Yeast-template synthesized Fe-doped cerium oxide hollow microspheres for visible photodegradation of acid orange 7.

Fe-doped cerium oxide (CeO2) hollow microspheres were successfully synthesized by a simple co-precipitation route using yeast asa bio-template and nitrate as the oxide precursor. The products were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, N2 adsorption-desorption isotherms and UV-Vis diffuse reflectance spectroscopy. It was found that the products had a well-defined ellipsoidal morphology and the size of the hollow microspheres was about 1.5-2.5μm. The formation mechanism of Fe-doped CeO2 hollow microspheres was proposed and discussed as well. The photocatalytic test results showed that the Fe-doped CeO2 hollow microspheres exhibited a higher photocatalytic activity in the degradation of acid orange 7 (AO7) aqueous solutions containing H2O2 under visible irradiation compared with CeO2 hollow microspheres and Fe-doped CeO2 nanoparticles, which was attributed to their more oxygen vacancies, higher specific surface area and lower band gap. The degradation rate of the Fe-doped CeO2 hollow microspheres was found to be 93% after 80min and the degradation reaction followed pseudo-first-order kinetics.