This document describes research on raspberry-like polymer composite spheres coated with different amounts of gold nanoparticles (AuNPs) for use as recyclable catalysts. The spheres were tested for their catalytic properties in reducing 4-nitrophenol to 4-aminophenol with sodium borohydride. The catalytic activity was stable through multiple recycling cycles and was influenced by the amount of AuNPs coated and the solution pH. Scanning electron microscopy images show the raspberry-like structure of the composite spheres coated with AuNPs.

1. RECOVERING CATALYTIC PROPERTIES OF RASPBERRY-LIKE
POLYMER COMPOSITE SPHERES DEPOSITED WITH DIFFERENT GOLD
NANOPARTICLES AMOUNT
Maolin Li, Yuanchang Liu and Guofang Chen*
Chemistry Department, St. John’s University, Queens, NY 11439 Tel.: 718-990-8092; E-mail: cheng@stjohns.edu
Objective
Spectra of absorbance trend vs time
Acknowledgements
Gold nanoparticles (AuNPs) are highly active and can efficiently catalyze many reactions. However, easy aggregation and hard recovery of the AuNPs catalyst
from the products reduce their original catalytic activities and limit their wide applications. The immobilization of the gold nanoparticles on supports is a
practical way for such catalysts to retain high activity on recycling. Here a new raspberry-like polymer composite sphere deposited with different gold
nanoparticles amount was prepared. The catalytic properties and stability of such composite spheres coated with different AuNPs amount were studied by the
reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AnP) with sodium borohydride (NaBH4) as reductant, The catalytic properties of the stabilized catalyst
for recycling were also investigated.
SEM Top View Enlarged View
Successive UV-vis absorption spectra of the
reduction of 4-nitrophenol by NaBH4 in the
presence of PGMA-AuNP microsphere
The logarithm of concentration/initial
concentration at 400 nm vs. reduction time
(d)
Kinetics of PGMA-AuNP microsphere at
different pH
Kinetics of PGMA-AuNP microsphere in
different PAH amount
Kinetics of different ratio of PGMA-
AuNP microsphere in 0.1% PAH
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100 nm
Synthesis of raspberry-like composite
spheres
•We acknowledge St. John's University for
the start-up funding and Seed Grant
support.
•Research carried out in part at the Center
for Functional Nanomaterials, Brookhaven
National Laboratory, which is supported
by the U.S. Department of Energy, Office of
Basic Energy Sciences, under Contract
No. DE-AC02-98CH10886
0 10 20 30 40 50 60
0.00000
0.00002
0.00004
0.00006
0.00008
0.00010
0.00012
0.00014 0.1PAH-0.2mL
0.1PAH-0.4mL
0.1PAH-0.6mL
0.5PAH-0.2mL
0.5PAH-0.4mL
0.5PAH-0.6mL
0.75PAH-0.2mL
0.75PAH-0.4mL
0.75PAH-0.6mL
1.0PAH-0.2mL
1.0PAH-0.4mL
1.0PAH-0.6mL
CA
(mol/L)
Time (min)
0 10 20 30 40 50
0.00000
0.00002
0.00004
0.00006
0.00008
0.00010
0.00012
0.00014
pH3-0.2mL
pH3-0.4mL
pH3-0.6mL
pH5-0.2mL
pH5-0.4mL
pH5-0.6mL
pH7-0.2mL
pH7-0.4mL
pH7-0.6mL
pH9-0.2mL
pH9-0.4mL
pH9-0.6mL
pH11-0.2mL
pH11-0.4mL
pH11-0.6mL
CA
(mol/L)
Time (min)
0 2 4 6 8 10 12 14 16 18 20
0.00000
0.00004
0.00008
0.00012
0.00016
0.00020
0.00024
0.00028
100/1-0.2mL
100/1-0.4mL
100/1-0.6mL
100/2-0.2mL
100/2-0.4mL
100/2-0.6mL
100/4-0.2mL
100/4-0.4mL
100/4-0.6mL
100/10-0.2mL
100/10-0.4mL
100/10-0.6mL
CA
(mol/L)
Time (min)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 2 4 6 8 10 12 14
Time (min)
Absorbance
Absorbance (AU) 300 nm
Absorbance (AU) 400 nm
y = -0.157x + 0.0689
R
2
= 0.9923
-2.5
-2
-1.5
-1
-0.5
0
0 2 4 6 8 10 12 14
Time(min)
Ln(Ca/Co)
Ln(Ca/Co)
Linear (Ln(Ca/Co))
Absorbance trend vs. time at 300 and 400
nm
Catalytic activity of the PGMA-AuNP nanocolloids was
investigated through the reduction of 4-nitrophenol (4-NP) to
4-aminophenol (4-AnP) under an ambient temperature of
about 25℃.