Thermosensitive Au-PNIPA Yolk-Shell Nanoparticles with Tunable Selectivity for Catalysis
ABSTRACT Selectivity in nanoreactors: A hybrid yolk-shell nanostructure that contains gold nanoparticles in the core and thermosensitive microgel poly(N-isopropylacrylamide) (PNIPA) as shell is presented. The catalytic selectivity of Au-PNIPA nanoparticles for the reduction of hydrophilic 4-nitrophenol and more hydrophobic nitrobenzene with NaBH(4) can be tuned through the volume transition of PNIPA shell.
Macromolecular Research 03/2015; 23(3). DOI:10.1007/s13233-015-3038-9 · 1.68 Impact Factor
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ABSTRACT: A smart hollow hybrid system was prepared by introducing poly(2-(1-methylimidazolium 3-yl)-ethyl methacrylate chloride) (PMIMC) network, the temperature-responsive PDMAEMA brushes, and Au nanoparticles into silica nanoparticles through two-step surface-initiated atom transfer radical polymerization. TEM, FTIR, EDX, XRD, XPS, and TGA were used to characterize the morphology and structure of air@PMIMC-PDMAEMA-Au hairy hollow nanospheres. The result showed that Au nanoparticles with an average diameter of 1.5 ± 0.2 nm were homogeneously embedded inside the PMIMC-PDMAEMA shell. Catalytic activity of the as-synthesized air@PMIMC-PDMAEMA-Au hairy hollow nanospheres were investigated using the reduction of 4-nitrophenol with NaBH4 as a model reaction. It was found that the joint structures of PMIMC hollow nanospheres and PDMAEMA brushes lead to production of the highly active and stable catalyst for reduction of 4-nitrophenol. Furthermore, the obtained air@PMIMC-PDMAEMA-Au hairy hollow nanospheres were found to have a thermally adjustable catalytic activity for the reduction of 4-nitrophenol.Journal of Nanoparticle Research 02/2015; 17(2). DOI:10.1007/s11051-015-2872-1 · 2.28 Impact Factor
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ABSTRACT: Developing hydrogel systems featured by catalytic active is of importance to construct highly effective platforms for removing environmental pollutants/hazardous substances or for bio-/chemosensing. Reported herein are our recent finding that Au nanoparticles could be in situ prepared in chitosan-AuIII hydrogel system via photoreduction, and the as-prepared Au nanoparticles could be employed for the catalytic reduction of a series of nitroaromatic compounds by sodium borohydride (NaBH4). Experimental conditions of synthesizing Au nanoparticles, including pH, concentration of AuIII, and light irradiation time were systematically investigated. The as-prepared Au nanoparticles were characterized by UV–vis absorption spectroscopy, X-ray diffraction (XRD), transmission and field emission scanning electron microscopy (TEM and FESEM). This is the first example for in situ formed metal nanoparticles in chitosan hydrogel systems via photoreduction. The effectiveness of the as-prepared Au nanoparticles as nanocatalysts was evaluated by employing the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 as a model reaction. The catalytic reduction reaction was found to be very efficient and to follow a pseudo-first-order kinetics. The as-prepared Au nanoparticles demonstrated good reusability and stability. The reduction of a series of other nitroaromatic compounds including highly explosives 2,4,6-trinitrophenol (2,4,6-tNP) and 2,4,6-trinitrotoluene (2,4,6-tNT) was achieved by means of this catalytic system.Applied Surface Science 03/2015; 331. DOI:10.1016/j.apsusc.2015.01.077 · 2.54 Impact Factor