Polymer solution-assisted assembly of hierarchically nanostructured ZnO onto 2D neat graphene sheets with excellent photocatalytic performance

Abstract Neat graphene (NG) is rarely selected as a support to improve the photocatalytic performance of metal oxides. Herein, an in-situ assembly of hierarchical ZnO nanoflowers with NG sheets was developed to fabricate ZnO/graphene nanohybids in the assistance of poly (2-acrylamido-2-methyl-1-propanesulfonic acid) solution. XRD, Raman, XPS, DRS, SEM, TEM and N2 adsorption-desorption analyses were performed to characterize the structure and composition of ZnO/graphene. The formation of Zn–O–C bond was evidenced between the interfaces. The incorporation of graphene slightly narrowed the bandgap of ZnO semiconductor, but significantly enhanced the light absorption in the visible range. Photoreduction of Cr(VI) exhibited that ZnO/graphene offered excellent photoactivity under both UV and visible light. NG as an electron transporter promoted the separation of photogenerated carriers and thus, the photoactivity of ZnO/graphene was improved. Under UV irradiation, bandgap-excited ZnO and excited-state graphene attended the photoreduction of Cr(VI) together, while under visible light the electrons injected into the CB of ZnO from the excited graphene were the origin of the photoactivity. The photocorrosion suppression was also confirmed. The present work provided a simple and practical method to prepare ZnO/graphene nanohybrids with NG as feedstocks. The nanohybrids showed efficient and stable photocatalytic performance for water pollution remediation.