Hydrothermal synthesis of graphene-ZnTiO3 nanocomposites with enhanced photocatalytic activities

Abstract

Pure phase ZnTiO3 was prepared through a sol–gel process, then graphene-ZnTiO3 nanocomposites were synthesized by a hydrothermal method using the prepared ZnTiO3 nanoparticles and graphene oxide as precursors. X-ray diffraction results revealed the production of pure cubic ZnTiO3 at 600 °C. ZnTiO3 was anchored on the graphene nanosheets, demonstrating a spherical morphology in transmission electron microscope images. The existence of chemical bond Ti–O–C in the nanocomposites was proved by Fourier-transforming infrared spectroscopy. UV–Vis diffusive reflection spectra indicated that the absorption edge of the nanocomposites shifted towards the visible region. The photocatalytic activity of the composites was tested through the photocatalytic degradation of methyl blue under simulated solar irradiation. The results showed that the photocatalytic activity of the nanocomposites was obviously increased in contrast to pure ZnTiO3, which was strongly affected by the crystalline structure of ZnTiO3 and the concentration of graphene. The enhanced photocatalytic activity was mainly attributed to the conglomeration inhibition of ZnTiO3 nanoparticles, the electron transfer between ZnTiO3 and graphene and the extended absorption range. Furthermore, other contaminants such as tetracycline, Rhodamine B and methyl orange were tested under the same conditions to investigate the photocatalytic performance of the photocatalysts. The reusability tests indicated that the prepared composites exhibited good stability.