Facile synthesis of Ag-Co bimetallic nanoparticles decorated Fe3O4@EDTA nanocomposites and their enhanced catalytic activity

In this study, firstly, bimetallic Ag-Co nanoparticles with rich catalytic sites decorated on Fe3O4 magnetic carriers through metal ion chelating agent EDTA (Ag-Co@EDTA@Fe3O4 NPs) were fabricated by co-reducing agent in-situ deposition method for the first time. The synthesized nanocomposites were characterized by various techniques, including UV–vis, XRD, TEM, EDX, XPS and VSM. Secondly, the catalytic reduction performance of Ag-Co@EDTA@Fe3O4 NPs was analyzed for 2-nitrophenol in the presence of NaBH4 at 25 ℃. Results showed that the k of Ag-Co@EDTA@Fe3O4 NPs was 10.9 and 2.7 times higher than that of Co@EDTA@Fe3O4 and Ag@EDTA@Fe3O4 NPs, respectively, which considered to obey the first-order kinetics equation, proving the strong synergistic effect between Ag and Co nanoparticles. Furthermore, the significantly enhanced catalytic activity of Ag-Co@EDTA@Fe3O4 NPs was discussed. Plenty of Ag NPs were successfully anchored on Fe3O4@EDTA supports maybe the crucial factor, and the doped Co provided much more active sites in the catalytic process. Finally, the degradation efficiency of Ag-Co@EDTA@Fe3O4 NPs still remained above 95% after 5 cycles. Importantly, there was no significant difference between the fresh catalyst and after cycling for 5 times, observed by TEM and SEM. Meanwhile, the change of hydrodynamic diameter of the used Ag-Co@EDTA@Fe3O4 NPs over cycle number was measured around 230 nm which increased unobviously, making it a promising candidate for wastewater treatment in industries.