novel approach to non-precious metal catalysts
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Novel Approach toNon-Precious Metal Catalysts
Radoslav T. Atanasoski3M CompanyMay 15, 2007
Project ID#: FC 4
2007 DOE HYDROGEN PROGRAM REVIEWMay 15 -18, 2007, Washington, DC
This presentation does not contain any proprietary, confidential, or otherwise restricted information
Overview
Timeline• Project start date: September 1,
2003• Project end date: August 31, 2007• Percent complete: ~95%
Budget• Total Project funding: $3.6 million
- DOE: $2.9 million- Contractor: $0.7 million
• Funding received in FY06: $967 K• Projected funding for FY07: $343 K
Barriers• B. Cost• C. Electrode Performance (Technical targets: See next slide)
Partners/Collaborations• Dalhousie University (subcontractor)
- Prof. J. Dahn; High-throughput catalyst synthesis and basic characterization
• Brookhaven National Lab- Dr. X.-Q. Yang and Dr. W.-S. Yoon; X-Ray
Absorption Spectroscopies • University of Missouri – Kansas City
- Prof. D. Wieliczka; UPS at University of Wisconsin Synchrotron Radiation Center
• INRS-Energie, Materiaux et Telecommunications
- Prof. J-P. Dodelet; EXAFS and UPS characterization of the “model” catalyst
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 23M
Objectives
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 3
Goal: Develop new, lower-cost, non-precious metal (NPM) cathode catalysts for replacement of Pt in PEM fuel cells.
Objectives:• Reduce dependence on precious metals (Pt).
• Perform as well as conventional precious metal catalysts currently in use in MEA’s.
• Cost 50% less compared to a target of 0.2 g Pt/peak kW.
• Demonstrate durability of >2000 hours with <10% power degradation.
Non-Pt Catalyst Activity per volume of supported catalyst at 800 mVIR-free
Specific Objectives for 2007 (From last year’s future work slide, FC#12):
Produce new, better-performing more durable catalysts and identify the catalytic sites.
2010 > 130 A/cm3
2015 300 A/cm3
Current DOE Targets:(from HFCIT Multi-Year R&D Plan)
3M
Approach
New materials
Vacuum Nanotechnology
Modeling
Catalyst SynthesisPhysicochemical Characterization
• XPS• XRF• SEM• XRD• Modeling• Ellipsometry• XAS (Brookhaven National Lab)
• SIMS• UPS
Functional Characterization
• Fuel Cell- 50 cm2
(performance and durability)
- Segmented• Gas Diffusion Electrode
• RRDE
• Catalyst synthesis carried out via two complementary and interactive approaches both readily scalable to pilot plant level: Vacuum Processes and Nanotechnology.
• Extensive physicochemical analytical characterization, including modeling work, conducted both at 3M and in collaboration with other institutions when appropriate.
• Functional characterization chiefly performed in 50-cm2 FC; other techniques as required.
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 43M
• Achieved durability of over 1,000 hours with practically no irreversible performance losses− with comparable, state-of-the-art NPM catalyst activity as reported in
the literature,
− tested at 0.65 V under Hydrogen – Air in 50-cm2 fuel cell.
• Catalytic activity 0.1 A/cm2 at 0.77 V approached the Interim Milestone #5 (0.1 A/cm2 at 0.8 V).
• Fabricated higher surface area, thermally stable substrates for use with the vacuum approach. Achieved activity surpassing the best previous result by a factor of four.
• Made advances in testing, characterization, and modeling that provide valuable feedback for materials development.
Technical Accomplishments
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 53M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 6
Nanotechnology – Durable Catalyst Support
0 20 40 60 80 100 120 1400.00
0.02
0.04
0.06
0.0875C cell, 30/30 psig, H2/airCF500/500 sccm, coflow.Humidity: 100%/100%
J (A
/cm
2 ) at 0
.6 o
r 0.6
1V
Time at 0.6 or 0.65V (hours)
0 100 200 300 400 500 600 700 800 900 10000.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
75ºC cell, 30/30 psig, 500 sccm H2/500 sccm air, 100%/100%;Current measured at 0.6V from polarization curve after 5 hour hold at 0.65V
FC11925-graph9
J at
0.6
V or
0.6
1V (A
/cm
2 )
Time (hours)
FC11137 FC11138 FC11168 FC11169 FC11909Higher initial performance
More durable (higher Jafter ~66 hours)
Performance of the catalyst supported on dispersed carbon is initially the best but decays rapidly.
Materials different than dispersed carbon, conducting and electrochemically stable in fuel cell environment, were introduced as catalyst support. Performance of these catalysts is very stable and equals the best reported elsewhere. (see next slide)
TiC Support
Higher J after ~ 66 hoursStable performance for > 1,000 hours
Higher initial performance on dispersed carbon
Dispersed Carbon Support
(See Back - up slides for nature of the catalyst)
3M
Under AIR
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 7
LANL recently published a paper in Nature detailing a new catalyst, which shows 100 hrs durability. Under similar test conditions, 3M’s catalyst after 1005 hours and LANL’s initial performance are comparable.
Durability – Performance Comparison
0.00 0.02 0.04 0.06 0.08 0.100.4
0.5
0.6
0.7
0.8
0.9
1.0
V (V
olts
)
J (A/cm2)
3M (FC11909, After 1005 hours) LANL
LANL - 5 cm2 cell; 80ºC, 30/30 psig, 300 sccm H2/540 sccm O2, CDP90C/CDP80C; Bashyam and Zelenay, Nature, Vol 443, 7 September 2006, 63, supp. info.3M - 50 cm2 cell; 80ºC cell, 30/30 psig, 560 sccm H2/1000 sccm O2, CDP90C/CDP80C
LANL - 5 cm2 cell; 80ºC, 30/30 psig, 300 sccm H2/540 sccm O2, CDP90ºC/CDP80ºC; Bashyam and Zelenay, Nature, Vol 443, 7 September 2006, 63, supp. info.
3M - 50 cm2 cell; 80ºC cell, 30/30 psig, 560 sccm H2/1000 sccm O2, CDP90ºC/CDP80ºC
3M
Under OXYGEN
Durable Substrate – Surface Area Effect
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 8
CVs under NitrogenThe substrate – TiC treated the same way without the catalyst.
The surface area increased by a factor 3 – 4.
The ORR activity in the presence of the catalyst is
orders of magnitude higher.
FC Performance under Oxygen
0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.012
-0.008
-0.004
0.000
0.004
0.008
0.012
I (A
/cm
2 )
E (Volts)
FC11909 - TiC FC11925 - TiC ink sonicated FC12027 - milled TiC FC12056 - BASELINE - TiC fired only (no NA)
Summary_TiC_SiC-graph3
0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02
Summary_TiC_SiC-graph4
I (A
/cm
2 )
E (Volts)
FC11909 - TiC FC11925 - TiC ink sonicated FC12027 - milled TiC FC12056 - BASELINE TiC fired (no NA)
3M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 9
Durable Substrate – Voltage StabilityPS held at 1.2V, 1.4V, and 1.5V for 10
minutes; then repeated (1.2V, 1.4V, 1.5V); 75ºC, N2, 132%/132%RH.
0 300 600
10-3
10-2
T ime (Sec)
I (Am
ps/c
m2 )
PS_1.2V_10min_Un2Ch4.corPS_1.4V_10min_Un2Ch4.corPS_1.5V_10min_Un2Ch4.corPS_1.2V_10min_Un2Ch4.corPS_1.4V_10min_Un2Ch4.corPS_1.5V_10min_Un2Ch4.cor
N2 CVs (50 mV/s) – Initial, After 1.2V,1.4V, and 1.5V for 10 min and after additional 10 min at 1.2V, 1.4V, and 1.5V
0 0.2 0.4 0.6 0.8 1.0 1.2-0.4
-0.2
0
0.2
0.4
E (Volts)
I (Am
ps/5
0 cm
2 )
InitialAfter 1.2V, #1After 1.4V, #1After 1.5V, #1After 1.2V, #2After 1.4V, #2After 1.5V, #2
The new substrate material – TiSi – is stable up to 1.4 V. Only after second exposure at 1.5 V, for a total of 20 minutes, considerable surface area effect is observed.
3M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 10
Durability – Other Catalyst PropertiesLarger hydrogen evolution peak (in the N2 CVs) showed greater durability.
N2 CVs (50 mV/s)
0 100 200 300 4000.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
Nor
mal
ized
Cur
rent
(J/J
initi
al) a
t sta
ted
volta
ge
Time (hours)
FC11909 Normalized FC12178 Normalized FC12245 Normalized FC12172 Normalized
Normalized durability current
0.000 0.005 0.010 0.015 0.020 0.0250.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
1-J/Jinit (50hours, 1)
1-J/
J initi
al (5
0 ho
urs
afte
r J/J
i=1)
Intensity of hydrogen evolution peak (A/cm2)
This may point to surface properties of the catalyst that are essential for durability.
0 0.2 0.4 0.6 0.8 1.0 1.2-0.020
-0.016
-0.012
-0.008
-0.004
0
0.004
0.008
0.012
E (Volts)
I (A
mps
/cm
2 )
FC12245FC12172FC11909FC12178
Intensity of H2 evolution peak
Durability
3M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 11
Durability – Peroxide Content
0 0.2 0.4 0.6 0.8 1Potential vs. RHE [V]
-5
-4
-3
-2
-1
0
Dis
k C
urre
nt D
ensi
ty [m
AFa
rada
ic. c
m-2
geom
etri
c]
10
20
30
40
50
60
70
80
90
100%
H2O
2
b)
a)
00-38-1
00-41-2
3M Samples at 900 rpm0.1 M HClO4, room temp
5 mV.s-1, 785μg.cm-2
December 2006
00-38-1
00-41-2
RRDE studies performed on three different catalysts at Dalhousie University.
• Peroxide emission of best performing catalyst on TiCsubstrate is relatively low (< 10%).
• Same peroxide content on the same catalyst made on carbon substrate did not result in durable product.
3M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 12
Thermal Treatment – The Role of Iron
Thermal treatments to 550ºC, 700ºC, and 900ºC in ammonia were performed on three aliquots of the same catalyst batch.
J (m
A/c
m2
) at
0.6
V (
O2
)
252015
30
20
10
0
Treatment Temp (C)
Fe r
edox
(m
A/c
m2
)
1000750500
8
7
6
5
4
Fe (XRF, arb units)
• Performance increases with thermal treatment temperature, NOT THE AMOUNT OF IRON.
•Nearly 1:1 correspondence of Fe content measured via XRF vs the intensity of the Fe redox in the N2 CVs.
• Most Fe remains on the sample treated to 700OC.
3M
Vacuum Processes – New Substrates
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 13
• Performance of the new catalyst is significantly better than the best 2006 results from the vacuum approach.
New higher surface area, thermally stable substrates (developed at 3M expense, utilizing 3M proprietary technology) were further improved.
ORR activity of the new substrate with vacuum deposited Fe catalyst
CVs under nitrogen of the new substrate show a large increase in surface area
0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02 2006 Review 2007 Review
I (A
/cm
2 )
E (Volts)
80C Cell, 30/50 psig, CDP80/CDP80;CF180 H2/CF335 O2; CVs at 5 mV/s
0.0 0.2 0.4 0.6 0.8 1.0 1.2-0.006
-0.004
-0.002
0.000
0.002
0.004
I (A
/cm
2 )
E (Volts)
2006 Review 2007 Review
75ºC, 0/0 psig, CF500 H2/CF500 N2, 132%/132%RH
3M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 14
Vacuum Processes – Thermal Treatment
The loss of nitrogen is accompanied by a transition from homogeneity to heterogeneity in the material structure which is reflected on ORR activity as measured by RDE. (Dalhousie University)
E. B. Easton, R. Yang, A. Bonakdarpour, and J. R. Dahn*, Electrochem. and Solid-State Lett., 10 1 B6-B10 2007600 650 700 750 800 850 900 950 1000
Heat-treatment Temperature(oC)
00.40.81.21.6
2
Cur
rent
den
sity
@0.
7V(m
A/c
m2 )
0.50.60.70.80.9
1
Ons
et P
oten
tial
(V v
s.R
HE)
10203040506070
Co
part
icle
siz
e (n
m)
510152025303540
Ato
mic
con
tent
of N
(%)
91011121314
Ato
mic
con
tent
of C
o(%
)
0.1M KOH 0.1M HClO4
0.1M KOH 0.1M HClO4
Nitrogen Loss Heterogeneity
3M
Future WorkRemainder of project:
• Fulfill reporting obligations, most notably the Final report.
• Prepare manuscripts for publication and conference presentations.
• Explore further the area of more durable catalysts substrates and identify the catalytic sites (will continue after completion of the Project).
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 153M
Summary
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 16
• In 2007, a major breakthrough in durability was achieved.
• Overall, the project established new synthetic approachesand opened new avenues for further development in the NPMC world.
• Strong interactive advanced characterization and modeling complement the synthetic effort.
• Strong, fully-integrated collaborations supplement 3M expertise and lead to fundamental understanding of catalyst.
• 12 publications, presentations, and three invited lectures.
• Today, 3M’s catalysts are among the best performing and most durable NPMC tested in a real fuel cell.
Performance ProgressionCurrent at 0.6 V in 50-cm2 FC
0 100 200 300 400 500 600 700 800 900 1000 1100 12000.000
0.004
0.008
0.012
0.016
0.020
0.024
0.028
FC11925-graph4
J at
0.6
V (A
/cm
2 )
Time (hours)
FC11909
Initial performance
Durability
1E-3 0.01 0.1 10.6
0.7
0.8
0.9
1.0 DOE targets calculated assuming same catalystlayer thickness as for the 3M curve shown.
3M: 80ºC cell, 30/50 psig, 100%/100%RHH2/O2; CF180/335 sccm. Pt: 80ºC cell, 7.5/7.5 psig, 100%/100%RH;CS(2.0,139) H 2/CS(9.5,331) O2. Gasteiger et al., Applied Catalysis B: Enviromental 56(2005) 9-35
3M, 19 A/cm3
DOE 2010130 A/cm3
V (V
olts
)
J (A/cm2)
Pt, 0.4 mg/cm2
70 mV/decade
DOE 2015300 A/cm3
DOE 2005 status 8 A/cm3
GM Benchmark Performance
Performance Status
0.01
0.1
1
10
100
1000
9/1/03 8/31/07Timeline
Cur
rent
at 0
.6V
(mA
/cm
2 )
VacuumNanotechnology
3M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 17
Highly Nitrogenated Carbon – HNC – for Acidic FC
• Requires low basicity of nitrogen sites• “Pyridinic” – higher basicity• “Pyrazinic” – lower basicity• Model compounds (Literature values):
N
N
N
N
pKa = 0.37pKa = 1.1N
N
pKa = 0.6
N
NN
pKa = 5.14 pKa = 4.85 pKa = 5.14
N
pKa = 4.52
Catalyst activity depends on the content and the basicity of the N sites:
3M
Novel Approach to Non-Precious Metal Catalysts – 2007 DOE Hydrogen Program Review, May 15 – 18 18
Thermal Polymerization to Form New HNC
•When iron or cobalt are present, metal is retained as bonded to nitrogen
•Further thermal processing increases conductivity
•Metal cation is used to retain active nitrogen sites (template)
•Metal can be removed with retention/enhancement of activity
•Can titrate sites to examine nitrogen density and basicity
•Supported on nanoparticle support for high surface area
NH2
NO2
NH2 NO2
+Cat.
Δ
NH2
O2N
NH2
O2N+
Cat.
Δ N
NN
Nn
N
N
N
N
N
N
n
(One possible configuration)
Nanoparticle support
Nanoparticle support
3M
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