Carbon Electrodes In The Ferrous Thionine Photogalvanic Cell - A Quantitative Study Of Electrode Selectivity

The role of electrode selectivity in the performance of the ferrous/thionine photogalvanic cell has been studied using various carbon materials as light electrode. The open-circuit voltage of the cell is found to depend strongly on the type of carbon electrode used. This dependency can be quantitatively accounted for in terms of electrode kinetics. The leuco-thionine oxidation is about equally fast at all types of carbon electrode studied. Those electrodes that give rise to a high open-circuit voltage are selective owing to the suppression of the ferric reduction. This slow ferric/ferrous electron transfer has been related to the hydrophobicity of the electrode surface.