Electrochemical and FTIR Spectroscopic Characterization of Ferrocyanide-Modified TiO Electrodes Designed for Efficient Photosensitization

摘要

The mechanism of the photosensitization of T1O2 by adsorbed ferrocyanide has been investigated by electrochemical measurements and surface FTIR spectroscopy. It is shown that surface roughness factors of approximately 100-200 are necessary for efficient light harvesting. Ferrocyanide adsorbates on titania are compared to TIFe(CN)6 films deposited by a novel electrochemical method onto metallic substrates. Cyclic voltammetry and analysis of the infrared vibrational spectra of TIO2-Fe(CN)4-6 surface complexes and TIFe(CN)6 indicate significant charge transfer from FeII to Ti VI. Ferrocyanide adsorption geometries are proposed on the basis of experimental data and geometric considerations of the anatase lattice. Light conversion efficiencies are discussed, and a model energy level diagram for the semiconductor/sensitizer/electrolyte interface is presented. Titanium dioxide. (mjm)