Novel preparation of high-yield graphene and graphene/ZnO composite

In this paper, high-yield graphene (GRZ) and visible light-driven photocatalyst graphene/ZnO (GR/ZnO) composite were efficiently prepared by combining ball-milling and liquid-phase exfoliation (LPE) under mild conditions, in which ZnO-PVA (ZnO modified by polyvinyl alcohol) played a crucial intensification role. The addition of ZnO-PVA in ball-milling process could increase the yield of graphene from 16.7% to 32.9% compared with that without ZnO-PVA. High yield of graphene, obtaining GR/ZnO composite conveniently along with the ease of ZnO-PVA particles removal from graphene solution are the unique features of this approach. A series of characterizations such as UV–vis, SEM, TEM, EDS , XRD , Raman, XPS, EIS were carried out to explore the structure, morphology and characteristics of graphene and GR/ZnO composite, as well as the exfoliation mechanism of graphite and photocatalytic mechanism of GR/ZnO. Moreover, the as-prepared GR/ZnO showed significantly enhanced photocatalytic activity under simulated sunlight irradiation, in which 74.3% of methylene blue (MB) and 95.5% of Rhodamine B (RhB) was decomposed after 180 min. The relatively low-cost, simple and efficient preparation method of graphene and GR/ZnO composite is promising for large-scale application.