Photoelectrocatalytic oxidation of organic compounds at nanoporous TiO2 electrodes in a thin-layer photoelectrochemical cell

A simple, rapid, and effective photoelectrochemical method is proposed to quantitatively characterise photocatalytic degradation behaviour of organic compounds at nanoporous TiO2 film electrodes in a thin-layer photoelectrochemical cell. This method uses the charge obtained by integrating the photocurrent originating from the photocatalytic oxidation of organic compounds to quantify the extent of degradation. Complete mineralisation was observed for all organic compounds investigated. A double-exponential kinetic rate expression was acquired using a computer simulation method, indicating two simultaneous kinetic processes. Photocurrent profiles of different organic compounds complied well with the proposed theoretical model. Both pre-exponential and exponential constants were obtained. The rate of the fast kinetic component is 10–25 times faster than that of the slow kinetic component. It was found that the identities of organic compounds have no significant effect on the photocatalytic oxidation kinetics, whereas the availability of the organic compounds to capture photoholes plays a decisive role.