Enhanced photocurrent generation and photooxidation of benzene sulfonate in a continuous flow reactor using hybrid TiO2 thin films immobilized on OTE electrodes

Abstract

Abstract The enhancement of photocurrent and photodegradation of organic pollutants was investigated using hybrid TiO 2 thin films prepared by a combined paste/sol–gel technique to immobilize the TiO 2 particles onto optically transparent electrodes (OTEs); they were connected in series in a continuous flow, bench-top, two-compartment photoreactor. The benzene sulfonate (BS) of the model substrate surfactant used was photodegraded in aqueous media to test the efficacy of the TiO 2 /OTE electrode preparation and the construction of the photoreactor. Results indicate that the hybrid TiO 2 film/OTE electrodes were more efficient than either the pasted TiO 2 /OTE electrode or the sol–gel TiO 2 /OTE electrode for the photodegradation of BS, as evidenced by the evolution of carbon dioxide and the photocurrent generated. The extent of ring opening and generated photocurrent during the photodegradation of BS with the hybrid (HY) electrode was correlated to the pasted TiO 2 electrode and to the number of dip-coatings in the sol–gel. High photocurrents were generated in the cylindrical large photoreactor under continuous flow of the aqueous BS solution. Optimization of experimental factors for optimal efficiency of the setup was addressed with regard to the preparation of the HY electrodes, and to their size and location in the photoreactor.