Host–Guest Interaction Induced Rapid Self-Assembled Fe₃O₄@Au Nanoparticles with High Catalytic Activity

A novel Fe₃O₄@Au nanocatalyst was successfully self-assembled induced by host–guest interaction between ferrocene and β-cyclodextrin. This self-assembly system consisted of Fe₃O₄ nanoparticles modified with ferrocene (Fe₃O₄@Fc) and gold nanoparticles coated with β-cyclodextrin (Au@CD). The self-assembly process between these two kinds of nanoparticles was extremely fast, and the self-assembled Fe₃O₄@Au nanoparticles showed high catalytic activity for the reduction of 4-nitrophenol. Fe₃O₄@Au nanoparticles demonstrated good magnetic recoverability and high conversion (>98%) after 10 successive cycles. The stable uniform distribution of gold nanoparticles on the surface of Fe₃O₄ played an important role in the enhancing catalytic activity. Meanwhile, β-cyclodextrin promoted the catalytic performance since it could tether the 4-nitrophenol to the gold nanoparticles. Furthermore, this self-assembly system exhibited good store stability even for 6 months and could be controllably redox-responsive disassembled. This facile self-assembly method could serve as inspiration in catalysis, biosensor, bioseparation, SERS detection, and so on.