Superior photocatalytic performance of LaFeO3/g-C3N4 heterojunction nanocomposites under visible light irradiation

Abstract

New types of LaFeO₃/g-C₃N₄ heterostructures were successfully prepared and the enhanced photocatalytic hydrogen evolution and degradation activities under visible light irradiation were determined. They possessed the features of a Z-scheme photocatalysis system. The photoexcited electrons on the conduction band of LaFeO₃ were transferred to the valence band of g-C₃N₄ by the solid–solid intimately contacted interfaces, where the electrons and holes were recombined, and thus improved the separation of photogenerated electrons and holes of g-C₃N₄. The LaFeO₃/g-C₃N₄ heterostructures showed a higher hydrogen evolution rate and a higher amount of ˙OH than pure LaFeO₃ and g-C₃N₄. The construction of the LaFeO₃/g-C₃N₄ heterostructures was used to demonstrate an effective strategy for improving the photocatalytic property. The 5%-LaFeO₃/g-C₃N₄ exhibited the highest photodegradation and water splitting rate. More than 95% of methylene blue (MB) was degraded after 15 min in the presence of 25 mg EDTA-2Na in 100 mL MB solution which was irradiated using a 3 W light-emitting diode. The 5%-LaFeO₃/g-C₃N₄ heterojunction nanocomposite had a maximum hydrogen evolution rate of 158 μmol g⁻¹ h⁻¹.