Fe3O4/Polypyrrole/Au Nanocomposites with Core/Shell/Shell Structure: Synthesis, Characterization, and Their Electrochemical Properties

Abstract

Uniform Fe₃O₄ nanospheres with a diameter of 100 nm were rapidly prepared using a microwave solvothermal method. Then Fe₃O₄/polypyrrole (PPy) composite nanospheres with well-defined core/shell structures were obtained through chemical oxidative polymerization of pyrrole in the presence of Fe₃O₄; the average thickness of the coating shell was about 25 nm. Furthermore, by means of electrostatic interactions, plentiful gold nanoparticles with a diameter of 15 nm were assembled on the surface of Fe₃O₄/PPy to get Fe₃O₄/PPy/Au core/shell/shell structure. The morphology, structure, and composition of the products were characterized by transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The resultant nanocomposites not only have the magnetism of Fe₃O₄ nanoparticles that make the nanocomposites easily controlled by an external magnetic field but also have the good conductivity and excellent electrochemical and catalytic properties of PPy and Au nanoparticles. Furthermore, the nanocomposites showed excellent electrocatalytic activities to biospecies such as ascorbic acid (AA).