Photo-Induced Synthesis of Coral-Like Hierarchical Ag-Fe Bimetallic Multifunctional Nanostructures

Herein, we report, for the first time, rapid and facile photo-induced synthesis of hierarchical Ag-Fe bimetallic nanostructures with tailorable morphologies based on variation of Fe2+ concentrations at the submillimolar level. The synthesis methodology relies on the photo-oscillation of the Fe(II)-Fe(III)-Fe(II) system in the aqueous medium, leading to reduction of Ag+ to Ag-0 nanoparticles,wherein Ag-0 nanoparticles are stabilized in an Fe-oxide framework. The morphology of the product is tailored from scattered to prominent coral-like nanostructures by simply varying the Fe2+ concentrations at the submillimolar level. The developed method eliminates the essential need of presynthesized precursor metal nanoparticles, toxic templates or surfactants, organic solvents, and sophisticated instrumentations or stringent reaction conditions. Coral-like FeFe2O4 nanostructures with hairy extensions ensured high surface area wherein monodispersed nano-Ag-0 (2.31 +/- 1.01 nm) are homogeneously distributed and stabilized without any capping agent. The excellent As3+ removal efficiency (99.9%) of the synthesized material, even from a low but realistic contamination concentration (100 ppb) and high K-d value (4.9 x 10(6) mL/g), is ascribed to the synergistic effect due to reactivity of Ag and Fe toward arsenite. A single treatment with the material (0.15 g/L) efficiently lowers As(III) concentration to well below the U.S. Environmental Protection Agency drinking water limits (10 ppb). Ag-Fe bimetallic also exhibits excellent synergistic antibacterial efficacy against both Gram (+/-) bacteria. Thus, the findings open-up the possibility of expanding the applications of hierarchical Ag-Fe bimetallic nanostructures in water treatment.

Automated summary

This study reports a rapid and facile photo-induced synthesis method for the preparation of tailorable hierarchical Ag-Fe bimetallic nanostructures. The method eliminates the essential need for pre-synthesized precursor metal nanoparticles, toxic templates or surfactants, organic solvents, and sophisticated instrumentation or stringent reaction conditions.