Synthesis and characterization of magnetically separable Ag nanoparticles decorated mesoporous Fe3O4@carbon with antibacterial and catalytic properties

Mesoporous composite particles of carbon inlaid with Fe3O4 nanoparticles (designated as Fe3O4@carbon) with a novel bowl structure and magnetic separation property were fabricated by a spray drying assisted template method using chitosan as carbon precursor and silica nanoparticles as pore directing agent. The influence of the contents among Fe3O4 nanoparticles, chitosan and silica nanoparticle on the formation of porous Fe3O4@carbon composite particles has been discussed. Ag nanoparticles were then deposited onto the surface of mesoporous Fe3O4@carbon substrates using silver acetate as precursor with the assistance of ultrasound treatment. The matrices of Ag nanoparticles decorated Fe3O4@carbon composite particles (denoted as Ag–(Fe3O4@carbon)) were derived and characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR) spectroscopy, nitrogen adsorption–desorption, and magnetic property measurements. The Ag–(Fe3O4@carbon) composites showed efficient antibacterial activities to Escherichia coli and Staphylococcus aureus, high catalytic activity to the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4, strong adsorption ability to organic molecules, and efficient separability under a magnetic field.