Abstract.Prussian Blue films were electrogenerated on the surface of the transparent ITO electrodes. The electrochemical oxidation to the Prussian Yellow form was investigated by means of in situ voltammetry and Vis-NIR spectroscopic techniques. Changes of the whole spectra between 400 and 950 nm were analyzed and three characteristic wavelengths were selected to in situ follow the electrochemical changes of the films.Voltammetric peaks and absorbance derivative curves at these three wavelengths were deconvoluted and were interpreted such as the overlapping of different electrochemical processes. The correlation between these overlapped processes has allowed proposing three different electrochemical processes for the interpretation of the whole electrochemical response. One of these processes corresponds to the oxidation of

Prussian Blue films were studied by in situ electrogravimetric and spectroelectrochemical methods during the electrochemical oxidation to the Prussian Yellow form. Spectroelectrochemical studies detected important absorbance changes during electrochemical experiments at 430 nm and 690 nm corresponding to the appearance of the yellow form and to the disappearance of the characteristic blue color. These changes of absorbance were well related with the voltammetric peaks. This redox process has also been studied by in situ electrochemical impedance spectroscopy, mass impedance and color impedance at 690 nm. It has been found that crossed impedance functions obtained from the original ones provide interesting information on the participation of both, cations and anions during electrochemical processes.