Carbon dots for photocatalytic H2 production in aqueous media with molecular Co catalysts

Carbon dots and nitrogen doped carbon dots were effectively synthesized and characterized. Their use as light harvesters was examined in the presence of three different cobalt-based catalysts and tris(carboxyethyl)phosphine/ascorbic acid (TCEP/Asc), as the sacrificial electron donor (SED). The electrons are transferred from the valence band (VB) to the conduction band (CB) of the carbon dots and the holes that are formed are filled by electrons transferred from the SED. The best photocatalytic system reported herein produces 17.1 μmol of H2 (TONCAT = 859) under UV radiation for 52 h. The same system can produce 5.3 μmol of H2 (TONCAT = 264) under the Cretan sun for 21 days of solar irradiation.