Facile synthesis of ZnO/CuInS₂ nanorod arrays for photocatalytic pollutants degradation

Highlights: • Vertically-aligned ZnO nanorod arrays were synthesized by the hydrothermal process. • Monodisperse CuInS₂ QDs were synthesized by the one-pot colloidal chemistry method. • ZnO/CuInS₂ nanorod arrays films were fabricated by the EPD process. • The homogeneous CuInS₂ loading was optimized by EPD duration. • The photoelectrochemical and photocatalytic activities of the ZnO/CuInS₂ nanorod arrays films were discussed. - Abstract: Vertically-aligned ZnO nanorod arrays on a fluorine-doped tin oxide glass substrate were homogeneously coated with visible light active CuInS₂ quantum dots by using a controllable electrophoretic deposition strategy. Compared with the pure ZnO nanorod arrays, the formation of high-quality ZnO/CuInS₂ heterojunction with well-matched band energy alignment expanded the light absorption from ultraviolet to visible region and facilitated efficient charge separation and transportation, thus yielding remarkable enhanced photoelectrochemical performance and photocatalytic activities for methyl orange and 4-chlorophenol degradation. The ZnO/CuInS₂ film with the deposition duration of 80 min showed the highest degradation rate and photocurrent density (0.95 mA/cm²), which was almost 6.33 times higher than that of the pure ZnO nanorod arrays film. The CuInS₂ QDs sensitized ZnO nanorod arrays film was proved to be a superior structure for photoelectrochemical and photocatalytic applications due to the optimized CuInS₂ loading and well-maintained one-dimensional nanostructure.