Iron phosphide nanoparticles as an efficient electrocatalyst for the OER in alkaline solution

2016 ◽  
Vol 4 (25) ◽  
pp. 9750-9754 ◽  
Author(s):  
J. Masud ◽  
S. Umapathi ◽  
N. Ashokaan ◽  
M. Nath
Keyword(s):  
Oxygen Evolution ◽  
Alkaline Medium ◽  
Alkaline Solution ◽  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Iron Phosphide ◽  
Onset Potential ◽  
Low Overpotential

Ultrasmall FeP nanoparticles have been reported as an efficient oxygen evolution electrocatalyst in alkaline medium with low onset potential for oxygen evolution and require low overpotential to reach 10 mA cm−2 exchange current density.

Effect of Current Densities on the Microstructure and Electrochemical Behavior of the Porous β-PbO2 Electrode

2019 ◽  
Vol 956 ◽  
pp. 21-34
Author(s):  
Shi Chuan Wang ◽  
Sheng Chen ◽  
Bu Ming Chen ◽  
Tai Xiang Huang ◽  
Hui Huang ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Surface Morphology ◽  
Oxygen Evolution ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Active Surface Area ◽  
Galvanostatic Polarization

In order to obtain a titanium-based PbO2 electrode with high electrocatalytic activity and good stability, A porous β-PbO2 electrode is prepared by electrodepositing on titanium substrate Sn-Sb-RuOx coating. The surface morphology and phase analysis of the porous β-PbO2 electrode prepared at different current density were investigated by SEM and XRD. Results showed that the current density changes the surface morphology and active surface area of the porous β-PbO2 electrode. When the current density is 2 A/dm2, the surface of the porous β-PbO2 prepared by electrodeposition has a uniform porous morphology with a pore diameter of 50-200 µm with main crystal phase of β-PbO2. Influence of current density on the electrochemical activity of the electrode was analyzed using anodic polarization curve, electrochemical impedance spectroscopy and galvanostatic polarization. Results revealed that with the increase of current density, the oxygen evolution potential of the porous β-PbO2 electrode decreases first and then increases while the exchange current density first increases and then decreases. When the current density is 2 A/dm2, the oxygen evolution potential is 2.0075 V(at 0.05 A/cm2) and the maximum exchange current density is 1.77×10-4 A/cm2. According to the electrochemical impedance spectroscopy, when the current density is 2 A/dm2, Qf and Qdl are the largest, Rf and Rct are the smallest, and the RF first increases and then decreases with the current density increases. When the current density is 2 A/dm2, the maximum RF value is 655.7. The results with galvanostatic polarization at current density of 0.05 A/cm2 showed that the electrode has a minimum electrode voltage of 2.05 V at a current density of 2 A/dm2. Accelerated life experiments were carried out in 2 g/L Cl- and 150 g/L H2SO4 bath at 25 °C, and the porous β-PbO2 electrode obtained under the current density of 2 A/dm2 has the longest life, and the electrode life is 68 h, which is 2.5 times of the PbO2 electrode obtained under the current density of 4 A/dm2.

scholarly journals Estimation of the exchange current density and comparative analysis of morphology of electrochemically produced lead and zinc deposits

2017 ◽  
Vol 82 (5) ◽  
pp. 539-550
Author(s):  
Nebojsa Nikolic ◽  
Predrag Zivkovic ◽  
Goran Brankovic ◽  
Miomir Pavlovic
Keyword(s):  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Diffusion Current ◽  
Electron Microscopic ◽  
Zinc Electrodeposition ◽  
Lead And Zinc ◽  
Current Densities ◽  
Limiting Diffusion Current ◽  
Zinc Deposits

The processes of lead and zinc electrodeposition from the very dilute electrolytes were compared by the analysis of polarization characteristics and by the scanning electron microscopic (SEM) analysis of the morphology of the deposits obtained in the galvanostatic regime of electrolysis. The exchange current densities for lead and zinc were estimated by comparison of experimentally obtained polarization curves with the simulated ones obtained for the different the exchange current density to the limiting diffusion current density ratios. Using this way for the estimation of the exchange current density, it is shown that the exchange current density for Pb was more than 1300 times higher than the one for Zn. In this way, it is confirmed that the Pb electrodeposition processes are considerably faster than the Zn electrodeposition processes. The difference in the rate of electrochemical processes was confirmed by a comparison of morphologies of lead and zinc deposits obtained at current densities which corresponded to 0.25 and 0.50 values of the limiting diffusion current densities.

Correlation of Exchange Current Density j₀ and the Standard Potential of the Metal Electrodes EM⁰ for the Hydrogen Evolution Reaction (HER)

2020 ◽  
Vol MA2020-01 (46) ◽  
pp. 2604-2604
Author(s):  
Daniel Lee Parr ◽  
Kasun Dadallagei ◽  
Sidney J. DeBie ◽  
Joshua R Coduto ◽  
Christian D Haas ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Standard Potential ◽  
Metal Electrodes
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