scholarly journals Estimation of Exchange Current Density for the Hydrogen Evolution Reaction of Titanium in Sulfuric Acid Solution

2018 ◽  
Vol 82 (11) ◽  
pp. 431-436
Author(s):  
Osami Seri
2020 ◽  
Vol MA2020-01 (46) ◽  
pp. 2604-2604
Author(s):  
Daniel Lee Parr ◽  
Kasun Dadallagei ◽  
Sidney J. DeBie ◽  
Joshua R Coduto ◽  
Christian D Haas ◽  
...  

2005 ◽  
Vol 144 (2) ◽  
pp. 338-345 ◽  
Author(s):  
Y.M. Wu ◽  
W.S. Li ◽  
X.M. Long ◽  
F.H. Wu ◽  
H.Y Chen ◽  
...  

Author(s):  
Maria М. Kuzminykh ◽  
Viktoria V. Panteleeva ◽  
Anatoliy B. Shein

The kinetics of hydrogen evolution reaction on FeSi2-electrode in 0.5 M H2SO4 solution has been studied using methods of polarization and impedance measurements. With the help of diagnostic criteria for the hydrogen evolution reaction mechanisms based on the analysis of the dependence of the parameters of the equivalent electric circuit on overvoltage, it was established that the reaction of hydrogen evolution on iron disilicide in the sulfuric acid solution proceeds along the discharge - electrochemical desorption route, where desorption is the rate-determining stage. Both stages are irreversible, the transfer coefficients α of the stages are equal, simultaneously the hydrogen absorption reaction by the electrode material proceeds in the kinetic mode (in the whole investigated range of potentials). It was found that the adsorption of atomic hydrogen is described by the equation of the Langmuir isotherm. The influence of thin oxide film on the hydrogen evolution kinetics is noted. The influence of various methods of modifying of the surface of FeSi2-electrode on the kinetics and mechanism of the cathodic process has been studied. It was found that the modification of the disilicide surface by hydrogenation at a current density of i = 30 mA/cm2, an anodic etching in 0.5 M H2SO4 at the potential E = 0.4 V relative to the standard hydrogen electrode, an anodic etching in 1.0 M NaOH at the potential E = 0.1 V, chemical etching in 5.0 M NaOH at 70 °C reduce the overvoltage of hydrogen evolution, but the mechanism of the cathodic process does not change as a result of the electrode modification. Reduction of the overvoltage of hydrogen evolution on iron disilicide is due to the action of two factors: the development of the surface and the change in the composition of the surface layer of the electrode. It has been concluded that FeSi2 in the sulfuric acid solution is a promising electrode material that exhibits activity in the electrolytic hydrogen evolution reaction.


2021 ◽  
Vol MA2021-01 (46) ◽  
pp. 1864-1864
Author(s):  
Daniel Parr ◽  
Kasun Saweendra Rathnatunga Dadallagei ◽  
Sidney Debie ◽  
Joshua Richard Coduto ◽  
Christian D Haas ◽  
...  

2020 ◽  
Vol 85 (3) ◽  
pp. 347-352
Author(s):  
Nebojsa Nikolic

The short survey of the dependence of the shape of electrolytically produced powder particles on the exchange current density for metal deposition and overpotential for hydrogen evolution reaction is presented. The decrease of the exchange current density leads to a branching of dendrites and their transformation from needle-like and the two-dimensional (2D) fern-like to the three-dimensional (3D) pine-like shapes. Vigorous hydrogen evolution inhibits the dendritic growth leading to a formation of cauliflower-like and the spongy-like particles. The very thin needles were obtained by molten salt electrolysis. Mechanisms responsible for the formation of both the dendritic (the general theory of disperse deposits formation) and the cauliflower-like and the spongy-like particles (the concept of ?effective overpotential?) were also mentioned.


2020 ◽  
Vol 10 (2) ◽  
pp. 111-126
Author(s):  
Nebojša D. Nikolić

In this study, comprehensive survey of formation of disperse forms by the electrolysis from aqueous electrolytes and molten salt electrolysis has been presented. The shape of electrolitically formed disperse forms primarily depends on the nature of metals, determined by the exchange current density (j0) and overpotential for hydrogen evolution reaction as a parallel reaction to metal electrolysis. The decrease of the j0 value leads to a change of shape of dendrites from the needle-like and the 2D fern-like dendrites (metals characterized by high j0 values) to the 3D pine-like dendrites (metals characterized by medium j0 values). The appearing of a strong hydrogen evolution leads to formation of cauliflower-like and spongy-like forms (metals characterized by medium and low j0 values). The other disperse forms, such as regular and irregular crystals, granules, cobweb-like, filaments, mossy and boulders, usually feature metals characterized by the high j0 values. The globules and the carrot-like forms are a characteristic of metals with the medium j0 values. The very long needles were a product of molten salt electrolysis of magnesium nitrate hexahydrate. Depending on the shape of the disperse forms, i.e. whether they are formed without and with vigorous hydrogen evolution, formation of all disperse forms can be explained by either application of the general theory of disperse deposits formation or the concept of "effective overpotential". With the decrease of j0 value, the preferred orientation of the disperse forms changed from the strong (111) in the needle-like and the fern-like dendrites to randomly oriented crystallites in the 3D pine-like dendrites and the cauliflower-like and the spongy-like forms.


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