| The electrochemistry of the Ce(IV)/Ce(III) redox couple was investigated as a function of working electrode composition and solution environment. Optimum redox couple resolution in aqueous sulfuric acid was achieved at an acid concentration of 0.1 M. A decline in redox couple resolution and reversibility was observed as acid concentration was increased to 2.0 M. The influence of pH was illustrated using sulfate solutions of increasing pH and constant ionic strength. Results indicated that a pH greater than 2 was detrimental to redox couple resolution. The glassy carbon electrode provided the widest potential window and was least affected by changes in pH. Studies were conducted in aqueous NTA, citrate, and EDTA, but redox couple resolution was successful only at the Pt electrode in EDTA. Complexation with EDTA resolved cerium electrochemistry from background currents by shifting the redox couple to less positive potentials, and allowed its observation across a wide pH range. |
