Abstract
Graphitic carbon nitride (g-C
3
N
4
) is an actively investigated metal-free photocatalyst for solar energy conversion. However, primary g-C
3
N
4
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-C
3
N
4
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 × 10
3
μmol g
−1
h
−1
) compared with that of pristine g-C
3
N
4
(1.12 × 10
2
μmol 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.