Temperature-responsive smart nanoreactors: Poly(N-isopropylacrylamide)- coated Au@mesoporous-SiO2 hollow nanospheres

Zhe Chen, Zhi-Min Cui, Chang-Yan Cao, Wei-Dong He, Lei Jiang, Wei-Guo Song

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73 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)13452-13458
Number of pages7
JournalLangmuir
Volume28
Issue number37
DOIs
Publication statusPublished - 18 Sep 2012
Externally publishedYes

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