Double defects modified carbon nitride nanosheets with enhanced photocatalytic hydrogen evolution

Graphitic carbon nitride (g-C3N4) is an actively investigated metal-free photocatalyst for solar energy conversion. However, primary g-C3N4 usually exhibits limited utilization of visible light and fast combination of photoexcited charge carriers, resulting in low photocatalytic H-2 evolution activity. Defect-modified g-C3N4 shows much enhanced photocatalytic H-2 evolution activity owing to extended light absorption as well as efficient charge separation and transfer. Here, the photocatalyst simultaneously containing nitrogen vacancies and O-doping is successfully developed by using a two-step post-synthetic strategy for photocatalytic H-2 evolution, resulting in a greatly-boosted H-2 evolution activity (1.69 x 10(3) mol g(-1) h(-1)) compared with that of pristine g-C3N4 (1.12 x 10(2) mol g(-1) h(-1)). It is believed that the newly developed double-defect strategy may open an avenue toward obtaining molecular level comprehension of the function of a catalyst in photocatalytic H-2 evolution and can be extended to the modification of other semiconductors.