Transcript Nanostructured Bimetallic, Trimetallic and Core

Nanostructured Bimetallic, Trimetallic and Core-Shell Fuel-Cell
Catalysts with Controlled Size, Composition, and Morphology
(NIRT CBET-0709113)
Jin
1
Luo ,
Peter N.
1
Njoki ,
1
Mott ,
1
Wanjala ,
1
Loukrakpam ,
1
Fang ,
Derrick
Bridgid
Rameshwori
Bin
Xiajing
Susan Lu2, Lichang Wang4, Bahgat Sammakia3, and Chuan-Jian Zhong1*,
1Chemistry, 2Systems
1
Shi ,
Khalid
2
Alzoubi ,
3Mechanical
Department of
Science and Industrial Engineering,
Engineering, State University of New
York at Binghamton; 4Department of Chemistry & Biochemistry, Southern Illinois University at Carbondale, USA
Abstract: Active, robust, and low-cost catalyst is a key component for the commercialization of fuel cells. The development of effective strategies for the synthesis and processing of multimetallic
nanoparticles with controllable size and composition is an important approach to the catalyst preparation. This poster focuses on the results from an investigation of bimetallic, trimetallic, and core-shell
nanoparticle catalysts for fuel cell testing. The characterization of the size, shape, composition and phase properties of the multimetallic nanoparticles and catalysts is described. The electrochemical
characterization of the electrocatalytic properties of the catalysts for fuel cell reactions is discussed along with preliminary evaluation of some of the catalysts under fuel cell testing conditions. The results
are also discussed in terms of activity and stability of the catalysts based on theoretical computation and statistical optimization to gain fundamental insights into the design and control parameters of fuel
cell catalysts.
Core-Shell Catalysts
Fuel Cell and Catalysts
• High conversion efficiency
• Low pollution
• Light weight
• High power density
HTEM-EDX analysis
Pt
V
Fe
Existing Catalysts:
• Low activity
• High Pt loading (high cost)
• Poor stability
Goals: • Reduce Pt loading
Fuel cell voltage:
Ecell = ENernst +
ηact (i.e., ηact(cathode) - ηact(anode)) – ηohmic
• Increase activity & stability
• Understand design parameters
• Discover new catalysts
Relative Mass Activities for ORR
Bimetallic Nanoparticles & Catalysts
Trimetallic Nanoparticles & Catalysts
DFT Calculations
XRD of AunPt100-n/C
Preparation of
PtVFe
Nanoparticles
Spot (size)
Pt
V
Fe
10 (area)
34
16
50
11 (3nm)
34
16
50
12 (3nm)
33
15
52
13 (6nm)
32
13
55
Composition
32
13
55
Bulk:
: data for bulk
bimetallic metal system
: frozen states of bulk
bimetallic metal system
EDX Analysis of
Composition
Fuel Cell Testing
Optimization Analysis
Fuel cell
polarization curves
of MEA with Pt/C
catalyst (20%
loading).
Pt loading: 1.0
mg/cm2, MEA
active area: 5 cm2.
Pareto optimization
Activity
+
PtNiZr
Comparison of relative electrocatalytic activities.
Examples: Pt32V14Fe54/C (31% loading),Pt31Ni34Fe35/C
(30% metal loading) and standard Pt/C (20% metal
loading) catalysts. Insert: Rotating Disk Electrode data
for catalysts on glassy carbon electrode in 0.5 M H2SO4.
(5 mV/s, and 2000 rpm).
Preliminary results from density functional
theory (DFT) calculations for O2 on
PtmVnFel and Pt nanoparticles show that
the oxygen reduction reaction is favorable
on PtmVnFel in comparison with Pt due to
direct or spontaneous O2 dissociations. O2
dissociation on PtmVnFel nanoparticles is
limited by the active sites (Pt-V or Pt-Fe)
available.
Optimal balanced
activity and
stability for
(Ni)x(Zr)yPt1-x-y
Stability
Selecting M1 and M2 can be based on Pareto optimization
plot. A set of solutions is said to be Pareto optimal if it cannot
be improved upon without hurting one of the objectives.
Summary
• Bimetallic, trimetallic, and core-shell nanoparticle catalysts with controlled size,
composition and phase properties have been shown to exhibit high electrocatalytic
activity.
• Experimental, theoretical, and statistic analysis results have shown that the size and
composition of multimetallic nanoparticles play an important role in regulating the
electrocatalytic activity and stability.
• These multimetallic nanocatalysts are being characterized and evaluated under fuel
cell conditions in terms of activity and durability.
: bimetallic composition
determined from XRD
: bimetallic composition
determined from DCP-AES.
FTIR of CO Adsorption on AunPt100-n/SiO2
Pt32 V14 Fe54 /C
General correlation between two different properties
(Activity and Stability) for catalyst (M1)x(M2)yPt1-x-y
ORR: Oxygen Reduction Reaction
Nanoscale:

Characterization of electrocatalytic
activity and stability of the multimetallic
catalysts using RDE technique
Evaluation of the activity and durability
of membrane electrode assembly
(MEA) in fuel cells
}
Support
References
1. Luo, J.; Wang, L.; Mott, D.; Njoki, P. N.; Kariuki, N. N.; Zhong, C. J. He, T., J. Mater. Chem., 2006, 16,
1665.
2. Luo, J.; Han, L.; Kariuki, N. N.; Wang, L.; Mott, D.; Zhong, C. J.; He, T., Chem. Mater., 2005, 17, 5282.
3. D. Mott, J. Luo, P. Njoki, Y. Lin, L. Wang, C. J. Zhong, Catalysis Tod., 2007, 122, 378
4. X. Shi, J. Luo, P. Njoki, Y. Lin, T. H. Lin, D. Mott, S. Lu, C. J. Zhong, Ind. Eng. Chem. Res., 2008, 47, 4675.
5. Zhong, C. J.; Luo, J.; Njoki, P. N.; Mott, D.; Wanjala B.; Loukrakpam, R.; Lim, S. I-I.; Wang, L.; Fang, B.; Xu,
Z., Energy & Environ. Sci, 2008, 1, 454.
6. J. Luo, L.Y. Wang, D. Mott, P. Njoki, Y. Lin, T. He, Z. Xu, B. Wanjala, S. I-Im Lim, C. J. Zhong, Adv. Mater.,
in press.
For More Information:
Optimization
and
Identification
of the best
catalysts
NIRT
Email Contact: * C.J. Zhong: [email protected]; Web: http://chemistry.binghamton.edu/ZHONG/zhong.htm