Facile Hydrogen‐Bond‐Assisted Polymerization and Immobilization Method to Synthesize Hierarchical Fe₃O₄@Poly(4‐vinylpyridine‐co‐divinylbenzene)@Au Nanostructures and Their Catalytic Applications

Abstract

Hierarchical Fe3O4@poly(4-vinylpyridine-co-divinylbenzene)@Au (Fe3O4@P(4-VP-DVB)@Au) nanostructures were fabricated successfully by means of a facile two-step synthesis process. In this study, well-defined core-shell Fe3O4@P(4-VP-DVB) microspheres were first prepared with a simple polymerization method, in which 4-VP was easily polymerized on the surface of Fe3O4 nanoparticles by means of strong hydrogen-bond interactions between -COOH groups on poly(acrylic acid)-modified Fe3O4 nanoparticles and a 4-VP monomer. HAuCl4 was adsorbed on the chains of a P(4-VP) shell and then reduced to Au nanoparticles by NaBH4, which were embedded into the P(4-VP) shell of the composite microspheres to finally form the Fe3O4@P(4-VP-DVB)@Au nanostructures. The obtained Fe3O4@P(4-VP-DVB)@Au catalysts with different Au loadings were applied in the reduction of 4-nitrophenol (4-NP) and exhibited excellent catalytic activity (up to 3025 h(-1) of turnover frequency), facile magnetic separation (up to 31.9 emu g(-1) of specific saturation magnetization), and good durability (over 98 % of conversion of 4-NP after ten runs of recyclable catalysis and almost negligible leaching of Au).

Silk Fiber as the Support and Reductant for the Facile Synthesis of Ag–Fe3O4 Nanocomposites and Its Antibacterial Properties

“…The Fe 3 O 4 –silk fiber composites were prepared through an improved one-step hydrothermal method [22,23]. Typically, FeCl 3 ·6H 2 O (0.1622 g), NaHCO 3 (0.756 g), and vitamin C (0.0294 g) were all dissolved in deionized water (40 mL) under magnetic stirring to form a homogeneous solution.…”

Shape‐Controlled Synthesis of Au–Polypyrrole Composites Using Poly(4‐vinylpyridine) Brush Grafted on Graphene Oxide as a Reaction Chamber

“…[30] In this work, we evaluated the catalytic activity of the GO/P4VP/AuÀPPy nanotubulesc omposites as catalysts by catalyzing the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP)w ith an excessa mount of NaBH 4 .T he solution of 4-NP has an inherent absorption band at l max = 317 nm. [32] The bright-yellow reactions olution gradually becamec olorless within 16 minutes (as shown in Figure 5B). [31] Time-dependenta dsorption spectra of this reactions howt he disappearance of the peak at 400 nm, which was accompanied by ag radual development of an ew peak at about3 00 nm, corresponding to the formation of 4-AP.…”

Design and Synthesis of an Au@MIL‐53(NH2) Catalyst for a One‐Pot Aerobic Oxidation/Knoevenagel Condensation Reaction

“…[1][2][3] Particularly noble metal nanoparticles have high catalytic activity and selectivity owing to abundant active surface atoms. [4,5] Au NPs exhibit remarkable catalytic activity in several reactions including oxidations, [6][7][8][9] C-C coupling reactions, [10] alkylations [11] and cyclization reactions. [12] However the catalytic efficiency of Au NPs in the reactions was restricted due to their aggregation.…”

“…[13] Therefore, the immobilization of Au NPs on porous supports is regarded as one of the most practical ways to address this problem. Inorganic materials such as SiO 2 , [14,15] TiO 2 , [16,17] and porous carbon [18,19] and organic materials such as poly(4-vinylpyridine), [5] poly(ethylene glycol) dimethacrylate [20] and polyaniline [21] have been utilized as supports to deposit Au NPs. Recently, metal-organic frameworks (MOFs) have been studied as important functional materials due to their tunable crystalline structures and features such as porosity, high surface area and structural flexibility.…”