Oxidation Reduction Potential of the Cu(3)/Cu(2) System in Alkaline Solutions

摘要

Potentials of barium and sodium cuprate coatings, obtained by an electrochemical method on platinum, and in isolated cases, on copper, were measured. It was shown that the stationary potentials were in the case of both cuprates. In 17-0.1 N Na0H solutions, the following dependencies were established: at 5 C, E = 0.77 to 0.52 lgaOH-, at 25 C E = 0.74 to 0.060 lgaOH-. In 10 to the -1 to 10 to the -3 N Na0H solutions, the slope slope coefficient for a linear dependence of the potential on pH is equal to (3/2) X (2.303RT/F). Upon addition of cuprite, the measured stationary potential complies with the dependence E = E1 - (2.303RT/F)lga ((c* sub) Cu(II) +(C sub) Cu(II) - (2.303RT/F)lgaOH-, where (c sub) Cu(II) is the concentration of the added divalent copper, and (c* sub) Cu(II) is the concentration of the species formed upon reduction of trivalent copper. Possible variations of potential determining reactions were discussed.