Photocatalytic characteristics of single phase Fe-doped anatase TiO2 nanoparticles sensitized with vitamin B12

We report a processing-structure-property correlation in B-12-anatase titania hybrid catalysts doped with several concentrations of iron. Our results clearly show that low-level iron doping alters structure, defect content, and photocatalytic characteristics of TiO2. XRD and Raman studies revealed formation of a single-phase anatase TiO2 where no iron based segregation in particular iron oxide, was detected. Fr-IR spectra clearly confirmed sensitization of TiO2 nanoparticles with vitamin B-12. TEM micrographs and diffraction patterns confirmed crystallization of anatase nanoparticles with a radius of 15-20 nm. Both XRD and Raman signals showed a peak shift and a peak broadening which are surmised to originate from creation of point defects, namely oxygen vacancy and titanium interstitial. The doped samples revealed a narrower band gap as compared to undoped samples. Photocatalytic activity of the samples was assessed through measuring the decomposition rate of rhodamine B. It was found that sensitization with vitamin B-12 and Fe-doping significantly enhances the photocatalytic efficiency of the anatase nanoparticles. We also showed that there is an optimum Fe-doping level where the maximum photocatalytic activity is achieved. The boost of photocatalytic activity was qualitatively understood to originate from a more effective use of the light photons, formation of point defects, which enhance the charge separation, higher carrier mobility. (C) 2014 Elsevier Ltd. All rights reserved.