title: Synthesis of Self-Assembled Multifunctional Nanocomposite Catalysts with Highly Stabilized Reactivity and Magnetic Recyclability.
abstract: In this paper, a multifunctional Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite catalyst with highly stabilized reactivity and magnetic recyclability was synthesized by a self-assembled method. The magnetic Fe3O4 nanoparticles were coated with a thin layer of the SiO2 to obtain a negatively charged surface. Then positively charged poly(ethyleneimine) polymer (PEI) was self-assembled onto the Fe3O4@SiO2 by electrostatic interaction. Next, negatively charged glutathione capped gold nanoparticles (GSH-AuNPs) were electrostatically self-assembled onto the Fe3O4@SiO2@PEI. After that, silver was grown on the surface of the nanocomposite due to the reduction of the dopamine in the alkaline solution. An about 5 nm thick layer of polydopamine (PDA) was observed to form the Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was carefully characterized by the SEM, TEM, FT-IR, XRD and so on. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite shows a high saturation magnetization (Ms) of 48.9 emu/g, which allows it to be attracted rapidly to a magnet. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was used to catalyze the reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) as a model system. The reaction kinetic constant k was measured to be about 0.56 min(-1) (R(2) = 0.974). Furthermore, the as-prepared catalyst can be easily recovered and reused for 8 times, which didn't show much decrease of the catalytic capability.
authors.affiliation: Micro &Nano Integrated Biosystem (MINIBio) Laboratory, Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Xu
authors.initials: X
authors.lastname: Yu
authors.affiliation: Micro &Nano Integrated Biosystem (MINIBio) Laboratory, Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Gong
authors.initials: G
authors.lastname: Cheng
authors.affiliation: Micro &Nano Integrated Biosystem (MINIBio) Laboratory, Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Si-Yang
authors.initials: SY
authors.lastname: Zheng
mesh_terms: D000627:Aminophenols / Q000737:chemistry*; D002384:Catalysis; D017743:Equipment Reuse; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D007211:Indoles / Q000737:chemistry; D007700:Kinetics; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D009596:Nitrophenols / Q000737:chemistry*; D010084:Oxidation-Reduction; D011094:Polyethyleneimine / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry; D055672:Static Electricity
chemical_list: D000627:Aminophenols; D007211:Indoles; D058185:Magnetite Nanoparticles; D009596:Nitrophenols; D011108:Polymers; C568283:polydopamine; D012834:Silver; D006046:Gold; D012822:Silicon Dioxide; D011094:Polyethyleneimine; C026729:4-aminophenol; D052203:Ferrosoferric Oxide; C024836:4-nitrophenol