Photogalvanic cells based on the photoreduction of xanthene dyes using riboflavin as a sensitizer in aqueous/micellar medium

Abstract

The photochemical reduction of fluorescein, eosin (Y) and rosebengal by disodium salt of EDTA using riboflavin (B₂) as a sensitizer has been studied in aqueous, neutral (triton X-100) and cationic (CTPB) micellar media. The two micelles (i.e. neutral and cationic) are found to catalyse the electron transfer from reduced riboflavin to the dye in the forward photoreaction. Oxidation of semi-reduced dye radical (DH) at the anode (Pt electrode) in a two-compartment photogalvanic (PG) cell which contains riboflavin, Na₂EDTA and dye (D) in the photoanode compartment and 1.0 <em>M </em>HClO₄ in the dark cathode compartment generates noticeable photocurrents. Remarkable increase in photocurrent is noticed in the micellar medium compared to that in the aqueous medium. The stability of the cell also increases in micellar medium.