An in situ UV-Vis spectroelectrochemical investigation of the dichromate reduction at a polyaniline-modified electrode

The electroreduction of dichromate at polyaniline (PANI) modified ITO glass electrodes in acidic solution was investigated with in situ UV-Vis spectroelectrochemistry. It has been shown that under open circuit conditions dichromate does irreversibly oxidise the PANI layer. Under controlled potential conditions cathodic reduction of dichromate was shown to proceed at PANI-modified electrodes. The overall rate of dichromate reduction was shown to be independent on the electrode potential of the PANI-modified electrode in the range of E-RHE=+0.2 to +0.8 V. From the data obtained it was concluded that a redox reaction between dichromate and PANI is the rate-determining step of the overall electrocatalytic process.