Prussian Blue films were investigated by using ac-electrogravimetry, that is, simultaneous impedance and electrogravimetry spectroscopies at different potentials between the totally reduced form, Everitt's salt, and the mixed-valence compound, Prussian Blue, in KCl solutions. Experimental results allow clear information on the role played by the different ions that are present in the solution to be obtained. It was found that when the film was reduced potassium ions enter the film whereas these are protons that enter at potentials more anodic than the formal potential of the redox process in KCl solutions. It was also proved that potassium ions enter the PB film without water.

Hydrogen absorption into palladium thin films ͑10 monolayers and 100 m͒ was studied using cyclic voltammetry. The behavior of thin layers prepared by electrodeposition is different from that of the bulk Pd. On very thin films hydrogen adsorption, absorption, and evolution processes are separated. Adsorption kinetics depends strongly on applied potential and layer thickness. A new method is proposed for the determination of the quantity of adsorbed hydrogen in the presence of the absorption process.

This paper develops a framework for the interpretation of ionic insertion/deinsertion reactions in an aqueous environment taking place in transition-metal hexacyanoferrates of the general formula K(h)[Fe(2+) (CN)(6)](l).mH(2)O, also called Prussian Blue. Three different processes were fully separated in the electrochemistry of these films. It was clearly identified that one of these electrochemical processes involves the insertion/deinsertion of H(3)O(+) (hydrated protons) through the channels of the K(h)[Fe(2+) (CN)(6)](l).mH(2)O structure to reach the film electroneutrality during the electron transfer between Everitt's Salt and Prussian Blue. The other electrochemical processes involve K(+) or H(+) (proton) exchange through the water crystalline structure existing in the channels of the K(h)[Fe(2+)(CN)(6)](l).mH(2)O structure.