Synthesis of Fe3O4@SiO2@ZnO–Ag core–shell microspheres for the repeated photocatalytic degradation of rhodamine B under UV irradiation

Abstract

Herein, novel Fe3O4@SiO2@ZnO–Ag core–shell microstructures were synthesized through template synthesis and layer-by-layer deposition. The obtained samples were characterized in terms of morphology, composition, optical and magnetic property by various analytical techniques and subsequently tested for the photocatalytic activities. In comparison with Fe3O4@SiO2@ZnO, the as-obtained multi-shelled Fe3O4@SiO2@ZnO–Ag hierarchical microspheres exhibit a significant enhanced photocatalytic activity toward the photodegradation of Rhodamine B (RhB) aqueous solution under UV light. The enhanced photocatalytic activities of the core–shell photocatalyst are primarily ascribed to the reduced recombination probability of photogenerated electrons/holes in the surface of hierarchical microspheres. Moreover, the hierarchical microstructured Fe3O4@SiO2@ZnO–Ag photocatalysts could be easily collected and separated by using a magnetic field and reused without any appreciable decrease on photocatalytic efficiency after running six times. The enhanced photocatalytic performance and magnetic recyclability, in combination with the superior chemical stability, make these multifunctional microstructures promising candidates to eliminate aquatic contaminants and meet the demands of future environmental issues.