Visible-Light-Responsive TiO₂-Coated ZnO:I Nanorod Array Films with Enhanced Photoelectrochemical and Photocatalytic Performance

Control of structural and compositional characteristics during fabrication of a versatile visible-light active ZnO-based photocatalyst is a crucial step toward improving photocatalytic pollutant degradation processes. In this work, we report a multifunctional photocatalytic electrode, i.e., TiO2 coated ZnO:I nanorods (ZnO:I/TiO2 NRs) array films, fabricated via a hydrothermal method and a subsequent wet-chemical process. This type of hybrid photocatalytic film not only enhances light absorption with the incorporation of iodine but also possesses increased electron transport capability and excellent chemical stability arising from the unique TiO2-coated 1D structure. Owing to these synergic advantages, the degradation efficiency of the ZnO:I samples reached ∼97% after irradiation for 6 h, an efficiency 62% higher than that of pure ZnO. For RhB photocatalytic degradation experiments in both acidic (pH = 3) and alkaline (pH = 11) solutions, as well as in repeat photodegradation experiments, the ZnO:I/TiO2 NRs films demonstrated high stability and durability under visible-light irradiation. Thus, ZnO:I/TiO2 NRs are considered a promising photocatalytic material to degrade organic pollutants in aqueous eco-environments.