Simultaneous triple-effect on inhibiting the photogenerated carriers recombination of g-C₃N₄ for boosting solar H₂ production at atmospheric pressure

Graphitic carbon nitride (g-C₃N₄) has been well known as one of the important organic semiconductor photocatalyst. However, its low photocatalytic activity greatly hampered its application, which relates to it fast recombination of photoexcited electrons and holes. In this work, conductive thermal oxidation catalysts with good photothermal property (Sm_0.5Sr_0.5CoO₃ (SSC), La_0.5Sr_0.5CoO₃ (LSC) and La_0.5Sr_0.5MnO₃ (LSM)) were used to construct few-layer g-C₃N₄ based photocatalysts with simultaneously triple-effect on inhibiting the photogenerated carriers recombination. The stacking of g-C₃N₄ can be reduced by the thermal oxidation and the thickness of few-layer g-C₃N₄ nanosheets is about 1.5 nm on average, which shortens the migration distance of electrons. The heat converted by the photothermal effect of SSC can accelerate the migration of photogenerated electrons. In addition, the consumption of photogenerated holes can be transferred from g-C₃N₄ to SSC, further restraining the recombination of electron-hole pairs. The prepared few-layer g-C₃N₄ nanosheets with 1% addition of SSC exhibit a superior hydrogen evolution rate of 16,521.4 μmol g⁻¹ h⁻¹, which is 13.2 times higher than that of the bulk g-C₃N₄ at atmospheric pressure.