Visible light induced efficient hydrogen production through semiconductor-conductor-semiconductor (S-C-S) interfaces formed between g-C<inf>3</inf>N<inf>4</inf> and rGO/Fe<inf>2</inf>O<inf>3</inf> core-shell composites

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.