Magnetically recoverable Fe3O4-implanted Ag-loaded ZnO nanoflakes for bacteria-inactivation and photocatalytic degradation of organic pollutants

Abstract

Fe₃O₄-implanted Ag-loaded (0.3 at%) perforated ZnO nanoflakes have been synthesized by a two-step method. Scanning electron and high resolution transmission electron micrographs (HRTEM) display the morphology and the energy dispersive X-ray spectrum confirms the presence of the constituent elements. HRTEM reveals the core/shell structure and Ag-deposition. Selected area electron diffraction pattern displays the presence of Fe₃O₄, ZnO and metallic Ag. The X-ray diffractograms and Raman spectrum are characteristic of the Ag-deposited ZnO lattice. The M–H loop confirms the presence of a magnetic core and the charge transfer resistance of the composite is less than that of pristine ZnO. The nanoflakes display moderate visible light absorption. The UV absorption and emission spectra of the composite are similar to those of pristine ZnO. The decay of photogenerated charge carriers in the nanocomposite is not significantly different from that in pristine ZnO. The composite nanoflakes are magnetically recoverable and inactivate bacteria such as E. coli in the absence of illumination and photocatalytically degrade dyes such as methylene blue effectively. Thus the synthesized composite nanoflakes address (i) bacteria disinfection, (ii) mineralization of organic pollutants and (iii) magnetic recovery of the nanomaterial.