Challenging the [Ru(bpy)3]2+ Photosensitizer with a Triazatriangulenium Robust Organic Dye for Visible-Light-Driven Hydrogen Production in Water

Photosensitizers used in homogeneous photocatalytic systems for artificial photosynthesis, such as hydrogen production, are typically based on expensive transition metal complexes such as d6 ruthenium(II) or iridium(III). In this work, we demonstrate efficient H2 production in acidic water by using an organic dye derived from the triazatriangulenium (TATA+) family as a visible-light-absorbing photosensitizer (PS). By associating the hydrosoluble tris(ethoxyethanol)triazatriangulenium with an efficient H2-evolving cobalt catalyst and ascorbic acid as sacrificial electron donor (SD), remarkable photocatalytic performances were reached in aqueous solution at pH 4.5, under visible-light irradiation, with up to 8950 catalytic cycles versus catalyst. The performances of this dye largely exceed those of the benchmark Ru tris-bipyridine in the same experimental conditions when low concentrations of catalyst are used. This higher efficiency has been clearly ascribed to the remarkable robustness of the reduced form...