Preparation, characterization and photoelectrocatalytic properties of nanocrystalline Fe2O3/TiO2, ZnO/TiO2, and Fe2O3/ZnO/TiO2 composite film electrodes towards pentachlorophenol degradation

Abstract

Nanocrystalline TiO₂ composite thin ZnO/TiO₂, Fe₂O₃/ZnO/TiO₂ and Fe₂O₃/TiO₂ films were developed on titanium substrates by applying dip-coating technique formed by the sol–gel method. Scanning electron microscopy (SEM) evaluated the surface characteristics of the films. Results on their structure and crystallinity were obtained by means of X-ray diffraction. The samples were also characterized by X-ray energy dispersive spectrometer (EDS) and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic activity of these films towards photodegradation of pentachlorophenol pollutant was examined and their efficiency was compared to those of the different TiO₂films. It has been shown that the film photocatalysts can efficiently decompose the pollutant. The photoelectrocatalytic degradation of PCP showed important variation that decreases in the order: ZnO/TiO₂ > TiO₂ > Fe₂O₃/ZnO/TiO₂ > Fe₂O₃/TiO₂. The results showed that Zn²⁺ doped could improve PEC activity of titania film electrode while Fe³⁺ doped can not improve that of titania film electrode.