Artificial all-solid-state system by RGO bridged Cu2O and Bi2WO6 for Z-scheme H2 production and tetracycline degradation

With the development of visible-light-driven photocatalytic systems, the Z-scheme system has been paid more attention for water-splitting and contaminants degradation in an effort to the full utilization of superior band potential between two different semiconductors. Here we present systemic investigation of the reduced graphene oxide (RGO)-based composites, including RGO-Cu2O, RGO-Bi2WO6, RGO-Cu2O/Bi2WO6, Cu2O/Bi2WO6 heterojunction and physical mixed RGO + Cu2O + Bi2WO6, to give a clear demonstration of the Z-scheme photocatalytic mechanism. The three-component RGO-Cu2O/Bi2WO6 composite showed the highest photocatalytic activity on water splitting, which is about 3 times and 4 times that of RGO-Cu2O and Cu2O respectively. And it also exhibited an excellent photocatalytic performance with a 86% degradation rate for tetracycline that is about 3 (6) times as high as that of pure Cu2O (Bi2WO6). These results demonstrate that the construction of RGO-Cu2O/Bi2WO6 Z-scheme system is beneficial to water splitting and pollutant degradation for which the superior band potential of Cu2O and Bi2WO6 are fully utilized. This work not only reports a new Z-scheme system of RGO-Cu2O/Bi2WO6 but also provides a guide to the design of RGO-based photocatalysts.