DEPOLARIZATION BY MERCAPTOACETIC ACID DURING ELECTRODEPOSITION OF COPPER

1956 ◽  
Vol 34 (2) ◽  
pp. 128-132 ◽  
Author(s):  
A. J. Sukava ◽  
C. A. Winkler
Keyword(s):  
Surface Area ◽  
Current Density ◽  
Copper Complex ◽  
Copper Sulphate ◽  
Mercaptoacetic Acid ◽  
Surface Roughening ◽  
Cathode Polarization ◽  
Sulphate Electrolyte ◽  
Consequent Increase

Mercaptoacetic acid (MAA) in acid copper sulphate electrolyte decreased the cathode polarization throughout the course of electrolysis at all concentrations up to 20 mgm./liter. Addition of small amounts of chloride caused further depolarization. When present together with cystine, MAA showed an independence of action. The depolarization caused by MAA was ascribed to a decreased activation overpotential due to substitution of a more readily dischargeable MAA–copper complex for the aquo–copper complex. The additional depolarization due to chloride was ascribed to formation of a still more readily dischargeable chloro–MAA–copper complex. The depolarization in both cases increased with time during prolonged electrolysis, apparently due to surface roughening with, presumably, a consequent increase in surface area and decrease in true current density.

CATHODE SURFACE CHANGES IN THE PRESENCE OF GELATIN DURING ELECTRODEPOSITION OF COPPER

1943 ◽  
Vol 21b (6) ◽  
pp. 125-132 ◽  
Author(s):  
W. Gauvin ◽  
C. A. Winkler
Keyword(s):  
Grain Size ◽  
Current Density ◽  
Copper Sulphate ◽  
Cathode Surface ◽  
Active Area ◽  
Cathode Polarization ◽  
Active Centres ◽  
Main Factor ◽  
Surface Changes

Measurements of the cathode polarization during electrodeposition of copper from acid copper sulphate solutions indicate that introduction of gelatin into the electrolyte decreases the area of the cathode available for deposition, or active area, owing to adsorption of gelatin on the active centres. This decrease in area causes an increase in the true current density, with a resulting increase in cathode polarization, the former being assumed the main factor in causing an increase in the rate of nuclear formation and decrease in grain size.

EFFECT OF GELATIN ON THE CHANGES IN INITIAL CATHODE POLARIZATION DURING ELECTRODEPOSITION OF COPPER

1954 ◽  
Vol 32 (6) ◽  
pp. 581-590 ◽  
Author(s):  
B. I. Parsons ◽  
C. A. Winkler
Keyword(s):  
Steady State ◽  
Current Density ◽  
Copper Sulphate ◽  
Chloride Concentration ◽  
High Current ◽  
Concentration Increase ◽  
Addition Agent ◽  
Cathode Polarization ◽  
Current Densities ◽  
Gelatin Concentration

In the absence of addition agent, the cathode polarization during initial electrolysis of copper from a solution of acid copper sulphate rose almost instantaneously from zero to approximately the steady state polarization. When gelatin was present in the electrolyte, the polarization generally increased to a maximum, Pmax, (in time tmax) then decreased to a minimum, Pmin, (in-time tmin) beyond which it increased to the steady state value, Ps. Generally, Pmax increased to a steady value with an increase in the time, T0, the electrode was in contact with the electrolyte before electrolysis was begun. At low, moderate, and high current densities respectively, tmax increased continuously, passed through a maximum, and decreased continuously with T0.The behavior of tmin approximately paralleled that of tmax. The polarization was linear in the logarithm of the current density; tmax and tmin decreased with increase in current density. The polarization values increased and tmax decreased, with increase in gelatin concentration. Increase of temperature had approximately the same effect as decrease in current density. With both chloride and gelatin present, Pmax was practically independent of T0 and chloride concentration, while Pmin and Ps showed minimum values at about 2 mgm./l. chloride.

CYSTINE AS AN ADDITION AGENT IN THE ELECTRODEPOSITION OF COPPER

1955 ◽  
Vol 33 (5) ◽  
pp. 961-970 ◽  
Author(s):  
A. J. Sukava ◽  
C. A. Winkler
Keyword(s):  
Steady State ◽  
Current Density ◽  
Copper Complex ◽  
Copper Complexes ◽  
Concentration Polarization ◽  
Hydrogen Ion ◽  
Addition Agent ◽  
Agent Behavior ◽  
Low Concentrations ◽  
Sulphate Electrolyte

The steady state polarization of 100 mv. in acid copper sulphate electrolyte, at 2 amp./dm.2, appears to consist of 45 to 50 mv. activation overpotential to deposit aquo–copper complexes, 20 to 25 mv. concentration polarization, and about 30 mv. polarization due to hydrogen ion interference. The presence of cystine in the electrolyte gave rise to polarization–time curves similar to those observed previously with gelatine. The increase of polarization caused by cystine appears to be due to an obstructive effect of adsorbed cystine (or its copper complex), together with an increase of concentration polarization. Cystine alone probably does not affect the activation overpotential. Addition of sufficient chloride virtually eliminated the polarization due to obstruction by cystine, possibly by acting as an electron bridge or by forming more readily dischargeable chloro–cystine–copper complexes. Chloride also eliminated the increment in concentration polarization caused by cystine. Attainment of a minimum total steady state polarization of about 40 mv. in the presence of cystine and chloride appeared to reflect an increase of surface, hence a decrease of true current density with time of deposition. The addition agent behavior of methionine was, in most respects, similar to that of cystine. The behavior of thiourea at low concentrations appeared to be complicated, but the effects of chloride were similar to those observed with gelatine.

Physical Properties Variability of Zinc Powders Obtained by Electrochemical Method

2021 ◽  
Vol 316 ◽  
pp. 689-693
Author(s):  
K.D. Naumov ◽  
V.G. Lobanov
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Bulk Density ◽  
Surface Area ◽  
Specific Surface Area ◽  
Current Density ◽  
Zinc Concentration ◽  
Regulatory Change ◽  
Average Particle ◽  
Zinc Powders

The aim of this paper is to establish a regulatory change of zinc powders key physicochemical properties with varying electroextraction conditions. It was studied influence zinc concentration, alkali concentration and current density. Quantitative dependencies of zinc powders particle size and specific surface area from mentioned electroextraction parameters are shown. At increasing of zinc concentration, decreasing of NaOH concentration and decreasing of current density of powders particle size growth, correspondingly specific surface area is declined. It is indicated, that electrolytic zinc powders bulk density varies from 0.61 g/cm3 to 0.75 g/cm3 with a decrease of average particle size from 121 μm to 68 μm. In comparison, spherical powders bulk density used in various industries is currently 2.45-2.6 g/cm3. In all experiments, metal zinc content varied in the range of 91.1-92.5%, the rest - ZnO. To a greater extent, this indicator depends on powder washing quality from alkali and storage conditions.

scholarly journals Exploring the effect of Ni/Cr contents on the sheet-like NiCr-oxide-decorated CNT composites as highly active and stable catalysts for urea electrooxidation

Clean Energy ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 58-66
Author(s):  
Qiuping Gan ◽  
Benzhi Wang ◽  
Judan Chen ◽  
Jianniao Tian ◽  
Tayirjan Taylor Isimjan ◽  
...  
Keyword(s):  
Surface Area ◽  
Current Density ◽  
High Efficiency ◽  
Catalytic Mechanism ◽  
Low Cost ◽  
Scale Up ◽  
Active Surface ◽  
Environmental Crisis ◽  
Active Surface Area ◽  
Defect Sites

Abstract The developing high-efficiency urea fuel cells have an irreplaceable role in solving the increasingly severe environmental crisis and energy shortages. The sluggish six-electron dynamic anodic oxidation reaction is the bottleneck of the rapid progress of urea fuel-cell technology. To tackle this challenge, we select the NiCr bimetallic system due to the unique synergic effect between the Ni and the Cr. Moreover, better conductivity is assured using carbon nanotubes (CNTs) as the support. Most importantly, we use a simple hydrothermal method in catalyst preparation for easy scale-up at a low cost. The results show that the hybrid catalysts of NiCrx-oxide-CNTs with different Ni/Cr ratios show much better catalytic performance in terms of active surface area and current density as compared to that of Ni-hydro-CNTs. The optimized NiCr2-oxide-CNTs catalyst exhibits not only the largest electrochemically active surface area (ESA, 50.7 m2 g−1) and the highest urea electrocatalytic current density (115.6 mA cm−2), but also outstanding long-term stability. The prominent performance of the NiCr2-oxide-CNTs catalyst is due to the combined effect of the improved charge transfer between Ni and Cr species, the large ESA, along with an elegant balance between the oxygen-defect sites and hydrophilicity. Moreover, we have proposed a synergistically enhanced urea catalytic mechanism.

Increasing Current Density of Li-Mediated Ammonia Synthesis with High Surface Area Copper Electrodes

2021 ◽  
pp. 36-41
Author(s):  
Katja Li ◽  
Sarah G. Shapel ◽  
Degenhart Hochfilzer ◽  
Jakob B. Pedersen ◽  
Kevin Krempl ◽  
...  
Keyword(s):  
Surface Area ◽  
Current Density ◽  
Ammonia Synthesis ◽  
High Surface ◽  
High Surface Area ◽  
Copper Electrodes

Hydrothermally reduced Graphene Oxide coated Carbon Cloth for Flexible Supercapacitors

2021 ◽  
pp. 1-24
Author(s):  
Subhakaran Singh Rajaputra ◽  
Nagalakshmi P ◽  
Anjaneyulu Yerramilli ◽  
Naga Mahesh K
Keyword(s):  
Surface Area ◽  
Hydrothermal Treatment ◽  
Current Density ◽  
Evaluation Studies ◽  
Superior Performance ◽  
Bet Surface Area ◽  
Carbon Cloth ◽  
Angle Measurements ◽  
Physico Chemical ◽  
Treated Carbon

Abstract Hydrothermally synthesized Graphene (HRG) was tested for its supercapacitive behavior using nickel (Ni) and hydrothermally treated carbon cloth as current collectors, respectively. Performance evaluation studies were carried out in an in-house fabricated SS cell. Commercially obtained untreated carbon cloth (CCUn) was exfoliated via oxidation (CCOx) followed by hydrothermal treatment to obtain a reduced carbon cloth (CCHy). The Physico-chemical and electrochemical properties of carbon cloth by oxidative exfoliation and hydrothermal treatment have been studied using SEM, XRD, FTIR, BET surface area, Contact angle measurements, cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and EIS. HRG coated on the CCHy (HRG-CCHy) had shown superior performance and endurance compared to HRG coated on Ni strip (HRG-Ni), with distinguishable specific capacitances (Cs) of 170 and 134 F g-1 at 0.5 A g-1 current density, respectively. At a higher 10 A g-1 current density, HRG-CCHy, and HRG-Ni have displayed distinctive specific capacitances of 120 and 80 F g-1, respectively, indicating a comparative decline in the performance of HRG-Ni with respect to HRG-CCHy. Endurance study performed for 5000 cycles at 2 A g-1, resulted in HRG-CCHy and HRG-Ni, retaining 88% and 81% of their initial specific capacitances. At 1 kW kg-1 of power density, HRG-CCHy displayed a 5.5 Wh kg-1 of energy density. The electrochemical performance of HRG-CCHy may be attributed to exceptional properties like high wettability, low impedance, high pore volume, and specific surface area.

scholarly journals High Surface Area Nanoporous Graphitic Carbon Materials Derived from Lapsi Seed with Enhanced Supercapacitance

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 728 ◽  
Author(s):  
Lok Kumar Shrestha ◽  
Rekha Goswami Shrestha ◽  
Subrata Maji ◽  
Bhadra P. Pokharel ◽  
Rinita Rajbhandari ◽  
...  
Keyword(s):  
Surface Area ◽  
Current Density ◽  
Electrode Materials ◽  
Carbon Materials ◽  
High Surface ◽  
High Surface Area ◽  
Graphitic Carbon ◽  
High Rate ◽  
Surface Areas ◽  
Nanoporous Carbon Materials

Nanoporous activated carbon materials derived from agro-wastes could be suitable low-cost electrode materials for high-rate performance electrochemical supercapacitors. Here we report high surface area nanoporous carbon materials derived from Lapsi seed agro-waste prepared by zinc chloride (ZnCl2) activation at 700 °C. Powder X-ray diffraction (pXRD) and Raman scattering confirmed the amorphous structure of the resulting carboniferous materials, which also incorporate oxygen-containing functional groups as confirmed by Fourier transform infrared (FTIR) spectroscopy. Scanning and transmission electron microscopy (SEM and TEM) analyses revealed the granular, nanoporous structures of the materials. High-resolution TEM (HR-TEM) confirmed a graphitic carbon structure containing interconnected mesopores. Surface areas and pore volumes of the materials were found, respectively, in the ranges from 931 to 2272 m2 g−1 and 0.998 to 2.845 cm3 g−1, and are thus superior to commercially available activated carbons. High surface areas, large pore volumes and interconnected mesopore structures of these Lapsi seed-derived nanoporous carbon materials lead to their excellent electrochemical supercapacitance performance in aqueous electrolyte (1 M H2SO4) with a maximum specific capacitance of 284 F g−1 at a current density of 1 A g−1. Furthermore, the electrodes showed high-rate capability sustaining 67.7% capacity retention even at high current density of 20 A g−1 with excellent cycle stability achieving 99% capacitance retention even after 10,000 charge–discharge cycles demonstrating the potential of Lapsi seed derived nanoporous carbons as suitable electrode materials in high-performance supercapacitor devices.

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