Synthesis and characterization of photosensitive TiO₂ nanorods by controlled precipitation route

Nanocrystalline TiO₂ thin films have been successfully synthesized by controlled precipitation route. These films are further annealed at 623 K for 2 h. The change in structural, morphological, optical, and wettability properties are studied by means of X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), scanning electron microscopy (SEM), optical absorption, and contact angle measurement. From the XRD pattern it is clear that the as-grown TiO₂ films are amorphous in nature which becomes polycrystalline after annealing. The FTIR study reveals the formation of TiO₂ compound. Scanning electron micrographs shows that the as-grown TiO₂ film consists of agglomerated nanograins well covered to the substrate surface which gets converted into vertical nanorods after annealing. As-deposited and annealed TiO₂ films showed hydrophilic behavior as water contact angles were 24° and 32°, respectively. The optical absorption study reveals the small red shift due to annealing and attributed to grain size. The annealed TiO₂ film showed conversion efficiency of 0.037% in photoelectrochemical cell with 1 M NaOH electrolyte.