Fast catalytic reduction of an azo dye by recoverable and reusable Fe3O4@PANI@Au magnetic composites

Abstract

In this article, a new method was applied to synthesize magnetically responsive Fe₃O₄@polyaniline (PANI) @Au nanocomposites via a three-step process. Core–shell Fe₃O₄@PANI was prepared by the in situ surface polymerization method with the assistance of sodium dodecyl sulfonate (SDS). By means of electrostatic attraction, as-prepared Au nanoparticles were adsorbed on Fe₃O₄@PANI core–shell composites to fabricate Fe₃O₄@PANI@Au composites, which were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometer (VSM) measurements. The catalytic activity of the Fe₃O₄@PANI@Au composites was evaluated by monitoring the reduction reaction of Congo red. The Fe₃O₄@PANI@Au composite catalyst exhibited excellent catalytic performance at low or high concentration of dye solution. The influences of electrolytes and surfactants on the catalytic reduction rate were studied. Significantly, the Fe₃O₄@PANI@Au composite catalyst showed excellent catalytic performance, good stability and facile recovery by an external magnet.