A highly reactive and magnetic recyclable catalytic system based on AuPt nanoalloys supported on ellipsoidal Fe@SiO2

Abstract

A facile method has been developed for the synthesis of highly active and well-defined AuPt nanoalloys supported on the surface of ellipsoidal Fe@SiO₂ nanoparticles. This method involves the loading of Pt NPs on the Fe₂O₃@SiO₂ nanocapsules via Sn²⁺ linkage and reduction, then in situ fabrication of Au nanoparticles by the galvanic replacement reaction between Au and Pt, and finally calcination and reduction to convert the nonmagnetic Fe₂O₃ to Fe core with high saturation magnetization. XRD and XPS analysis demonstrates the alloy structure of AuPt nanoparticles in the final samples. The obtained Fe@SiO₂/AuPt samples exhibit a remarkably higher catalytic activity in comparison with the supported monometallic counterparts toward the reduction of 4-nitrophenol to 4-aminophenol by NaBH₄. The catalyst can be reused for several cycles with convenient magnetic separation.