Constructing an S-scheme Fe2O3/MnS heterojunction for efficient photocatalytic H2 evolution in visible light

Abstract

A series of S-scheme Fe₂O₃/MnS heterojunction composites have been successfully fabricated through the hydrothermal method by loading Fe₂O₃ onto the surface of MnS. The XRD demonstrates that the crystalline structure of MnS remains unaltered after loading with Fe₂O₃. SEM and TEM tests revealed that Fe₂O₃ is uniformly loaded on the MnS surface and tightly bound to it, forming a high-quality S-scheme heterojunction. Moreover, XPS analysis and work function theory data imply that an internal electric field (IEF) is generated at the interface between Fe₂O₃ and MnS. Moreover, the IEF not only effectively boosts the separation and transfer of carriers but also greatly preserves the powerful reducing property of MnS conduction band electrons and the strong oxidation property of Fe₂O₃ valence band holes. The outcomes of hydrogen production by water splitting tests show that the Fe₂O₃/MnS composite has better hydrogen production performance than pure MnS and Fe₂O₃. When the loading amount of Fe₂O₃ reaches 6 wt%, the photolytic hydrogen production rate of the Fe₂O₃/MnS attains its optimal level, approximately 1075 μmol·g⁻¹·h⁻¹, which is approximately 4.7 times that of MnS and 3.2 times that of Fe₂O₃, respectively. After four cycles, the hydrogen production capacity of Fe₂O₃/MnS do not show a significant decrease, indicating the favorable reusability of the Fe₂O₃/MnS composite catalyst.