Finding Alternatives to Critical Materials In Photovoltaics and Catalysis Jim Stevens and Harry A. Atwater Corporate Fellow Howard Hughes Professor Core Research & Development Applied Physics The Dow Chemical Company Caltech August 21, 2012 Part II: Industrial Perspective
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ACS Symposium: Finding Alternatives to Critical Materials in Photovoltaics and Catalysis from an Academic and Industrial Perspective
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Finding Alternatives to Critical Materials In Photovoltaics and Catalysis
Jim Stevens and Harry A. Atwater
Corporate Fellow Howard Hughes Professor Core Research & Development Applied Physics The Dow Chemical Company Caltech
August 21, 2012
Part II: Industrial Perspective
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
Criticality Depend on Timescale
Other sources include Pt-group (Pt,Pd, Rh, Ir, Ru, Os)
Slide 3
Source - DOE “Critical Materials Strategy” report, 2010.
Issues in Finding Alternatives to Critical Materials in Catalysis
Slide 4
Context – Homogeneous / Heterogeneous Catalysts
Product/catalyst separation is easy
More stable / high reaction temp. possible.
Challenging to study. Poor degree of synthetic
control.
Opportunities Rational design of sophisticated
Het. cats. Emissions catalysis.
More selective / high reaction rates.
Can design complex structures for specific jobs.
Amenable to study and rational design.
Limited to lower reaction temperatures.
Opportunities New reaction mechanisms. High throughput techniques.
Slide 5
Heterogeneous Homogeneous
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)
Slide 6 1 H.U. Blaser, et al., Chimia 53 (1999), 275. 2 Calculated from data in Blaser, Adv. Synth. Catal. 2002, 344, 17.
Generally metal can be recovered but ligands can not. Slide 7 * Calculated from data in Blaser, Adv. Synth. Catal. 2002, 344, 17 and spot market price of Ir on 9/15/2011
Ligand Cost Can Dominate Catalyst Cost
Ethylene copolymerization, EPDM catalyst
Ti ~ 0.05 – 0.5% of total catalyst cost1
Slide 8 1 Calculated from data in Metallocene Monitor and spot market metal price on 9/15/2011.
Advantages of diesel • High performance & High torque • Durability & Reliability At least 500,000 miles life • Low maintenance • Fuel Economy 30% better than gasoline engine • Low gas emission (HC, CO, NOx) • Low CO2/mile (GHG)
Disadvantages • PM emission • Difficult to reduce NOx by existing catalyst
technology
• Emissions catalysis consumes 81% of PGM imports.
• CeO2 also used as oxygen buffer / NOx reduction.
• Some Pt can be substituted with Pd, Rh.
Slide 15 * Registered Trademark of The Dow Chemical Company
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
Page 17
The LP OxoSM Process
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
• 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
Potential Opportunities in Hydroformylation and Enantioselective Catalysis
Desirable improvements: Higher chemoselectivity and/or functional group tolerance Need to meet critical performance requirements to be
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
Issues in Finding Alternatives to Critical Materials in Photovoltaics
Slide 19
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
Your view of PV electricity depends on which side of the electric meter you are on (consumer vs. producer)
US Electricity Consumption Rises Steeply below $0.18/kWh
Slide 23
• PV electricity cost is a function of capital ($/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) 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 production. At $2/W total installed cost, >$1.5 trillion of
demand potentially economically served by residential PV.
$2/w $3/w $4/w
.Source - US EIA, Oct 2011
4 Key Obstacles to Widespread Residential Solar Adoption
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
Rooftop Area from Navigant Consulting
This would provide 7.0 EJ/yr with 20% modules (50% total US demand)
Total residential rooftop area available for PV systems in US: 6.4 billion m2
(total area of Delaware)
POWERHOUSE™ Photovoltaic Shingles
Core R&D/Energy/Dow Wire& Cable Thin film processing Mfg. process optimization Materials Science expertise Wire & Cable business
Dow Plastics /Specialty Films PV packaging Back sheet, low-cost injection molding
Dow Building Solutions BIPV commercial roofing BIPV residential roofing
Price could be the limitation (Rare = expensive) Supply & demand are difficult to predict
$0 $50
$100 $150 $200 $250
1990 1995 2000 2005 2010 2015
Te, U
S$/K
g
Tellurium
0 200 400 600 800
1000 1200
1990 1995 2000 2005 2010 2015
In, U
S$/K
g
Indium
Indium (ITO)
Tellurium (CdTe), Indium (CIGS)
Silver (ECA)
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)
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.