Influence of chemisorbed carbon monoxide on hydrogen evolution at smooth platinum electrodes in sulfuric acid solution

1980 ◽  
Vol 115 (1) ◽  
pp. 45-51 ◽  
Author(s):  
M.W. Breiter
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.


Author(s):  
V.V. Tretyakova ◽  
◽  
A.E. Ponomareva ◽  
V.V. Panteleeva ◽  
А.B. Shein ◽  
...  

The phase composition and structure of titanium silicide have been investigated by X-ray diffraction and X-ray spectral microanalysis methods. It has been found that the investigated silicide is a singlephase system consisting of a high-temperature TiSi2 modification with a rhombic face-centered lattice. The cathodic behavior of the TiSi2 electrode has been studied by the methods of polarization and capacitance measurements. It has been found that the cathodic potentiostatic curves of silicide in solutions of 0,5 M H2SO4; 0,5 M H2SO4 + 0,005 M NaF and1,0 M NaOHhave Tafel sections with slopes of 0,120; 0,097 and 0,109 V and they are characterized by the values of the hydrogen evolution overvoltage 0,90; 0,64 and 0,74 V (at i = 1 A/cm2), respectively. Titanium disilicide in sulfuric acid solution belongs to materials with a high overvoltage of hydrogen evolution, but in a fluoride-containing sulfuric acid solution and in an alkaline solution - to materials with a low overvoltage of hydrogen evolution. Based on measurements of the differential capacitance of the TiSi2 electrode (at f = 10 kHz), it has been concluded that a thin silicon dioxide film (Si + 2H2O → SiO2 + 4H+ + 4e–)is present on the surface of the silicide in the acidic fluoride-free electrolyte.


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