Oxygen electrode reversibility in ionic melts

Part 4. Oxygen Electrode Reversibility in Ionic Melts 

We have repeatedly emphasized that the most reliable data on Lux acid-base interactions taking place in ionic melts can be obtained using the potentiometric method, which provides detection of the equilibrium oxide-ion concentrations over wide pO ranges. These investigations imply the use of indicator electrodes reversible to O2- in cells with the liquid junction. Literature sources contain much information devoted to studies of the features of reversibility of the following kinds of oxygen electrodes  

As mentioned earlier, investigations of the oxygen electrode operation in different ionic melts are numerous. The reversibility of the oxygen electrode is reported practically in every paper concerned with the study of Lux acid-base interactions in ionic melts. 

Gas oxygen electrodes [Pt(02) being the most widely used] are often exploited for the investigations of oxide-ion chemistry in most nitrate, chloride and sulphate melts. The construction of this kind of electrode is simple enough [62] they are made of a noble (or in a more general case, inconsumable) metal plate (Au, Pt, Ag, Pd), placed in an atmosphere with a definite, known constant partial pressure of 02 and partially immersed in the studied melt containing oxide ions. 

It is generally accepted that at the gas oxygen electrode there takes place a process of reduction of gaseous oxygen with the transfer of two electrons per 

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