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

Abstract

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 (Sm0.5Sr0.5CoO3 (SSC), La0.5Sr0.5CoO3 (LSC) and La0.5Sr0.5MnO3 (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.