Dye-Sensitized Photocatalytic Hydrogen Production Promoted by Near-Infrared Pyrrolopyrrole Cyanine Sensitizers

The indispensable need for clean and sustainable energy sources has recently led to a deeper interest in dye-sensitized photocatalytic systems (DSPs) for hydrogen production. In this work, a pyrrolopyrrole cyanine (TB207) near-infrared photosensitizer is grafted over surface-platinized TiO2 nanoparticles for photocatalytic H2 evolution. Preliminary experiments deal with determining the optimal dye and Pt0 loadings as well as opportunely choosing the pH of the aqueous reaction medium. The resulting photocatalytic system exhibits about 400 turnover numbers (TONPS) in the presence of ascorbic acid at pH 4 after 6 h of irradiation with a sunlight simulator (1000 W/m2). At last, cosensitization of TB207 with eosin Y, a complementary visible light absorber, is tested both in dye-sensitized solar cells and DSPs, demonstrating an enhancement of the solar energy conversion performances of the cocktail dyes in both devices over the single absorber systems due to better light harvesting.