Research Of Hollow Microstructural Oxides And Composite Oxides Prepared Via Pollen Templating Merhod

Composite semiconductors with special morphologies have attracted wide attention from scholars at home and abroad due to their advantages of large specific surface area,small relative density and strong capacity.Template method is the main way to make oxides with special morphology.Among many templates,biological templates have been gradually applied to synthesize various morphologies of semiconductor oxides due to their economic benefits,regular morphology,variety and green environmental protection.In this experiment,ZrO2 hollow microspheres and ZrO2-TiO2 spinous hollow microspheres were synthesized by microwave solvothermal method and solvothermal method using pollen as biological template.The morphology,crystal structure and specific surface area of the samples were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),X-ray photoelectron spectrometer(XPS),Fourier transform infrared spectroscopy(FT-IR),nitrogen adsorption-desorption isotherms(BET),ultraviolet-visible diffuse reflection(UV-Vis).The formation mechanism of oxide with special morphology was analyzed.The adsorption properties of ZrO2 hollow microspheres and the photocatalytic properties of ZrO2-TiO2 spinous hollow microspheres were discussed.The experimental results showed that different morphologies of ZrO2 hollow microspheres could be obtained by treating rape pollen with different methods.The scale-like wall hollow ZrO2 microspheres prepared by using rape pollen as template were about 20 ?m in length and 8-10 ?m in width.Porous ZrO2 hollow microspheres were synthesized using the pollen wall etched by hydrochloric acid as template.The diameter of the microspheres was about 12-14 ?m.Compared with ZrO2 micro-nanoparticles and scale-like wall hollow ZrO2 microspheres,the porous ZrO2 hollow microspheres have high specific surface area and good adsorption performance,the specific surface area is 40.9 m2/g,and the adsorption performance of Congo red dye reaches 96.98 m2·g-1.The adsorption process of all samples conforms to pseudo-second-order kinetic equation,and the adsorption isotherm follows Langmuir isotherm model,which indicates that the adsorption processwas homogeneous adsorption of monolayer.The diameter of TiO2 spinous hollow microspheres and ZrO2-TiO2 spinous hollow microspheres synthesized by solvothermal method using sunflower pollen as template is about 12-15?m.Compared with TiO2 spinous hollow and ZrO2 micro-nanoparticles,ZrO2-TiO2 spinous hollow microspheres have smaller crystallite size and higher specific surface area.At the same time,the effect of the amount of ZrO2 on the photocatalytic performance of ZrO2-TiO2 spinous hollow microspheres was also discussed.The results of photocatalytic activity showed that the prepared ZrO2-TiO2 spinous hollow microspheres had excellent photocatalytic performance,and the degradation rate of Rhodamine B solution at 10 mg/L could reach 96.3%within 60 min.It was significantly higher than that of TiO2 spinous hollow microspheres(65.7%)and ZrO2-TiO2 micro-nanoparticles(76.6%)and the photocatalytic degradation process of all samples conforms to pseudo-first-order kinetic equatio.In addition,the photocatalytic properties of ZrO2-TiO2 spinous hollow microspheres at different pH values show that the products have good acid and alkali resistance.Radicals trapping experiments show that the main active species in photocatalytic process are hydroxyl radical(·OH),oxygen anion radical(·O2-)and holes(h+).