Auchynnikava, T. A.

Kulak, A. I.

Poznyak, S. K.

Rabchynski, S. M.

Streltsov, E. A.

English

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Inhibition effect of magnesium and calcium chloride additives  
on anodic chlorine evolution at platinum electrode  
in concentrated potassium chloride aqueous electrolytes 
Е. А. Streltsova, A. I. Kulakb, S. M. Rabchynskia, Т. A. Auchynnikavaa, S. K. Poznyakc  
a
Chemistry Department, Belarusian State University, Minsk, Belarus, e-mail: streltea@bsu.by 
b
Institute of General and Inorganic Chemistry, NAS of Belarus, Minsk, Belarus 
c
Research Institute for Physical Chemical Problems, Belarusian State University, Minsk, Belarus  
The effect of MgCl2 and CaCl2 additives on kinetic parameters of Cl
–
 anodic oxidation in 
an acidified KCl solution (pH 2) at platinum electrode with reduced (Ptred) and oxidized (Ptox) 
surface has been studied. Pretreatment of the electrode surface included 20-fold cycling of the 
electrode potential (E) from –0.3 to +1.6 V followed by its fixation at E = –0.3 V (Ptred) and +1.6 
V (Ptox). The addition of calcium and magnesium cations to 4 M KCl electrolyte was found to 
lead to 1.17 and 1.45-fold decrease in the exchange current (i0) at the Ptred electrode after 
replacement of the equivalent part of KCl to 1.24 M MgCl2 and 1.28 M CaCl2. Correspondingly, 
on the Ptox surface the addition of MgCl2 and CaCl2 results in 1.21 and 1.66-fold i0 drop. At the 
same time the coefficient b in Tafel equation increases from 55 to 68 mV at Ptred and from 47 to 
64 mV at Ptox in the presence of MgCl2, and does not change in CaCl2-containing electrolyte. 
The main reasons of the inhibition effect of MgCl2 and CaCl2 additives seem to be deviations of 
Сl– ion activity in an electric double layer and a specific adsorption of calcium and magnesium 
cations on the platinum surface. 
 
 
 
 
 


Inhibition effect of magnesium and calcium chloride additives on anodic chlorine evolution at platinum electrode in concentrated potassium chloride aqueous electrolytes

http://elib.bsu.by/bitstream/123456789/25793/1/Inhibition%20effect%20of%20magnesium%20and%20calcium%20chloride%20additives.pdf

Inhibition effect of magnesium and calcium chloride additives on anodic chlorine evolution at platinum electrode in concentrated potassium chloride aqueous electrolytes

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