Abstract: Nanosize TiO2 film,immobilized on an ITO (Indium Tin Oxide) glass, was successfully fabricated. The film was prepared by a dip coatingtechnique in a hydrothermal sol-gel system and subjected to a heat treatment at 100°C up to 450°C. Characterization ofthe film by XRD, AFM, BET methods revealed the occurrence of anatase form and 9.64 nm in crystallite size; having three dimensional profile and roughness with height of typically 9.8 nm; and surface area of 58.21 m2/g. The film thenwas employed as a working electrode in a photo electrochemical system (PES). This PES generated a photocurrent that proportional to the organic chemical concentration in the water sample. Integration of the photocurrent versus timegives a charge (Q) that represent the event of complete mineralization of organic chemical in the TiO2 surface and canbe correlated to the Chemical Oxygen Demand (COD) of measured water. This system has a potential to be developed for a novel COD sensor
Abstract: Photocatalytic reduction of CO2 by copper-doped titania catalysts has been investigated. The photocatalysts with various copper species (Cu0, CuI, CuII) were prepared by an improved-impregnation method, where copper nitrate is doped into TiO2 Degussa-P25. It is likely that copper present on the catalyst surface and the grain size of copperâtitania catalysts is uniform, with crystallite size approximately 23 nm. The dispersion capacity of CuO in the vacant sites of TiO2 is about 4.16 Cu2+ nmâ2 (â2.2 wt% of Cu), as indicated by XRD analysis. The activation energy (Ea) for Degussa-P25 and 3%CuO/TiO2 is ca. +26 and +12 kJ/mol, respectively. These Ea values suggest that the desorption event is a rate limiting step, and the lower Ea of 3%CuO/TiO2 may suggest a catalytic role of copper species that enhance the methanol production.
