Cadmium ferrocyanide modifying layers on platinum electrodes are found to be polycrystalline by scanning electron microscopy and X-ray powder pattern analysis, with a typical crystallite size of 1 μm. Such layers are electroactive, with cation exchange at interstial lattice sites tightly coupled to charge transport processes. Charge transfer dynamics are affected by both the intrinsic mobility of interstial cations in the [CdFe(CN)6]2-/- surface overlayer and cation-induced structural reorganization of the overlayer. Energy dispersive X-ray analysis of interfaces which have undergone triangular wave potential cycling (cyclic voltammetric) in supporting electrolytes containing various alkali cations shows that, in general, these cations are exchanged into the surface lattice interstial (mobile) sites. One important exception is the case of a sodium nitrate containing electrolyte in which Cd2+ ions are found in a portion of these sites. This molecular configuration optimizes the observed charge transfer dynamics. A comparison of variations in powder pattern data as a function of potential cycling time (multiple cyclic voltammograms) shows specific correlations between structural changes and electrochemical reactivity.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Surfaces and Interfaces