Photoelectrocatalytic degradation of benzoic acid using sprayed TiO2 thin films

Transparent TiO2 thin films have been sucessfully synthesized by chemical spray pyrolysis technique. The effect of substrate temperature on the photoelectrochemical (PEC), structural, morphological, optical and photoelectrocatalytic properties has been investigated. The PEC study shows that both short circuit current (Isc) and open circuit voltage (Voc) at the optimized substrate temperature (450 °C) are relatively maximum (Isc=1.7 mA and Voc=770 mV). The tetragonal crystal structure has been confirmed from X-ray diffraction patterns. FE-SEM study reveals that the film surface is changed from nanogranular to nanorod like morphology. The films exhibit a transmittance of about 80% in the visible region and a sharp absorption edge at 375 nm corresponding to the fundamental absorption edge in UV region. Band gap energy varies from 3.33 to 3.43 eV with substrate temperature. Electron-phonon coupling present in TiO2 films has been analyzed using Raman spectroscopy. The elemental composition and valence states of TiO2 film are studied by using X-ray photoelectron spectroscopy. The effect on the photoelectrocatalytic behavior of the large surface area (64 cm2) TiO2 photocatalyst samples were studied by using photoelectrocatalytic degradation of benzoic acid under UV light illumination.