Synthesis, Characterization, and Photocatalytic Activity of Magnetically Separable Fe3O4@SiO2@ZnO–Ag Composite Photocatalyst

Magnetically separable Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂@ZnO, and Fe₃O₄@SiO₂@ZnO–Ag composites are synthesized using hydrothermal and wet chemistry methods. The samples obtained are characterized in terms of morphology, composition, optical, and magnetic properties using TEM, SEM-EDS, XRD, FTIR, VSM, XPS, and UV–vis, and the photodegradation of Acid Blue 161 dye under UV irradiation is investigated. As a result of SEM and TEM analyses, the diameters of Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂@ZnO, and Fe₃O₄@SiO₂@ZnO–Ag composites are determined as 210, 220, 230 and 235 nm, respectively. The magnetic properties of the samples are determined by VSM analysis. In VSM analyses, magnetization saturation values of Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂@ZnO, and Fe₃O₄@SiO₂@ZnO–Ag composites are determined as 81, 64, 41 and 20 emus × ^g−1, respectively. In XRD analysis, the face-centered cubic structure of Fe₃O₄ particles and the hexagonal wurtzite structure of ZnO are determined and it is determined that they are compatible with standard diffraction cards. According to UV–Vis analysis, E_g values for Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂@ZnO, and Fe₃O₄@SiO₂@ZnO–Ag composites are found as 1.3, 1.68, 2.21, and 2.15 eV, respectively. Among the photocatalysts prepared, Fe₃O₄@SiO₂@ZnO–Ag composite Acid Blue 161 shows superior removal and recyclability against photodegradation of the dyestuff.