Protonated Graphitic Carbon Nitride with Surface Attached Molecule as Hole Relay for Efficient Photocatalytic O2 Evolution

Carbon nitride has been considered as one of the most promising materials to catalyze O2 evolution from water; however, its intrinsic drawbacks of surficial inertness and poor charge separation efficiency are serious. In contrast to the ordinary modification method of cocatalyst loading, we describe here that a simple modification method of molecule loading can greatly improve the activity of carbon nitride for O2 evolution. A mechanistic investigation by time-resolved transient absorption spectroscopy reveals that the BODIPY molecule can extract photogenerated holes in carbon nitride to promote the oxidation of water. It is the first case of a dye molecule acting as a hole relay to promote photocatalytic water oxidation. These results provide a new approach to the modification for the better catalytic performance of carbon nitride on O2 evolution.