The influence of ZnO loading amount on the photocatalytic performance of Fe3O4@SiO2@ZnO–Ag composites toward the degradation of organic pollutants and hydrogen evolution

Abstract

Rational design of hierarchical photocatalysts for dye degradation and hydrogen production has been believed as a wise selection for pollution control and energy solution. Herein, we present the design and synthesis of Fe₃O₄@SiO₂@ZnO–Ag core shell microstructures with different ZnO loading amounts. The structure, morphology, composition, optical and magnetic properties of the as-synthesized samples were investigated by several characterization techniques. Photocatalytic degradation of rhodamine B (RhB) and hydrogen evolution under UV light were selected to assess the impact of ZnO loading amount on photocatalytic activities. Photocatalytic results reveal that Fe₃O₄@SiO₂@ZnO–Ag with 15.14 wt% ZnO loading amount shows the best photocatalytic property. The RhB degradation efficiency of this sample was 98.1% after 100 min of UV light exposure. Additionally, the hydrogen evolution rate of this sample was 183 μmol h⁻¹ under UV light illumination. It is also worth noting that these core shell microspheres were endowed with outstanding magnetic response, excellent photocatalytic reusability and chemical stability. The core shell photocatalysts can maintain high efficiency after five-cycles of RhB photocatalytic degradation run. Such features mentioned above made heterostructure Fe₃O₄@SiO₂@ZnO–Ag photocatalysts promising candidates in practical use for environmental and energy challenges.