We use a combination of experiments and first-principles density functional theory based calculations in a study of the photoelectrochemical properties of Fe-doped BaTiO 3 nanopowder. BaTiO 3 with 0.5À4.0 atom % Fe doping is synthesized via a polymeric precursor route and characterized with X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), UVÀvis spectroscopy, and M€ ossbauer spectroscopy. We find a red shift of 0.39 eV in the UVÀvis spectrum and hence an improved photoelectrochemical activity in the visible range upon Fe doping in BaTiO 3 . The origin of the observed activity in the visible range is traced through the calculated electronic structure to the electronic states associated with Fe at energies within the band gap. A reasonable agreement between the changes in measured spectra and those in calculated electronic structure augurs well for a judicious use of first-principles calculations in screening of dopants in the design of doped oxide materials with enhanced photoelectrochemical activity, such as that of Fe-doped BaTiO 3 demonstrated here.

Nanostructured zinc oxide thin films (ZnO) were prepared on conducting glass support (SnO 2 : F overlayer) via sol-gel starting from colloidal solution of zinc acetate 2-hydrate in ethanol and 2-methoxy ethanol. Films were obtained by spin coating at 1500 rpm under room conditions (temperature, 28-35°C) and were subsequently sintered in air at three different temperatures (400, 500 and 600°C). The evolution of oxide coatings under thermal treatment was studied by glancing incidence X-ray diffraction and scanning electron microscopy. Average particle size, resistivity and bandgap energy were also determined. Photoelectrochemical properties of thin films and their suitability for splitting of water were investigated. Study suggests that thin films of ZnO, sintered at 600°C are better for photoconversion than the films sintered at 400 or 500°C. Plausible explanations have been provided.

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