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

Abstract Fe-doped cerium oxide (CeO 2 ) hollow microspheres were successfully synthesized by a simple co-precipitation route using yeast as a bio-template and nitrate as the oxide precursor. The products were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, N 2 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 1.5–2.5 μm. The formation mechanism of Fe-doped CeO 2 hollow microspheres was proposed and discussed as well. The photocatalytic test results showed that the Fe-doped CeO 2 hollow microspheres exhibited a higher photocatalytic activity in the degradation of acid orange 7 (AO7) aqueous solutions containing H 2 O 2 under visible irradiation compared with CeO 2 hollow microspheres and Fe-doped CeO 2 nanoparticles, which was attributed to their more oxygen vacancies, higher specific surface area and lower band gap. The degradation rate of the Fe-doped CeO 2 hollow microspheres was found to be 93% after 80 min and the degradation reaction followed pseudo-first-order kinetics.