Synthesis, characterization and high natural sunlight photocatalytic performance of cobalt doped TiO2 nanofibers

Co2+ doped TiO2 nanofibers with different doping percentages were successfully synthesized using a nonaqueous sol-gel method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), x-ray photoelectrons spectroscopy (XPS), FTIR and UV-vis spectroscopy were used to characterize the crystal structures, chemical states, morphologies and photocatalytic properties of Co doped TiO2 nanofibers. Co2+ doping was found to affect the phase transformation from anatase to rutile. Grain growth activation energy of 17.575 kJ/mol was obtained for the TiO2 nanofibers. The photocatalytic activities of the pure and doped nanofibers were investigated with degradation of methyl orange (MO) as a model pollutant. The degradation followed the Langmuir-Hinshelwood CL-H) kinetic model with pseudo-first-order apparent rates of 3.2 x 10(-2), 5.3 x 10(-2), 8.9 x 10(-2) and 7.1 x 10(-2) for Co doped nanofibers of R-t=0.0, 0.0025, 0.005, 0.01 (where R-t is the molar ratio of Co(OAc)(2) to Ti((OPr)-Pr-i)(4)). The result showed that Co2+ doped nanostructure significantly enhanced the photocatalytic degradation of methyl orange under direct sunlight compared to pure TiO2. R-t=0.005 sample showed best sunlight photocatalytic performance among the above samples which is 2.3 times (after 30 min) efficient than that of pure nanostructure. (C) 2013 Elsevier B.V. All rights reserved.