Double defects modified carbon nitride nanosheets with enhanced photocatalytic hydrogen evolution

Abstract

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 H₂ evolution activity. Defect-modified g-C₃N₄ shows much enhanced photocatalytic H₂ 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 H₂ evolution, resulting in a greatly-boosted H₂ evolution activity (1.69 × 10³ μmol g⁻¹ h⁻¹) compared with that of pristine g-C₃N₄ (1.12 × 10² 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 H₂ evolution and can be extended to the modification of other semiconductors.