▎ 摘　　要

The charge transfer between hydrogen evolution photocatalysts (HEPs) and oxygen evolution photocatalysts (OEPs) is the rate-determining step that controls the overall performance of a Z-scheme water-splitting system. Here, we carefully design reduced graphene oxide (RGO) nanosheets for use as solid-state mediators to accelerate the charge carrier transfer between HEPs (e.g., polymeric carbon nitride (PCN)) and OEPs (e.g., Fe2O3), thus achieving efficient overall water splitting. The important role of RGO could also be further proven in other PCN-based Z-systems (BiVO4/RGO/PCN and WO3/RGO/PCN), illustrating the universality of this strategy.