Temperature-Responsive Smart Nanoreactors: Poly(N-isopropylacrylamide)-Coated Au@Mesoporous-SiO2 Hollow Nanospheres
| Autor: | Wei-Dong He, Zhe Chen, Changyan Cao, Weiguo Song, Lei Jiang, Zhimin Cui |
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| Rok vydání: | 2012 |
| Předmět: |
Models
Molecular Thermogravimetric analysis Materials science Polymers Surface Properties Acrylic Resins Metal Nanoparticles Nanoparticle Nanoreactor Lower critical solution temperature chemistry.chemical_compound Polymer chemistry Electrochemistry General Materials Science Particle Size Fourier transform infrared spectroscopy Spectroscopy Acrylamides Temperature Surfaces and Interfaces Mesoporous silica Silicon Dioxide Condensed Matter Physics Chemical engineering chemistry Poly(N-isopropylacrylamide) Gold Mesoporous material Porosity Nanospheres |
| Zdroj: | Langmuir. 28:13452-13458 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | A nanoreactor with temperature-responsive poly(N-isopopylacrylamide) (PNIPAM) coated on the external pore mouth of mesoporous silica hollow spheres and Au nanoparticles at the internal pore mouth were fabricated. Such spatial separation allows both Au nanoparticles and PNIPAM to function without interfering with each other. Transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectra, and temperature-dependent optical transmittance curves demonstrate successful grafting of PNIPAM. This nanoreactor shows repeated on/off catalytic activity switched by temperature control. It shows excellent catalytic activity toward 4-nitrophenol (4-NP) reduction at 30 °C [below lower critical solution temperature (LCST) of PNIPAM] with a turnover frequency (TOF) of 14.8 h(-1). However, when the temperature was 50 °C (above LCST), the TOF dropped to 2.4 h(-1). Kinetic studies indicated that diffusion into the mesopores of the catalyst was the key factor, and the temperature-responsive behavior of PNIPAM was able to control this diffusion. |
| Databáze: | OpenAIRE |
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