(397am) Cooperative Catalytic Activity of á-Cyclodextrin and Ag Nanoparticles in Spherical Polyelectrolyte Brushes

Authors: 
Guo, X., East China University of Science and Technology
Liu, J., East China University of Science and Technology
Wang, J., East China University of Science and Technology
Li, L., East China University of Science and Technology
Lincoln, S., University of Adelaide
Prud'homme, R. K., Princeton University



Spherical poly(acrylic acid) brushes (SPB) were prepared by photo-emulsion polymerization. Positive silver ions were absorbed and concentrated in SPB due to the Donnan effect. Silver nanoparticles (Ag-NP) were synthesized in-situ by reduction of Ag+ upon addition of NaBH4. The nano-composite particles were characterized using TEM, DLS, ICP-AES and UV-vis spectroscopy. While the size distribution of the Ag-NP synthesized at a given temperature is quite uniform this distribution varies with change in synthesis temperature. The lower temperature results in smaller silver nanoparticles. The Ag-NP loaded in SPB have a strong catalytic effect on the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4. The addition of α-cyclodextrin (α-CD) further accelerates this 4-nitrophenol reduction and modifies the associated activation parameters. This is attributed to α-CD complexing 4-nitrophenol in the vicinity of the Ag-NP surface and thereby aiding the catalysis. This work opens a new way to prepare metal nano-particles and to improve their catalysis by addition of CD.