Z-scheme recyclable photocatalysts based on flower-like nickel zinc ferrite nanoparticles/ZnO nanorods: Enhanced activity under UV and visible irradiation

Hybrid photocatalysts with magnetism are important because of their advantage of being recyclable by a magnet. In this paper, we report the synthesis of magnetic flower-like nanocomposites based on ZnO nanorods and nickel zinc ferrite (NZF) nanoparticles using a hydrothermal method. The magnetic cores of NZF nanoparticles with diameter of 30–50 nm were used as the centers for the subsequent ZnO nanorods growth. ZnO nanorods grow from these magnetic cores to form scattered flower-like nanostructures, while their length is controlled by changing the heating time. These flower-like nanostructures have distinctive morphology with large surface-to-volume (S/V) ratio. When used as a photocatalyst, these hierarchical nanocomposites show high photocatalytic activity in the degradation of organic contaminates under ultraviolet (UV) and visible light irradiation. Their excellent photocatalysis attributes to the wide absorption range of NZF and the simple Z-scheme system between ZnO and NZF that enhances the charge separation efficiency. In addition, these nanocomposites present sufficient magnetization such that they can be rapidly separated from the solution by a magnet. These recyclable photocatalysts with high efficiency under UV and visible light are ideal for purifying organic contaminants.