Abstract:-Zinc electrowinning is performed with the application of a current through insoluble electrodes (Pb-Ag), causing the electrolysis of zinc sulfate, with or without impurities, and zinc deposition on the cathode of aluminum. The impurities can reduce the current efficiency and increase the energy consumption in zinc electrolysis. In this work, the effect of nickel and magnesium on zinc electrodeposition was studied using the electrochemical techniques of galvanostatic deposition and cyclic voltammetry. Addition… Show more
“…In contrast to the onset potential of silver electrodeposition at the 1st scan cycle, the reduction of silver ions starts at a more positive potential from the 2nd scan cycle onwards, which is at ∼−280 mV. As platinum working electrode (which is different from the deposited metal) is employed, the initiation of nucleation normally consumes more energy to produce the first nucleus [20]. Besides that, the presence of nondissolved silver film on the electrode may also facilitate the nucleation and growth processes during the 2nd scan cycle.…”
Section: Cyclic Voltammetry Of Ag/ag + At Rotating Disk Platinummentioning
The electrochemical processes in solutions with a much lower amount of free cyanide (<10 g/L KCN) than the conventional alkaline silver electrolytes were first explored by using cyclic voltammetry. The electrochemical behavior and the effect of KAg(CN)2, KCN, and KNO3electrolytes and solution pH on the electrodeposition and dissolution processes were investigated. Moreover, suitable working conditions for high speed, low cyanide silver electrodeposition were also proposed. Both silver and cyanide ions concentration had significant effects on the electrode polarization and deposition rate. The onset potential of silver electrodeposition could be shifted to more positive values by using solutions containing higher silver and lower KCN concentration. Higher silver concentration also led to higher deposition rate. Besides maintaining high conductivity of the solution, KNO3might help reduce the operating current density required for silver electrodeposition at high silver concentration albeit at the expense of slowing down the electrodeposition rate. The silver dissolution consists of a limiting step and the reaction rate depends on the amount of free cyanide ions. The surface and material characteristics of Ag films deposited by low cyanide solution are also compared with those deposited by conventional high cyanide solution.
“…In contrast to the onset potential of silver electrodeposition at the 1st scan cycle, the reduction of silver ions starts at a more positive potential from the 2nd scan cycle onwards, which is at ∼−280 mV. As platinum working electrode (which is different from the deposited metal) is employed, the initiation of nucleation normally consumes more energy to produce the first nucleus [20]. Besides that, the presence of nondissolved silver film on the electrode may also facilitate the nucleation and growth processes during the 2nd scan cycle.…”
Section: Cyclic Voltammetry Of Ag/ag + At Rotating Disk Platinummentioning
The electrochemical processes in solutions with a much lower amount of free cyanide (<10 g/L KCN) than the conventional alkaline silver electrolytes were first explored by using cyclic voltammetry. The electrochemical behavior and the effect of KAg(CN)2, KCN, and KNO3electrolytes and solution pH on the electrodeposition and dissolution processes were investigated. Moreover, suitable working conditions for high speed, low cyanide silver electrodeposition were also proposed. Both silver and cyanide ions concentration had significant effects on the electrode polarization and deposition rate. The onset potential of silver electrodeposition could be shifted to more positive values by using solutions containing higher silver and lower KCN concentration. Higher silver concentration also led to higher deposition rate. Besides maintaining high conductivity of the solution, KNO3might help reduce the operating current density required for silver electrodeposition at high silver concentration albeit at the expense of slowing down the electrodeposition rate. The silver dissolution consists of a limiting step and the reaction rate depends on the amount of free cyanide ions. The surface and material characteristics of Ag films deposited by low cyanide solution are also compared with those deposited by conventional high cyanide solution.
“…High purity (99.999%) silver single crystals with specific orientations of the (100), (110) and (111) were purchased from Goodfellow Cambridge Ltd, UK. These one-sided polished single crystals have diameter of 10 mm and thicknesses of 2 mm for the (100) and (111) samples and 1 mm for the (110) sample. The orientation tolerance of these single crystals was ± 3º.…”
Section: Methodsmentioning
confidence: 99%
“…2D (Ra) and 3D (Sdr) roughness parameters were used to characterize the surface texture of single crystal silver. It is found that surface roughness plays a more critical role in determining the reflectance while the crystal (100), (110) and (111) orientations have negligible effect on the silver reflectance. Moreover, correlations in predicting the silver reflectance by employing either 2D or 3D roughness parameters as the input variables have also been proposed.…”
Section: /7/2017mentioning
confidence: 99%
“…Table Captions xii electrons and x-ray (redrawn from [80]). 100, Ag (110) and Ag (111) with different specular reflectance (a) -(c) R450nm…”
Section: Table Of Contentsmentioning
confidence: 99%
“…is employed, the initiation of nucleation normally consumes more energy to produce the first nucleus [111]. Besides that, the presence of non-dissolved silver film on the electrode may also facilitate the nucleation and growth processes during the 2 nd scan cycle.…”
Section: Cyclic Voltammetry Of Ag/ag + At Rotating Disk Platinum Elecmentioning
Improving light extraction efficiency is vital for ensuring the performance of high brightness light emitting diodes (LEDs). One of the improvement methods is to electrodeposit highly reflective silver thin films on the leadframe surfaces. Due to stricter rules and regulations, less toxic electrolytes have become more favorable in the plating industries. To date, comprehensive study on the key factors for developing highly reflective Ag films has not been widely explored. This thesis aims not only to develop low cyanide WOLED White Organic LED XPS X-ray Photoelectron Spectroscopy Abbreviations xxii XRD X-Ray Diffraction XRF X-Ray Fluorescence 2. To understand the effect of surface morphology, crystal structure, film texture and chemical composition on the optical properties of the plated films. 3. To build up a statistical model to simulate the above correlations for demonstrating the influences of material design, process selection, and surface characteristics on optical properties.
In the case of a conventional zinc bromide electrolyte solution using zinc chloride as additive, an undesirable reaction occurs. In this reaction, complex anions form between zinc and the chloride ions during charging and discharging. To overcome this problem, this paper describes an excellent electrolyte solution using zinc perchlorate as the additive, resulting in a highly stable and reversible reaction in zinc-bromine flow cells. To show the effectiveness of the proposed solution, electrochemical analyses are carried out using cyclic voltammetry, a miniature zinc-bromine flow cell, and scanning electron microscopy. The solution is then compared with the conventional electrolyte solution using zinc chloride as the supporting material. Experimental results show that use of the zinc perchlorate additive increases the rate of zinc dissolution by improving the reaction rate of bromine in the catholyte half-cell. Consequently, this arrangement allows a highly stable operation for improving the current efficiency of zinc-bromine flow batteries.
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