| ZnO nanomaterials have been widely applied to water treatment,environmental purification,coating material,solar cell,etc.,due to the unique photoelectric properties of ZnO.However,difficult recycling and easy agglomeration seriously limited the practical applications of ZnO photocatalysts.The flower-like ZnO nanostructures possess many advantages,such as large size,low friction,good dispersion and more reaction sites.Unfortunately,pure flower-like ZnO still suffers from some drawbacks of low separation rate of photogenerated electron-hole pairs and narrow spectral response range,which leads to weak photocatalytic activity under natural sunlight.In order to simplify the prepared process and achieve the spectrum response of ZnO materials to visible-light,a low-temperature hydrothermal method was used to synthesis the flower-like ZnO nanostructures in this work.Using zinc nitrate hexahydrate,sodium hydroxide and cetyltrimethylammonium bromide as raw materials,and deionized water as a solvent.Moreover,graphene(GO),molybdenum sulfide quantum dots(MoS2 QDs)and stannous oxide(SnO)were used to modify ZnO for improving its light absorption capacity and separation rate of photogenerated electrons-holes.The X-ray diffraction(XRD),Scanning electron microscope(SEM),Transmission electron microscope(TEM),Raman spectrum and X-ray photoelectron spectroscopy(XPS)were used to investigate the effects of each component proportion on the morphology and structure of flower-like ZnO.Moreover,the optical performance of obtained samples was characterized,such as UV-vis,PL and photocurrent spectrum.The photocatalytic activity of as-prepared samples was tested under natural sunlight and dark,and the enhancement mechanism of ZnO was analyzed in this work.The main findings of this paper are as follows:(1)The flower-like GO/ZnO composite was successfully prepared by hydrothermal method at 90? The introduction of graphene did not change the flower-like ZnO nanostructures,and increased its light absorption ability and electrons-holes separation.At the same time,the high photocatalytic activity and large capacitance of ZnO can be ascribed to excellent electrical properties and special structure of graphene.The optimal sample can degrade rhodamine B completely within 120 mins under natural sunlight irradiation when the mass ratio of GO to ZnO is 0.37%.Moreover,the degradation efficiency of flower-like GO/ZnO composite was still above 95%after 5 cycles of experiment.(2)The flower-like MoS2 QDs/ZnO with,particle size about 1.2-2.1 ?m were obtained via hydrothermal method at low temperature.The introduction of MoS2 QDs can expand the the spectral response range of flower-like ZnO nanostructure to sunlight.Meanwhile,the"synergistic effect" formed betweeen MoS2 and ZnO increased the separation rate of photo-generated carrier of ZnO,and further enhanced its photocatalytic performance.0.11 wt%MoS2 QDs in ZnO showed best photocatalytic activity,which degraded completely rhodamine B within 90 mins and manifested good stability after 5 cycles of stability.In addition,the special electrical properties and unique internal structure of MoS2 endowed ZnO with degrading ability in the dark.(3)The flower-like SnO/ZnO nanostructures with high activity,good stability and light memory ability were successfully obtained by hydrothermal method.The incorporation of SnO improved the absorption ability of ZnO for visible-light and enhanced the separation rate of photogenerated electrons-holes because of formed the "synergistic effect" between SnO and ZnO.Moreover,the optimal sample(SnO:ZnO at 12.7%)degraded RhB within 60 minutes.The degradation rate of SnO/ZnO still keeps 97%after 5 cycles of photocatalytic experiment.In addition,ZnO exhibited high degrading efficiency in the dark due to the special atomic structure and excellent electrical properties of SnO. |
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