Synthesis of biomimetic cerium oxide by bean sprouts bio-template and its photocatalytic performance

Biomimetic nano CeO2 materials were prepared by using bean sprouts as bio-template through impregnation and thermal decomposition. For characterization of structure, X-ray diffraction spectroscopy （XRD）, field emission scanning electron microscopy （FESEM）, transmission electron microscopy （TEM）, UV-Vis diffuse reflectance spectra （UV-Vis/DRS） nitrogen adsorp- tion-desorption measurements and Labsolar H2 system were adopted. The results demonstrated that the samples prepared at 550 ℃ not only completely removed the original bio-template, but also retained the morphology and microstructure of bean sprouts. Then the biomorphic structure of fluorite structure CeO2 material was obtained. Micro-pores with a diameter of about 2-3 nm were distributed among the particles, which provided more favorable channel for the photocatalytic reaction. Biomimetic CeO2 materials exhibited clear red shift （50 nm） compared with powder CeO2, which could be excited by visible irradiation. Biomimetic CeO2 materials dis- played the superior photocatalytic activity for the hydrogen production by water splitting under the sunlight irradiation, the hydrogen yield could reach 400 ktmol/g catalyst after 6 h.