Zinc titanate nanomaterials—photocatalytic studies and sensitization of hydantoin derivatized porphyrin dye

Abstract

ZnTiO3 cubic nanomaterials were synthesized hydrothermally under surfactant free conditions, in presence of the inexpensive material urea. Calcination at 6000C yields highly crystalline hexagonal stoichiometric ZnTiO3 phase (as confirmed from powder X-ray diffraction, X-ray photoelectron spectra and Raman studies). This is in contrast to earlier reports, which said that ZnTiO3 can be synthesized at much higher temperature i.e. 9450C. Distinct signatures of Zn-O and Ti-O vibrations were manifested in the IR spectra with concomitant decrease in intensity of -NH and -CO stretching frequencies of urea. Thus urea plays a critical role in formation and stabilization of the ZnTiO3phase. The ZnTiO3 nanomaterials showed much superior photo catalytic efficiency than TiO2 nanomaterials due to enhanced electron–hole separation in the former because electrons can easily get transferred from the conduction band (CB) of Ti to CB of Zn. Surface studies indicate larger pore volume and pore diameter of the ZnTiO3 nanomaterials. The ZnTiO3 nanomaterials also get effectively sensitized by a porphyrin dye (PHy) synthesized with hydantoin anchoring groups. Electron injection rate from PHy to ZnTiO3 is much higher than from PHy to TiO2 implying the prospect of using the titanate nanomaterials as photoanode materials in dye sensitized solar cells (DSCs).