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IEA Topical Meeting, Berlin, Nov. 15th, 2017
Lior ElbazIsraeli Fuel Cells Consortium (Head)
Bar-Ilan University, Ramat-Gan, Israel lior.elbaz@biu.ac.il
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Motivation
Accelerating the development of PGM-free electrocatalysts for next-generation fuel cells
IEA Topical Meeting, Berlin, Nov. 15th, 2017
PGM-free catalysts are a key research goal for moving towards DOE’s ultimate$30/kW target (D. Papageorgopoulos, Annual Merit Review and Peer Evaluation Meeting,
Washington, DC, June 5-9, 2017)
Motivation
IEA Topical Meeting, Berlin, Nov. 15th, 2017
US-DOE Technical Targets
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Biology
Oxygen Reduction Reaction (ORR)
Fuel Cells
5
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Unsolved Problems in Electrocatalysis of Oxygen Reduction
Low Turnover Frequencies
Thermodynamic Barrier (Pt)
H. Gastieger et al., Science, 2009, 324,48.
I. Stephens et al., Energy Environ. Sci., 2012, 5, 6744.
Stability
Elbaz et al., J. Power Sources, 2016
U.S. Geological Survey Fact Sheet 087-02 (2002)
Low abundance of precious metals
Turnover Frequencies
Thermodynamic Barrier (Pt)
H. Gastieger et al., Science, 2009, 324,48.
I. Stephens et al., Energy Environ. Sci., 2012, 5, 6744.
Stability
Elbaz et al., J. Power Sources, 2016
Low abundance of precious metals
U.S. Geological Survey Fact Sheet 087-02 (2002)U.S. Geological Survey Fact Sheet 087-02 (2002)
6
IEA Topical Meeting, Berlin, Nov. 15th, 2017J.P. Collman et al., J. Am. Chem. Soc., 2002
Precious Group Metal-Free ORR Catalysts
J-P. Dodelet et al., Nature Comm., 2011P. Zelenay et al., Science, 2011
MolecularPyrolyzed
R. Jasinski, Nature, 1964, 201, 1212
Pyrolysis Sophisticated synthesis
Activity
StructureStability
Synthesis
Pros
Cons
Activity
Structure
Pros
Cons
Stability
Synthesis6
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Sub groups of PGM-free ORR catalysts for PEMFCs
PGM-Free Pyrolyzed M-N-C
Metal-Organic Frame works
Macrocyclic compounds
Molecular
Enzymatic
Macrocyclic compounds
Bio-mimetic
Metal-free???
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964
IEA Topical Meeting, Berlin, Nov. 15th, 2017
2e- reduction to H2O2:
Co(III)P + e- Co(II)P
Co(II)P + O2 Co(III)P __ O2.-
Co(III)P __ O2.- + 2H+ Co(III)P + H2O2
Consecutive reduction of H2O2 to H2O:
Co(III)P + e- Co(II)P
Co(II)P + H2O2 Co(III)P __ H2O2.-
Co(III)P __ H2O2.- + 2H+ Co(III)P + 2H2O
Proposed ORR Mechanism – Electrochemical Chemical
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969
Jahnke, H.; Schoenborn, M.; Presses Acad. Eur: 1969, p 60-65.
1) Improved Activity
2) Improved Stability
3) Unknown structure!
Heat Treated Phthalocynines
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976
Jahnke, H.; Schonborn, M.; Zimmermann, G. (1976)
Organic dyestuffs as catalysts for fuel cells. Top Curr
Chem 61: 133-181.
IEA Topical Meeting, Berlin, Nov. 15th, 2017
b-Substituents
R2 =
Elec
tro
neg
ativ
ity
meso-Substituents
R1 =
Three Key Parameters
Metal Center
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976 1976-1980
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976 19801976-1980
Fukuzumi, S.; Okamoto, K.; Gros, C. P.;
Guilard, R. JACS 2004, 126, 10441.
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976 1980 1980-2000 2000-Today
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Biomimetic Electrocatalysis of Oxygen Reduction
Very active, very expensive and not so stable.
http://web.stanford.edu/group/collman/cco.htm
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976 1980 1980-2000 2000-Today
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Mn
Fe
Co
Ni
Cu
ORR Onset Potential (in acid) (V vs. RHE)
0.81
0.720.69
0.480.46
Electrocatalysis of ORR with Molecular Catalysts
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976 1980 1980-2000 2000-Today
van Veen, J. A. R.; van Baar, J. F.; Kroese, K. J. (1981) J Chem
Soc, Faraday Trans 1: Phys Chem in Condensed Phases 77
(11): 2827-2843.
Schulenburg, H.; Stankov, S.; Schünemann, V.; Radnik, J.;
Dorbandt, I.; Fiechter, S.; Bogdanoff, P.; Tributsch, H. (2003) J
Phys Chem B 107 (34): 9034-9041.
MN4/C Catalysts
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976 1980 1980-2000 2000-Today
Wu, G.; Chung, H. T.; Nelson, M.; Artyushkova, K.; More, K. L.;
Johnston, C. M.; Zelenay, P. (2011) ECS Trans 41 (1): 1709-
1717.
Li, X.; Popov, B. N.; Kawahara, T.; Yanagi, H. (2011) J Power
Sources 196 (4): 1717-1722.
IEA Topical Meeting, Berlin, Nov. 15th, 2017
1964 1969 1964 - 1976 1980 1980-2000 2000-Today
J.Y. Cheon et al., Nature 2013 (3) 2715
IEA Topical Meeting, Berlin, Nov. 15th, 2017
State-of-the-Art - Pyrolyzed
MOFs M-N-Cs
P. Zelenay, annual merit review presentation 2016 D.J. Liu et al., ChemElectroChem, 2016, 3, 1541
IEA Topical Meeting, Berlin, Nov. 15th, 2017
H. Gastieger et al., Science, 2009, 324,48.
Catalytic Site Density, is this the Answer?
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Durabilty
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Co(III)P + e- Co(II)PCo(II)P + O2 Co(II)-O2
Co(II)-O2 + 3e- + 4H+ Co(III) +H2O
Stable
Not Stable
Catalyst Degradation Mechanism
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Solution: Molecular Catalysts as Model Structures
Characterization
SynthesisModelling
Design
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Future Work
Catalyst Activity:
• Increase site density• Tune porosity to enhance mass transfer• Understand structure-activity relationship
Durability:
• Use durable non-carbon supports• Minimize and eliminate spectator species in Fe-based
catalysts• Improve durability by advance cathode design
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Commercialization: Pajarito Powder
Advisory Board
Prof. Piotr Zelenay
Prof. Plamen Atanssov
Prof. Sanjeev Mukerjee
Prof. Hubert Gasteiger
Prof. Scott Calabrese-Barton
Prof. J-P Dodelet
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Commercialization: Ballard-Nisshinbo
“platinum, which goes for some 4,000 yen ($36.35) per gram. Replacing it with a catalyst using Nisshinbo's carbon alloy, which costs less than 1 yen per gram”
Ballard has successfully incorporated the Non Precious Metal Catalyst into a high performing catalyst layer under a Technology Solutions program and plans to launch a new 30-watt FCgen®-1040 fuel cell stack product incorporating NPMC for commercial use in late-2017.
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Products: GenCell
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Conclusions
• PGM-free are needed in order to further reduce fuel cells price
• PGM-free catalysts can be divided into two major groups: Pyrolyzed and Molecular
• Pyrolyzed catalysts are considered to be the most active
• Durability and Site density are still big challenges
• Further development of 3D networks is showing great promise
• Industry has began adopting PGM-free catalysts and use them in commercial fuel cells
IEA Topical Meeting, Berlin, Nov. 15th, 2017
Thank you!
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