Visible light induced efficient hydrogen production through semiconductor–conductor–semiconductor (S–C–S) interfaces formed between g-C3N4 and rGO/Fe2O3 core–shell composites

Abstract

Herein, we have constructed a type II heterojunction, g-C₃N₄ supported rGO/Fe₂O₃ core–shell composite, using a sonochemically assisted hydrothermal method followed by a wet-impregnation method for visible light driven hydrogen production via water splitting. Notably, compared to pristine g-C₃N₄ (432.4 μmol g⁻¹ h⁻¹) and g-C₃N₄/rGO (876 μmol g⁻¹ h⁻¹), we have achieved ∼15 and 7.5 fold enhanced photocatalytic H₂ production rates with g-C₃N₄/rGO/Fe₂O₃ (6607 μmol g⁻¹ h⁻¹) composites. The improved photocatalytic H₂ production performance was mainly attributed to the formation of type II heterojunctions between g-C₃N₄ and Fe₂O₃ mediated through rGO by forming Fe–O–C and C–N–C bonds as confirmed by XPS analysis. Moreover, the photo-generated carriers are rapidly separated through the electron mediator rGO via the Z-scheme mechanism as is consistent with PL, EIS and photocurrent studies.