In-situ external reflection FTIR spectroelectrochemical and XPS investigations of cobalt-cyanometallates as inorganic polymeric materials on a platinum electrode

Cobalt-cyanometallate films electrochemically deposited on a platinum elect rode were studied by cyclic voltammetry (CV), in-situ FTIR spectroelectroch emistry (FTIRs) and potential resolved XPS measurements. The experimental r esults reveal that the CoHCF film on Pt electrode exists in two forms. The major form of the inner layer of the film is (M+)(2)Co(II)Fe(II)(CN)(6) whe re M+ denotes a cationic counter ion, in which both the Fe2+ and Co2+ cente rs can be oxidized to Fe3+ and Co3+ in the potential range of 0-1.0 V vs. A g/AgCl in NaCl solution. The major form of the outer layer is Co(II)(2)Fe(I I)(CN)(6) in which electrochemical reactions in this potential range an lim ited by kinetic sluggishness. The FTIR and XPS spectra indicated that the C o centers change from high-spin state to low-spin state accompanying the Co 2+/Co3+ oxidation reaction. In addition, the cations' effect on electrochem ical reactions of CoHCF is also discussed. (C) 1999 Elsevier Science B.V. A ll rights reserved.