Catalytic and antibacterial activity of Ag decorated magnetic core shell nanosphere.

We report a facile approach for the preparation of Ag nanoparticles decorated magnetic Fe3O4@SiO2 core shell nanosphere (Ag-MCN) and investigated its potential application for the catalytic reduction of organic pollutants and inhibition of bacterial pathogens. The successful formation of Ag-MCN was confirmed by X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The average size of this nanosphere was found to be 85nm and it exhibits superparamagnetic behavior at room temperature. These nanospheres even at low concentration and short incubation period showed good catalytic performance for the reduction of Rhodamine B (RhB) and 4-nitrophenol (4-NP). Further, these magnetic nanosphere possess good antibacterial activity for Gram negative, Escherichia coli (E. coli). Ag-MCN are found to be efficient for complete inhibition of E. coli at a concentration of 50mgL(-1) after incubation for a period of 3h. Furthermore, the generation of reactive oxygen species (ROS) by nanosphere and its effect in the antibacterial activity has been investigated. These nanospheres exhibit good colloidal stability, recycling capability, and could be easily separated from solution via external magnet.