Improved photocatalytic performance of N-doped ZnO/graphene/ZnO sandwich composites

Sandwich-type hybrid consisting of N-doped ZnO/N-doped graphene/ N-doped ZnO (NZ/NG/NZ) is fabricated via solution reaction and subsequent carbonization using oligoaniline and graphene oxide (GO) as precursors mixed with zinc acetate solution. Oligoaniline serves as a spacer material by participating in the π-π interaction with GO nanosheets and prevents their restacking. The oligoaniline coordinates with Zn 2+ ions and along with carbonization, it results in a sandwich-type structure of N-doped ZnO/graphene/ZnO composite. The obtained N-doped ZnO/graphene/ZnO composite showed an excellent photocatalytic performance. Remarkably, the sandwich-type structure provides plenty of active sites in which N-doped ZnO has the narrowed bandgap with a visible light response and the N-doped carbon matrix facilitates effective photoinduced electron-hole separation. The strategy presented here offers an effective method to prepare such sandwich-structured N-doped metal oxide/graphene composites for photocatalysis or energy storage.