!

!

!

"

#"

$"

%"

&"

'""

"(""'"""'(""#"""#("")""")(""$"""

!"#$%&

'((#$)*+,-!.

/#0*1*$2(3+,)&45.

6*78"*+9#1)'$#('8$

"

#"

$"

%"

&"

'""

'#"

"(""'"""'(""#"""#("")""")(""$"""

!"#$%&

'((#$)*+,-!.

/#0*1*$2(3+,)&45.

:7(*"+9#1)'$#('8$

!

!

!

"

#"

$"

%"

&"

'""

"(""'"""'(""#"""#("")""")(""$"""

!"#$%&

'((#$)*+,-!.

/#0*1*$2(3+,)&45.

6*78"*+9#1)'$#('8$

"

#"

$"

%"

&"

'""

'#"

"(""'"""'(""#"""#("")""")(""$"""

!"#$%&

'((#$)*+,-!.

/#0*1*$2(3+,)&45.

:7(*"+9#1)'$#('8$

Synthesis of Catalytic Gold Nanoparticles for Oxidation of Benzyl Alcohol

Shirley Peng1, Mei Shan Ng2, Edgar Catari3, Mario Meneghetti31SUNY Oswego, 2SUNY Binghamton, 3Federal University of Alagoas

Conclusion References

Acknowledgements

Introduction Experimental Procedures

Objectives

Results

• Nanoscale gold particles have attractive size and optical properties ideal for catalytic activities

• Properties and behaviors of nanoparticles are size-dependent

• High surface area in relation to its volume makes nanoscale materials more reactive than larger-scale materials

• Gold nanoparticles are an extremely efficient, green catalyst since they offer the possibility of catalytic oxidation that uses atmospheric air as the oxidant and forms water as the only byproduct

• Synthesis and characterization of gold hollow mesoporous silica spheres with worm channels

• Application of the prepared nanoparticles as a catalyst in the oxidation of benzyl alcohol

• Preparation of AuNPs• 9.16mL of HAuCl4 dissolved in deionized water to make

a 150mL solution • Addition of 3% w/w sodium citrate (0.15g) in

deionized water to reduce Au3+ to Au0 (reflux for 30 minutes

• Addition of PVP to isolate the gold nanoparticles and keep it from clustering (stir for 24 hours)

• Centrifuge mixture twice and wash once with water• 15,000 RPM for 15 minutes

• Preparation of silica coating on AuNPs• 460 mL of isopropanol, 66 mL of deionized water, 12.8

mL of ammonia (stir for a few minutes)• Nanoparticles collected from centrifugation added to

solution• Addition of TEOS to create the silica outer layer

(mixture stirred vigorously for at least 6 hours)• Centrifugation

• Collect nanoparticles into one container and wash twice with water and once with ethanol• 15,000 RPM for 15 minutes

• Dry in oven for 24 hours between 80-85°C

Images above represent the synthesized gold nanoparticles with worm channels at various microscopic resolutions. The diameter of the gold was 25 nm and the diameter of the nanoparticles with silica was 131 nm.

Figure 1: Above shows the IR Spectra of gold nanoparticles before and after calcination

Figure 2: The graph to the left shows the UV-Vis analysis after calcination. The one peak indicates the nanoparticles are spherical.

0E+00

2.000E-01

4.000E-01

6.000E-01

8.000E-01

0 75 150 225 300

cubi

c ce

ntim

eter

s/g

Radius Area (Å)

Pore Volume (cc/g)dV (logr) (cc/g)

0E+00

2.500E-01

5.000E-01

7.500E-01

1.000E+00

0 75 150 225 300

Rel

ativ

e Pr

essu

re

Volume @ STP (cc/g)

Figure 3: Adsorption and desorption on surface of silica

Figure 4: Analysis of pore size distribution

1. Xiaoliang Fang, Cheng Chen, Zhaohui Liu, Pengxin Liu and Nanfeng Zheng. The Royal Society of Chemistry 2011. A cationic surfactant assisted selective etching strategy to hollow mesoporous silica spheres.2. Bea Perks. Chemistry World September 2010. Gold Fever.3. Soren K. Klitgaard, Andrew T. DeLa Riva, Stig Helveg, Rebecka M. Werchmeister, Claus H. Christensen. 2008. Aerobic Oxidation of Alcohols over Gold Catalysts: Role of Acid and Base.

-0.125

0

0.125

0.250

0.375

0.500

400 500 600 700 800 900

Abs

orba

nce

Wavelength (nm)

Peak at ~2800 shows N–H stretch

Peak at ~1100 shows silica

Peak at ~3500shows Si–OH stretch

Organic peak at ~3000 is gone

Peak at ~3500 shows some water in Si–OH

The results show that the synthesis of gold hollow mesoporous silica spheres was achieved in this experiment.The future perspectives are to test the results of the benzyl alcohol oxidation using gas chromatography along with using the catalyst in an oxidation of glycerol where the HPLC will be used to analyze the results.

Pore Radius dV(r) = 20.533 ÅPore Volume = 0.178 cc/g

Surface Area = 386.737 m2/g

• Preparation of Au@HMSS with Worm Channels• CTAB dissolved in 100mL of deionized water

• 0.5013g of dried nanoparticles dispersed in 100mL of deionized water by ultrasonification

• Suspended nanoparticle/water mixture added into CTAB solution (stir for 24 hours at 35°C)

• Centrifugation• Collect nanoparticles into one tube and wash 4 times

with water and twice with ethanol• 12,000 RPM for 12 minutes

• Dry in oven between 80-85°C• Calcination

• Heat at 550°C for 360 minutes• Speed of heating increase 1°C per minute (start from

27°C)

• Oxidation of Benzyl Alcohol• 5mg of catalyst • 10 mL of benzyl alcohol• Temperature:160°C • Pressure: 5 bars of oxygen• Duration: 6 hours