Liquid Phase Deposition of α-Fe2O3/ZnO Heterojunction Film with Enhanced Visible-Light Photoelectrocatalytic Activity for Pollutant Removal

Abstract

We developed liquid phase deposition (LPD) technique to prepare α-Fe2O3/ZnO heterojunction film for efficient removal of pollutants by visible-light-driven photoelectrocatalysis (PEC). The deposition of α-Fe2O3 on ZnO film was confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The UV-visible diffuse reflectance spectra (DRS) indicated that the formation of α-Fe2O3 on the surface of ZnO film led to redshift of the absorption edge. Meanwhile, the photoluminescence (PL) spectra revealed that the recombination of photogenerated electrons and holes on α-Fe2O3/ZnO film was remarkably inhibited. As a result, the α-Fe2O3/ZnO film exhibited higher visible-light PEC activity than single α-Fe2O3 or ZnO film. Using the visible-light-activated α-Fe2O3/ZnO film with optimized α-Fe2O3, we studied the effective PEC degradation of diclofenac (DCF) and 4-chlorophenol (4-CP), which represented the emerging and persistent organic pollutants, respectively. Moreover, the α-Fe2O3/ZnO film was successfully applied to simultaneous removal of 4-CP and Cu2+ in wastewater by visible-light PEC process, demonstrating the wide applicability of the LPD α-Fe2O3/ZnO heterojunction film for pollutant removal.