Structural modification and property tailoring in titania for high efficiency in sunlight

The effect of doping lanthanide ions into nano titania by pulverization technique is investigated for efficient photon absorption in sunlight. The structural modification and its effect on properties of titania were characterized and analyzed by XRD, EDX, SEM, TEM, BET and spectral studies. X-ray and electron diffraction patterns indicate a nanostructure with retention of anatase phase. XRD and EDX analyses detected the presence of neodymium in titania. Doping caused substantial growth of around 25% in particle size. An enhanced activity of optimally doped Nd titania in sunlight is attributed to the lower band gap energy corresponding to a red shift of 57 nm and the arise of mid bands (4f and 5d) as electron traps and defect centers (Ti3+) as hole traps, favoring efficient shallow trapping and detrapping nature of the charge carriers. The effect of the broader absorption range on photocatalytic activity has been investigated by comparative studies in three different sources of light namely sunlight, UV light and in tungsten source of light.

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► Doping lanthanide ions were carried by pulverization process.
► The incorporation of ions through crystallization of a preferred phase was proved.
► Red shift of band edge due to ‘f’ transitions helps in efficient photon absorption.
► Shallow trapping and detrapping enhances interfacial charge transfer.
► The effect of traps and narrow band gap masks the adverse effect of surface area.