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 (L–H) kinetic model with pseudo-first-order apparent rates of 3.2×10−2, 5.3×10−2, 8.9×10−2 and 7.1×10−2 for Co doped nanofibers of Rt=0.0, 0.0025, 0.005, 0.01 (where Rt is the molar ratio of Co(OAc)2 to Ti(OiPr)4). The result showed that Co2+ doped nanostructure significantly enhanced the photocatalytic degradation of methyl orange under direct sunlight compared to pure TiO2. Rt=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.