Superior Photocatalytic Generation of H2 in Water Medium Through Grafting a Cobalt Molecule Co-Catalyst from Carbon Nitride Nanosheets

Graphical Let the sun shine ! Photocatalytic hydrogen evolution is an attractive way to convert sunlight to fuel for solving worldwide energy shortage and environment issues. This study demonstrates non-noble photocatalysts consisting cobalt complex and graphitic carbon nitride, in which CoL 2 (SCN) 2 cocatalyst was covalently grafted onto CN. This hybrid exhibits excellent performance towards photocatalytic H 2 generation (272 μmol g −1 h −1 ) from water medium and also presents high stability, which provides a novel way for designing high activity and low-cost photocatalysts for solar H 2 conversion. To develop stable, efficient, non-noble metal-based photocatalysts for water splitting has become a long-standing challenge. Here, cobalt−phenanthroline active species are grafted from metal-free photosensitive carbon nitride nanosheets (CN) by dehydration reaction between pendant amino groups from CN and carboxyl groups of functional phenanthroline ligands for photocatalytic H 2 evolution in water medium. The cobalt complex unit serves as a cocatalyst to accelerate separation and transferring of photoexcited charge carriers, and reduce overpotential for H 2 evolution. The hybrid catalyst without any precious metals exhibits excellent performance of H 2 evolution (272 μmol g −1 h −1 ) and high stability during photocatalytic reaction. The finding not only develops a facile way to prepare high-performance low-cost photocatalysts for photocatalytic H 2 production, but also provides a new insight into optimizing the interface between cocatalysts and photosensitizers for photocatalytic reaction by grafting active sites directly from semiconductors.