Structural characterization and photocatalytic activity of electrospun TiO_2 and Ce-doped TiO_2 nanofibers

摘要

Mixed phase TiO_2 and Ce-doped TiO_2 nanofibers with different content (0.5, 2.0, 8.0%) of cerium ions were prepared by a sol-gel electro-spinning method. Results from SEM showed no beads on the undoped-TiO_2 and Ce-doped TiO_2 nanofibers with diameters in the range of 77-130 nm. TEM images exhibited that the undoped TiO_2 crystallite size on the fiber was bigger than those on the Ce-doped samples. XRD and Ti K-edge XANES were used to determine anatase/rutile phase ratios in pure TiO_2 nanofibers, whereas only XANES was used to characterize the anatase/rutile phase ratios in the Ce-doped TiO_2 samples. Ce L_3-edge XANES exhibited peak associated with Ce~(+3) (5727 eV.) in addition to Ce~(+4) (5731 and 5738 eV.). Samples with the lowest Ce content had the greatest fraction of Ce ions in the Ce~(+3) state. The photocatalytic activity of the prepared nanofibers was observed by degradation of Rhodamine B under visible light, and the fiber of 0.5 % Ce-doped TiO_2 exhibited the highest activity.