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ACS Symposium: Finding Alternatives to Critical Materials in Photovoltaics and Catalysis from an Academic and Industrial Perspective
1. Finding Alternatives to Critical Materials In
Photovoltaics and Catalysis
Part II: Industrial Perspective
Jim Stevens and Harry A. Atwater
Corporate Fellow Howard Hughes Professor
Core Research & Development Applied Physics
The Dow Chemical Company Caltech
August 21, 2012
2. Strategic Elements
Strategic material - properties are essential to
nation, performs a unique function, and no viable
alternative exists.
Critical material – Strategic material with
significant risk of supply disruption.
Prediction of future demand is difficult -
distribution of metal use changes with time as
demands change.
Digital photography - huge reduction in demand for
silver for film since 2000.
Silver for PV contacts and thin fibers in socks to
counteract odors more than compensated Ag demand.
Slide 2
3. Criticality Depend on Timescale
Source - DOE “Critical Materials Strategy” report, 2010.
Other sources include Pt-group (Pt,Pd, Rh, Ir, Ru, Os)
Slide 3
4. Issues in Finding Alternatives to
Critical Materials in Catalysis
Slide 4
5. Context – Homogeneous / Heterogeneous Catalysts
Heterogeneous Homogeneous
Product/catalyst separation is More selective / high reaction
easy rates.
More stable / high reaction Can design complex structures
temp. possible. for specific jobs.
Challenging to study. Amenable to study and rational
Poor degree of synthetic design.
control. Limited to lower reaction
temperatures.
Opportunities Opportunities
Rational design of sophisticated New reaction mechanisms.
Het. cats. High throughput techniques.
Emissions catalysis.
Slide 5
6. Context – Catalysis in Chemical Industry
Catalysts produce many moles of product per mole
of catalyst (productivity) ⇒ used in small amounts
Catalysts have very high rates of reaction (turn-over
frequency) ⇒ used in small amounts.
>2,000,000 t/o; 600,000 h-1 tof1
Largest application of asymmetric catalysis
~10,000,000 Kg/y requires ~5 Kg Ir (assumes no recycle)2
(0.1% of 2010 Ir imports)
1 H.U. Blaser, et al., Chimia 53 (1999), 275. 2 Calculated from data in Blaser, Adv. Synth. Catal. 2002, 344, 17. Slide 6
7. Ligand Cost Can Dominate Catalyst Cost
Enantioselective homogeneous hydrogenation
catalyst.
Ir represents < 30% of catalyst cost.*
Generally metal can be recovered but ligands can not.
* Calculated from data in Blaser, Adv. Synth. Catal. 2002, 344, 17 and spot market price of Ir on 9/15/2011 Slide 7
8. Ligand Cost Can Dominate Catalyst Cost
Ethylene copolymerization, Isotactic polypropylene Enantioselective
EPDM catalyst catalyst hydrogenation catalyst
Ti ~ 0.05 – 0.5% of total Zr ~ 0.05 – 0.5% of total Rh < 15% of total catalyst
catalyst cost1 catalyst cost1 cost2
Metal Spot Market $/Kg
• Pt $57,544 • Os $13,404 • Au $54,480
• Pd $23,044 • Co $37 • Ag $1,280
• Rh $59,707 • Ni $22 • Zr $50
• Ir $37,038 • Ti $10 • Ru $5,997
1 Calculated from data in Metallocene Monitor and spot market metal price on 9/15/2011. 2 P. Moran, Dow Chemical, personal communication. Slide 8
10. Issues With Catalysts in Refineries
Refineries use enormous quantities of
catalysts – millions of Kg.
FCC units crack ~2x109 L/day of ~C14-C42
Reforming, isomerization reactions – Pt, Pd.
PGM’s can be considered as working capital.
Metals price can swing significantly, affecting
earnings.
Limitations on supply of some particularly
rare elements for such large volume
catalysts.
Potential opportunity for non-PGM catalysts.
Slide 10
11. Hydrosilylation Catalysis
4-6 MT of Pt (as metal) per year is consumed in cured silicones
and “lost” with the product*- $252M - $377M at 9/15/2011 price.
Additional 0.8 – 1.2 MT Pt used in silane / organofunctional
silicone, high % recycled.*
Mechanism credit to T. Don Tilley, UC Berkeley * Richard Taylor, Dow Corning Corp., personal communication
12. Potential Opportunities in Hydrosilylation Catalysis
Desirable improvements:
Pt $57,000 / Kg*
Lower cost catalysts ($ / Kg product), especially for Pd $23,000 / Kg
cured elastomers. Ni $22 / Kg
Need to meet critical performance requirements to be
commercially viable (kinetics, “snap cure”, chemo-
selectivity, environmentally benign, etc.).
Higher selectivity (regio-, chemo-, enantio-).
Potential approaches:
Identify new silane, olefin activations
Identify new mechanisms for hydrosilylation (e.g., mechanisms that
do not require a 2-electron redox process)
High-throughput discovery
Slide prepared with T. Don Tilley, UC Berkeley * Spot price, 9/15/2011 Slide 12
13. Acetic Acid
5 million MT y-1 produced by catalytic carbonylation of
methanol (2nd largest use of homogeneous catalysis).
1963 – BASF Co2(CO)8 catalyst
1970 – Monsanto [I2Rh(CO)2]- catalyst
1990’s – BP Cativa process [I2Ir(CO)2]- / Ru promoter -
~350 KTPa plant
2000’s – Celanese AO+ process – Rh / better I and
H2O management - ~800 – 1,200 KTPa plant, lower
capital
Slide 13
14. Cativa Acetic Acid Process (BP)
Runs in same plant as Monsanto
Rh-based process.
Lower H2O in process – lower
capital from fewer drying columns
Higher selectivity
Lower propionic acid
Suppresses water-gas shift
reaction
Ir – a “non-critical” PGM?
Acetic acid synthesis may not be a good opportunity
for future research.
Slide 14
15. Assemblies AERIFY* Monoliths AERIFY*
Advantages of diesel
• High performance & High torque • Emissions catalysis consumes 81%
• Durability & Reliability At least 500,000 miles life of PGM imports.
• Low maintenance • CeO2 also used as oxygen buffer /
• Fuel Economy 30% better than gasoline engine NOx reduction.
• Low gas emission (HC, CO, NOx) • Some Pt can be substituted with Pd,
• Low CO2/mile (GHG) Rh.
Disadvantages
• PM emission
• Difficult to reduce NOx by existing catalyst
technology
* Registered Trademark of The Dow Chemical Company Slide 15
16. Opportunities for Emissions Catalysis
Non PGM catalysts
Cannot form volatile compounds with CO (i.e.,
Ni)
Need to meet critical performance
requirements / legislated standards.
Cu cannot be used in N.A.
Better NOx catalysts, especially for diesel
particulate filters, new filter structures.
Slide 16
17. The LP OxoSM Process
• 1975 - UCC commercialised Rh-PPh3 catalyst
- Low pressure (17 bar) and temperature (90oC)
- 200 equivalents of PPh3 required
- n:iso ratio = 10
• 1995 - UCC commercialised Rh-bisphosphite catalyst
- 50 times more active than PPh3 system
- Lower pressure (7 bar) and temperature (75oC)
- n:iso ratio = 30
World production levels - 2.5 million mt.p.a. of 2EH
- 4.5 million mt.p.a. of butanols
- 95% made by Rh catalysed hydroformylation
Olefin hydroformylation is the largest volume homogeneous catalytic
reaction
Page 17
18. Potential Opportunities in Hydroformylation and
Enantioselective Catalysis
Desirable improvements:
Higher chemoselectivity and/or functional group tolerance
Need to meet critical performance requirements to be
commercially viable (kinetics, overall catalyst cost including ligand,
stability, sensitivity, safety, etc.).
Enantioselective catalysts with high rates and TON for addition
reactions to C=O bonds
Aldol reaction, Ene reaction, addition of MR to RCHO, Hetero Diels-
Alder, addition of CN- to C=O.
Enantioselective catalysts with high rates and TON for cross-coupling
and metathesis reactions.
Potential approaches:
Identify new mechanisms.
High-throughput discovery methodologies
New ligand families.
Slide 18
19. Issues in Finding Alternatives to
Critical Materials in Photovoltaics
Slide 19
20. Why Does Chemical Industry Care About PV?
Chemical Industry is a large consumer of
electricity/energy
Dow Chemical uses as much electricity as Australia, and
~1x106 barrels of oil equivalent per day.
Huge addressable market.
Worldwide electricity consumption: 20 PWh / $2 Trillion
Low market penetration - Oct 2011 US PV electricity: 169
GWh from total of 309,279 GWh (0.05%) (US EIA)
Technological materials-based solution with rapidly
changing & disruptive economics.
At inflection point for economic viability
Plastic, adhesives, encapsulants, wafer processing
chemicals, etc. supply.
Slide 20
21. 2010 - 2011 Solar Sector Dynamics
Enormous capacity build (2H 2010-1H 2011), especially in China.
2 Demand “shocks” from austerity measures and subsidy cuts
Italy Q4 2010-Q3, 2011. 100
Germany Q1-Q2 2011.
Module Sales Price, $/W
Inventories soared, prices collapsed >50%1 10
$0.80 - $1.00 per Wp module Today
Resulting shakeout of non-competitive 1
technologies.
Spectacular and highly politicized solar 0.1
module manufacturer bankruptcies. 1980 2000 2020
Solyndra, Evergreen Solar, SpectraWatt, Energy Conversion Devices,
Uni-Solar Ovonic, Q-Cells
1. Axiom Capital report, and A. Goodrich, Sr. Analyst NREL, personal communication. Slide 21
22. Two Electricity Delivery Architectures
Centralized Grid-Tied Distributed
Generation cost Generation cost
+ Connection fee + Connection fee
+ Transmission cost
+ Utility profit = Cost to consumer
+ Taxes & fees
Your view of PV electricity depends on which side of
the electric meter you are on (consumer vs. producer)
= Cost to Consumer
Slide 22
23. US Electricity Consumption Rises Steeply below
$0.18/kWh
• PV electricity cost is a function
of capital ($/W), lifetime,
interest rate & average
insolation.
• Average US insolation is
4.8kWh / m2 * day. (NREL).
• PV electricity value at $0.118 /
kWh (US residential average)
$2/w $3/w $4/w ranges from $0.06 / m2 * day
(10% efficient) to $0.59 / m2 * day
(100% efficient) at average US
insolation.
• Current PV market penetration
– 0.05% of total US electricity
At $2/W total installed cost, >$1.5 trillion of production.
demand potentially economically served by .Source - US EIA, Oct 2011
residential PV.
Slide 23
24. 4 Key Obstacles to Widespread Residential Solar Adoption
1. Installation complexity
2. Aesthetics
3. Price
4. Warranty concerns
The Opportunity:
Dow set out to design a cost effective, easy to install,
and aesthetically appealing roofing material that both
generates electricity and withstands elements for 20+
years
Total residential rooftop area available
for PV systems in US: 6.4 billion m2
(total area of Delaware)
This would provide 7.0 EJ/yr with 20%
modules (50% total US demand)
Rooftop Area from Navigant Consulting Slide 24
25. POWERHOUSE™ Photovoltaic Shingles
Core R&D/Energy/Dow Dow Plastics /Specialty Films Dow Building Solutions
Wire& Cable PV packaging BIPV commercial roofing
Thin film processing Back sheet, low-cost injection molding BIPV residential roofing
Mfg. process optimization
Materials Science expertise
Top layer
Wire & Cable business
Encapsulant
Back sheet
27. Caltech/Dow Earth Abundant PV Project
Combining the R&D strengths of Dow and Caltech to create a powerful
alliance for innovation in the field of Photovoltaics
Focus on development and commercial implementation
of PV materials that are inexpensive and earth
abundant such as Zn3P2 and Cu2O
from P.H. Stauffer et al Rare Earth Elements – Critical Resources
for High Technology, USGS (2002)
28. Summary
Most industrial chemical processes are very
efficient users of PGM’s and other critical metals
Emissions catalysis is a significant opportunity &
consumes significant amounts of PGM’s.
Hydrosilylation catalysis consumes ~2-4% of
annual Pt imports (2010 basis).
Alternatives to critical materials must meet
numerous critical performance requirements to
avoid significant economic impact.
Extension of thin-film PV technology to the
terawatt scale demands abundant materials and
high efficiency.
Slide 28