Research Of Hollow Microstructural Composite Oxides Prepared Via Yeast Templating Method

Hollow composite materials possess the characteristics such as lower density,higher surface area,bigger carrying capacity and other better properties which make it receives widespread attention.At present,the template method is the main method of preparing hollow composite materials.Compared with traditional templates,the biological template has become a potential research direction in synthesis of hollow materials due to the advantages of convenient operations,morphological diversity and environment friendly.In this paper,ATO hollow microspheres and Fe-doped CeO2 hollow microspheres were successfully synthesized by a simple co-precipitation route using yeast as a bio-template.The morphology and structure of the products were characterized by scanning electron microscope(SEM),X-ray diffraction(XRD),X-ray photoelectron spectrometer(XPS),Fourier transform infrared(FT-IR)and N2 adsorption-desorption isotherms(BET).The possible formation mechanisms of products were proposed,what's more,the near-infrared reflection performance of ATO hollow microspheres and the photocatalytic activity of Fe-doped CeO2 hollow microspheres were tested.The experimental results showed that the tetragonal rutile structure ATO hollow microspheres retain the ellipsoidal morphology of yeasts and had an average particle size of 2.0 ?m-3.0 ?m.Compared with ATO nanoparticles,ATO hollow microspheres possessed more Sb5+ and higher specific surface area of 73.5 In the infrared band of 850 nm-2000 nm,ATO hollow microspheres appeared widened infrared absorption phenomenon,the near-infrared reflection was obviously lower than ATO nanoparticles.In addition,the prepared Fe-doped CeO2 hollow microspheres also maintained the ellipsoidal morphology of yeasts with particle size ranging from 1.5 ?m?2.5 ?m.Compared with Fe-doped CeO2 nanoparticles and CeO2 hollow microspheres,Fe-doped CeO2 hollow microspheres possessed more oxygen vacancies,higher specific surface area and lower band gap.What's more,this paper also discussed the factors affecting the photocatalytic degradation of samples,such as:the order of addition of H2O2 and A07,different concentrations of Fe and H2O2,the type of sample.The results showed that when adding A07 and then adding H2O2,the mass of Fe(NO3)3 9H2O added was 1%of Ce(NO3)3·6H2O and the concentration of H2O2 was 1 mmol-L-1,the degradation rate of the Fe-doped CeO2 hollow microspheres was more than 93%under visible irradiation in 80 min.In sharp contrasty A07 degradation rate of only 64%and 81%was observed for degradation reaction catalyzed by Fe-doped CeO2 nanoparticles and CeO2 hollow microspheres as photocatalyst.