Deposition ◽  
Diffusion Limited Aggregation ◽  
Diffusion Limited ◽  
Silver Metal ◽  
Gold Metal

Metal-forest patterns of electroless deposits of silver and gold in thin-layer aqueous solutions were studied in connection with their chemical reactions. While the silver metal-forest with a simple redox reaction of Cu and Ag+ showed a DLA (diffusion limited aggregation)-like pattern, the gold metal-forest with a redox reaction of Pb and [Formula: see text] showed a DBM (dense branching morphology). The reaction mechanism of the latter was investigated by means of cyclic voltammetry, and the growth condition of the DBM is discussed.

Interfacial interactions and the heterogeneous one-electron reduction of methyl viologen

1987 ◽  
Vol 52 (5) ◽  
pp. 1097-1114 ◽  
Author(s):  
Michael Heyrovský ◽  
Ladislav Novotný
Keyword(s):  
Electron Transfer ◽  
Radical Cation ◽  
Electrode Surface ◽  
Methyl Viologen ◽  
Potential Range ◽  
Standard Redox Potential ◽  
Mercury Electrodes ◽  
Electron Reduction ◽  
The One ◽  
Surface Redox

The one-electron reversible electroreduction of methyl viologen to its radical cation in aqueous solutions on mercury electrodes proceeds, according to potential, concentration and time of electrolysis, in various ways. Methyl viologen is adsorbed in flat orientation at the electrode surface; it undergoes a surface redox process in π-interaction with the metal in a potential range positive by about 0.2 V of the beginning of the electroreduction. The actual reduction starts by electron transfer followed by adsorption of the radical cation and, at higher concentrations and in a narrow potential range, by crystallization at the electrode surface of a salt of the radical cation. In solution near the electrode the radical cation dimerizes and the dimer also adsorbs at the electrode. In the region of the standard redox potential and more negative the reduction proceeds by electron transfer from the electrode covered by a layer of the radical cation or of its dimer.

Understanding the redox reaction mechanism of vanadium electrolytes in all-vanadium redox flow batteries

2019 ◽  
Vol 21 ◽  
pp. 321-327 ◽  
Author(s):  
Chanyong Choi ◽  
Hyungjun Noh ◽  
Soohyun Kim ◽  
Riyul Kim ◽  
Juhyuk Lee ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Redox Reaction ◽  
Redox Flow Batteries ◽  
Flow Batteries ◽  
Vanadium Redox

Glucose Molecularly Imprinted Electrochemical Sensor Based on Chitosan and Nickel Oxide Electrode

2014 ◽  
Vol 1052 ◽  
pp. 215-219 ◽  
Author(s):  
Huai Xiang Li ◽  
Wei Yao ◽  
Qiong Wu ◽  
Wen Sha Xia
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Sensor ◽  
Molecularly Imprinted Polymers ◽  
Glucose Measurement ◽  
Nickel Electrode ◽  
Oxide Electrode ◽  
Molecularly Imprinted ◽  
Imprinted Polymers ◽  
Nickel Oxide Electrode ◽  
Scanning Electron

In this work, A molecularly imprinted polymers (MIPs) electrochemical sensor based on chitosan (CS) and nickel electrode was constructed, finally used in glucose measurement. The MIPs sensor was prepared through electrodepositing glucose–CS composited film on the electrochemical treated nickel then removing glucose from the film via water elution. The morphology and electrochemical properties of the sensor were characterized via scanning electron microscope (SEM) , cyclic voltammetry (CV), respectively. Amperometric responses of the CS (MIP)-NiO electrode toward glucose was well-proportional to the concentration of the range from 10 μM to 200 μM. The developed sensor obtained the specific recognition to glucose against coexisting interferences such as oxalic acid, uric acid and ascorbic acid.

scholarly journals Colloidal ReO3 Nanocrystals: Extra Re d-Electron Instigating a Plasmonic Response

2019 ◽  
Author(s):  
Sandeep Ghosh ◽  
Hsin-Che Lu ◽  
Shin Hum Cho ◽  
Thejaswi Maruvada ◽  
Murphie C. Price ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
Bulk Material ◽  
Optical Modulation ◽  
Colloidal Synthesis ◽  
Localized Surface Plasmon ◽  
Potential Range ◽  
Absorption Bands ◽  
Polar Solvents ◽  
Free Electron Density ◽  
Wide Potential

<div><div><div><p>Rhenium (+6) oxide (ReO3) is metallic in nature, which means it can sustain localized surface plasmon resonance (LSPR) in its nanocrytalline form. Herein, we describe the colloidal synthesis of nanocrystals (NCs) of this compound, through a hot-injection route entail- ing the reduction of rhenium (+7) oxide with a long chain ether. This synthetic protocol is fundamentally different from the more widely em- ployed nucleophilic lysing of metal alkylcarboxylates for other metal oxide NCs. Owing to this difference, the NC surfaces are populated by ether molecules through an L-type coordination along with covalently bound (X-type) hydroxyl moieties, which enables easy switching from nonpolar to polar solvents without resorting to cumbersome ligand exchange procedures. These as-synthesized NCs exhibit absorption bands at around 590 nm (≈2.1 eV) and 410 nm (≈3 eV), which were respectively ascribed to their LSPR and interband absorptions by Mie theory simulations and Drude modeling. The LSPR response arises from the oscillation of free electron density created by the extra Re d-electron per ReO3 unit in the NC lattice, which resides in the conduction band. Further, the LSPR contribution facilitates the observation of dynamic optical modulation of the NC films as they undergo progressive electrochemical charging via ion (de)insertion. Ion (de)insertion leads to distinct dynamic optical signatures, and these changes are reversible in a wide potential range depending on the choice of the ion (lithium or tetrabu- tylammonium). Nanostructuring in ReO3 and the description of the associated plasmonic properties of these NCs made this optical modulation feasible, which were hitherto not reported for the bulk material. We envisage that the synthetic protocol described here will facilitate further exploration of such applications and fundamental studies of these plasmonic NCs</p></div></div></div>

scholarly journals Electrochemical synthesis of poly(2-methyl aniline): electrochemical and spectroscopic characterization

2001 ◽  
Vol 66 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Aleksandra Buzarovska ◽  
Irena Arsova ◽  
Ljubomir Arsov
Keyword(s):  
Raman Spectroscopy ◽  
Cyclic Voltammetry ◽  
Redox Reactions ◽  
Electrochemical Polymerization ◽  
Spectroscopic Characterization ◽  
Potential Range ◽  
Cyclic Voltammograms ◽  
Impedance Measurements ◽  
Order Of Magnitude ◽  
Poly Aniline

Poly(2-methyl aniline) or poly(ortho-toluidine), as ring substituted derivative of aniline, has been synthesized electrochemically in various concentrations of H2SO4 and HCl, and then characterized by cyclic voltammetry, as well as by impedance and Raman spectroscopy. The cyclic voltammograms of poly(o-toluidine) and poly(aniline) show that the electrochemical polymerization of these two polymers proceeds by almost identical mechanisms. The Raman spectroscopical measurements suggest that the redox reactions of poly(aniline) and poly(o-toluidine) are similar in the potential range between -0.2 and 0.7V vs. SCE. The impedance measurements showed that the conductivity of poly(o-toluidine) is an order of magnitude lower than that of the corresponding poly(aniline) form.

scholarly journals Understanding the reaction mechanism of Kolbe electrolysis on Pt anodes

2021 ◽  
Author(s):  
Sihang Liu ◽  
Nitish Govindarajan ◽  
Hector Prats ◽  
Karen Chan
Keyword(s):  
Reaction Mechanism ◽  
Potential Range ◽  
Microkinetic Model ◽  
Rate Determining Step ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Tafel Slopes ◽  
Kolbe Electrolysis ◽  
Kolbe Reaction ◽  
Rate Limiting

Kolbe electrolysis has been proposed an efficient electrooxidation process to synthesize (un)symmetrical dimers from biomass-based carboxylic acids. However, the reaction mechanism of Kolbe electrolysis remains controversial. In this work, we develop a DFT- based microkinetic model to study the reaction mechanism of Kolbe electrolysis of acetic acid (CH3COOH) on both pristine and partially oxidized Pt anodes. We show that the shift in the rate-determining step of oxygen evolution reaction (OER) on Pt(111)@α-PtO2 surface from OH* formation to H2O adsorption gives rise to the large Tafel slopes, i.e., the inflection zones, observed at high anodic potentials in experiments on Pt anodes. The activity passivation as a result of the inflection zone is further exacerbated in the presence of Kolbe species (i.e., CH3COO* and CH3*). Our simulations find the CH3COO* decarboxylation and CH3* dimerization steps determine the activity of Kolbe reaction during inflection zone. In contrast to the Pt(111)@α-PtO2 surface, Pt(111) shows no activity towards Kolbe products as the CH3COO* decarboxylation step is limiting throughout the considered potential range. This work resolves major controversies in the mechanistic analyses of Kolbe electrolysis on Pt anodes: the origin of the inflection zone, and the identity of the rate limiting step.

Analysis of a Tunable CMOS-compatible Multilayer Waveguide Structure for Dual Polarizer-modulator Operation

2021 ◽  
Author(s):  
Renan Silva Santos ◽  
Maria A. G. Martinez
Keyword(s):  
Chemical Potential ◽  
Extinction Ratio ◽  
Silicon Layer ◽  
Individual Case ◽  
Waveguide Structure ◽  
Potential Range ◽  
Figures Of Merit ◽  
Silicon Waveguide ◽  
The One ◽  
Better Than

Abstract A multilayer structure using graphene on a silicon waveguide is introduced and optimized to operate as a tunable TE-pass polarizer at 1310 nm or 1550 nm, a tunable TE/TM modulator at 1310 nm or 1550 nm, and a dual operation as a modulator at 1310 nm and a polarizer at 1550 nm. The analysis is based on the waveguide structure modal loss, the 2D graphene layer optical properties and its dependency on the applied chemical potential. The optimization is done by varying waveguide height and choosing the one with best figures of merit for each individual case and for the dual operation, the value that causes the least impairment overall is chosen. The polarizer tunability at 1310 nm or 1550 nm is attainable setting the applied chemical potential range from 0.55–0.65 eV or 0.45–0.55 eV, respectively. For the modulator tunability at 1310 nm or 1550 nm, the applied chemical potential range from 0.45–0.55 eV or 0.35–0.45 eV, respectively. The optimized waveguide silicon layer around 210 nm guarantees an extinction ratio better than 0.056 dB/µm for the polarizer and better than 0.045/0.133 dB/µm for the TE/TM modulator at 1310 nm, and better than 0.034 dB/µm for polarizer and better than 0.053/0.137 dB/µm for TE/TM modulator at 1550 nm. Further, the setting the chemical potential range at 0.45–0.55 eV, allows dual polarizer-modulator operation, with the modulator operating at 1310 nm and the polarizer operating at 1550 nm, presenting an extinction ratio better than 0.045 dB/µm and 0.034 dB/µm respectively. In all situations analyzed, insertion loss is lower than 0.007 dB/µm. The advantage of the structure in comparison with other similar devices relies in its versatility to operate as both modulator and polarizer, in different wavelengths, via a proper choosing of the applied chemical potential.

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