Photoelectrochemical properties of sol-gel derived TiO2 thin films in aqueous sodium oxalate solution

Photoelectrooxidation of aqueous sodium oxalate on TiO2 thin films has been investigated. The films, prepared by sol-gel dip-coating, were characterised using Scanning Electron Microscopy and X-ray Diffractometry. Photosensitivity of samples was studied using Linear Sweep Voltammetry and Chronoamperometry techniques. The photoelectrochemical performance of thin film electrodes was evaluated in function of heat treatment, number of dip-coatings and applied potential. The percentage of oxalate degradation was determined by calculating the total charge from the photocurrent. The films heat-treated at 773 K were better fitted to indirect optical transition with Eg = 3.21 eV.