1. Results
20 30 40 50 60 70 80
Intensity
2θ (degrees)
RuO2 Peaks
Ru Peaks
900°C
700°C
500°C
350°C
Ox50
20 30 40 50 60 70 80
Intensity
2θ (degrees)
Pt3O4 Peaks
Pt Peaks
900°C
700°C
500°C
350°C
Ox50
20 30 40 50 60 70 80
Intensity
2θ (degrees)
RuO2 Peaks
Ru Peaks
900°C
700°C
500°C
350°C
A380
20 30 40 50 60 70 80
Intensity
2θ (degrees)
Pt3O4 Peaks
Pt Peaks
900°C
700°C
500°C
350°C
A380
The Effect of Catalyst Support Structure on
Nanoparticle Thermal Stability
Morgan Sulzbach1, Qiuli Liu2, Andrew Wong2, Dr. John Tengco2, Dr. J.R. Regalbuto2
1Department of Chemical Engineering, University of Maryland, College Park
2Department of Chemical Engineering, University of South Carolina
Conclusions
Significance
• Use in future catalyst design to
improve efficiency and affordability
of fuel cells, renewable fuels, and
environmental remediation1.
Future Directions
• Investigate the differences seen in
Pt and Ru thermal stability.
• Determine the effect of structure on
nanoparticle size after other
techniques such as steam reduction.
• Collaborate with computational
researchers to understand the
mechanism of catalyst stability.
References
1. J. M. Campelo, D. Luna, R. Luque, J. M. Marinas and A. A.
Romero, ChemSusChem., 2009, 2, 18.
2. J.R. Regalbuto (Ed.), Catalyst Preparation: Science and
Engineering, Taylor and Francis/CRC Press, Boca Raton, FL
(2007), p. 161.
3. Q. Liu, U.A. Joshi, K. Über, and J.R Regalbuto, Phys. Chem.
Chem. Phys., 2014, 16, 16431.
Acknowledgements
• National Science Foundation for funding the Research
Experience for Undergraduates Program
• USC Department of Chemical Engineering for hosting the
program
• My mentors listed above and all members of the lab who
have helped me throughout the summer
Methods
Uptake Surveys
Find pH with optimal
uptake.
Catalyst Batch
Prepare a batch at
optimal pH.
Reduction
Reduce in H2 for 2 hours
at different temperatures.
X-Ray Diffraction
Calculate nanoparticle
size.
1.8 1.8
2.0
3.4
1.9 1.9
1.7
4.2
350°C 500°C 700°C 900°C
Pt/A380 Pt/Ox50
Introduction
• Supported metal catalysts have
widespread applications in chemical
processes1.
• Strong electrostatic adsorption
(SEA) suspends the support in a pH-
controlled, metal ion solution to
obtain optimal monolayer
adsorption.
Figure 1. SEA controls pH to protonate or
deprotonate hydroxyl groups on the support’s
surface. The resulting charge allows adsorption of
metal complexes2.
Figure 3. Metal surface density vs. final pH of solution at 1000 m2/L. (A) Platinum tetraammine
([Pt(NH3)4]2+); (B) Ruthenium hexaammine ([Ru(NH3)6]3+) on Aerosil-380 and Aerosil-Ox50.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
4 6 8 10 12 14
SurfaceDensity(μmol/m2)
Final pH
A380
Ox50
B. RuHA
0
0.2
0.4
0.6
0.8
1
1.2
4 6 8 10 12 14SurfaceDensity(μmol/m2)
Final pH
A380
Ox50
A. PTA
Uptake Surveys
XRD Analysis
SBA-15
Structured
Mesoporous
A380
Amorphous
Mesoporous
Ox50
Amorphous
Nonporous
OH
OH2
+
O-
PZC
pH<PZC
pH>PZC
[PtCl6]2-
[(NH3)4Pt]2+
[H]+
(pH shift)
Previous Research
Figure 2. XRD plot from previous research3 with
7.6 wt% Ru on SBA-15.
BLD BLD BLD
1.4
2.0
2.5 2.7
5.8
2.1
2.4
0.8
3.2
350°C 500°C 700°C 900°C
Ru/SBA-15 Ru/A380 Ru/Ox50
Figure 4. XRD plots of (A) Pt/A380 (5.6 wt%, 0.9 μmol/m2); (B) Pt/Ox50 (0.8 wt%, 1.0 μmol/m2); (C)
Ru/A380 (5.1 wt%, 1.6 μmol/m2); (D) Ru/Ox50 (0.7 wt%, 1.7 μmol/m2).
Figure 5. Summary of (A) Pt and (B) Ru particle sizes in nanometers. Columns denoted with “BLD” had
particle sizes below the limit of detection.
A. Pt/A380 B. Pt/Ox50
C. Ru/A380 D. Ru/Ox50
A. Pt B. Ru
SBA-15
Structured
Mesoporous
Pt Ru
A380
Amorphous
Mesoporous
Ox50
Amorphous
Nonporous
More stable
Less stable