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http://www.ANSERCenter.org
New Fuels: Artificial Photosynthesis
Future Transportation Fuels StudyNational Petroleum Council
Victoria L. Gunderson and Michael R. WasielewskiApril 20, 2011
White Paper Outline
Motivation
What is Artificial Photosynthesis?
Current Technological Maturity
Players & Research
Challenges
Key Findings
Future Outlook
Global Energy: The Need
THE ENERGY NEED:• 13 TW in 2004• 30 TW in 2050• 45 TW in 2100
Office of Science, U. S. DOE Basic Research Needs for Solar Energy Utilization. Report from Basic Energy Sciences Workshop on Solar Energy Utilization; 2005.
THE ENERGY SOURCES:• Petroleum• Natural Gas• Hydroelectric• Geothermal
• Wind• Nuclear• Solar
Global Energy: The Solution
In one hour enough energy from sunlight strikes the earth to meet the current energy need of the planet
for an entire year
Electricity Fuels
Solar Cells Biomass, Artificial Systems
1.2 x 105 TW on Earth’s surface36,000 TW on land (world)
2,200 TW on land (US)
Photosynthesis
6CO2 + 6H2O C6H12O6 + 6O2
“Photosynthesis is a process in which light energy is captured and stored by an organism, and then stored energy is used to drive cellular processes.”
Light Reactions
H2O
O2ATP NADPH, H+
ADPNADP+
Pi
CO2
Sugar
Calvin Cycle
Blankenship, Molecular Mechanics of Photosynthesis: 2002
Light Reactions
Chlorophylls
Reaction Center
Electron Transport Chain
Energy transfer
Electron transfer
Catalysis
Light harvesting
In a perfect world, photosynthesis would be perfect.Otto Warburg
Artificial Photosynthesis
Blankenship, Molecular Mechanics of Photosynthesis: 2002
Natural Photosynthesis is only about
1% efficient overall
Need to develop modified natural and
artificial photosynthetic systems
that are >10% efficient for carbon
neutral formation of
H2, CH4, CH3OH and C2H5OH
Basics Artificial Photosynthetic Steps
Light Harvesting
Energy Transfer
Electron Transfer
Catalysis
Photovoltaics
Basics Artificial Photosynthetic Steps
Light Harvesting
Energy Transfer
Electron Transfer
Catalysis
Water Oxidation Carbon Dioxide Reduction
H2 CH3OH, COFischer-TropschProcess
Photovoltaics
Catalysis
2H2O ↔ 2H2 + O2
2H2O ↔ O2 + 4H+ + 4e-
2H+ + 2e- ↔ H2
Water Splitting (Oxygen Evolution)
Proton Reduction (Hydrogen Evolution)
E° = 1.23 V vs NHE
Water Oxidation
Carbon Dioxide Reduction
CO2 + 2H+ + 2e- ↔ CO + H2O
CO2 + 6H+ + 6e- ↔ CH3OH + H2O
E° = -0.53 V vs. NHE
E° = -0.38 V vs. NHE
Current Technological Maturity
Sunlight Solar Cell Water Electrolyzer
Sunlight Fully Integrated System Fuel Output
Hambourger et al., Chem. Soc. Rev. 2009, 38, 25-35.
State-of-the-Art
Future Direction
(expensive and/or hazardous, < 13% efficient )
Fuel OutputCurrent
Players & Research: Centers
August 2008NFS Funds “Powering the
Plant: A Chemical Center for Innovation”
(13 Universities, BP Solar, Brookhaven, Southern California Edison)
August 2009DOE Funds 46 Frontier Energy
Research Centers (EFRCs)(27 EFRCs with some solar research, 7 largely
focused on solar research)
July 2010DOE establishes the Joint Center for
Artificial Photosynthesis (JCAP)(California Institute of Technology & Lawrence Berkeley
National Laboratory)
Including the Argonne-Northwestern Solar Energy Research (ANSER) Center
Players & Research: PIs
MaterialsPaul Alivisatos (LBL)
Harry Atwater (CalTech)Thomas Mallouk (Penn State)Anna Moore (Arizona State)Tom Moore (Arizona State)Klaus Müllen (Max Planck)Michael Pellin (Argonne)
John Rogers (Illinois)Frank Würthner (Würzburg)
Peidong Yang (Berkeley)Luping Yu (Univ. of Chicago)
Theory/ModelingJames Muckerman (BNL)Jens Norskov (Stanford)
Mark Ratner (Northwestern)Gregory Voth (Univ. of Chicago)
ArchitecturesJon Birge (Univ. of Chicago)
Phil Krein (Illinois)Eric McFarland (UCSB)
** Not a comprehensive list
Players & Research: PIs
PhotovoltaicsJames Durrant (Imperial)
Stephen Forrest (Michigan)Michael Grätzel (Lausanne)Joseph Hupp (Northwestern)Ghassen Jabbour (KAUST)Rene Janssen (Eindhoven)
Michio Kondo (AIST)Tobin Marks (Northwestern)Michael McGehee (Stanford)
Art Nozik (NREL)Ralph Nuzzo (Illinois)
Garry Rumbles (NREL)John Turner (NREL)Peng Wang (CIAC)
Photodriven CatalysisHarry Gray (CalTech)
Devens Gust (Arizona State)Leif Hammarström (Uppsala)
Nate Lewis (CalTech)Michael Wasielewski (Northwestern)
PhotosynthesisJames Barber (Imperial)
Stenbjorn Styring (Uppsala)
PhotocatalysisBruce Brunschwig (Yale)Kazunari Domen (Tokyo)
Tom Meyer (UNC)Bruce Parkinson (Wyoming)
** Not a comprehensive list
Players & Research: PIs
Water SplittingAndrew Bocarsly (Princeton)
Gray Brudvig (Yale)G. Charles Dismukes (Rutgers)
Craig Hill (Emory)Daniel Nocera (MIT)
Proton ReductionFraser Armstrong (Oxford)
Mark Fontecave (CEA Grenoble)Vincent Artero (CEA Grenoble)
Marcetta Darensbourg (Texas A&M)
Catalysis (general)Lin Chen (ANL/Northwestern)
Allen Bard (Texas)Jeffrey Long (Berkeley)
Wolfgang Lubitz (Max Planck)David Milstein (Weizmann)Jonas Peters (Cal Tech)Notker Roesch (Munich)T. Don Tilley (Berkeley)
Junko Yano (LBL)
CO2 ReductionDaniel DuBois (PNNL)
Etsuko Fujita (BNL)Clifford Kubiak (UCSD)
Peter Stair (Northwestern)
** Not a comprehensive list
Challenges
- Development of high performance, cost-effective light absorbing materials for use in photovoltaics
- Discovery and development of cost-effective catalysts that have long-term stability and can be linked to photovoltaic technologies
- Design and discovery of interconnected membrane networks that provide a physical support network for the overall process
- Design of interfacial materials that link light absorbers to catalysts to allow for efficient control of the integrated system
- Development and design of architectures that allow for scaling-up from the nanoscale to the macroscale
Key Findings: #1
High Throughput Approach to Catalyst Screening
Woodhouse, M.; Parkinson, B. A., Chem. Soc. Rev. 2009, 38, 197-210. Jaramillo, T. F. et al, J. Combinatorial Chem. 2004, 7, 264-271.
Objective: Find stable, robust, earth-abundant photoanodes for water oxidation
Method: Catalyst screening with an automated electrochemical deposition of metal oxides
Results: A critical innovation for rapid identification of water oxidation catalysts
PIs: Bruce Parkinson (Wyoming),Eric McFarland (UCSB), & Tom Jaramillo (Cal Tech)
Key Findings: #2
Self-healing, Self-assembling Oxygen-Evolving Catalyst
Kanan, M. W.; Surendranath, Y.; Nocera, D. G., Chem. Soc. Rev. 2009, 38, 109-114.
Objective: Find stable, robust, earth-abundant catalyst for water oxidation
Method: Synthesize catalysts and study their catalytic properties using electrochemistry
Results: Cobalt-phosphate catalyst self-assembles and oxidizes water over a wide pH range with self-healing properties
PI: Daniel Nocera (MIT)
Key Findings: #3
Molecular Level Understanding of Accumulative Electron Transfer
Magnuson, A. et al.., Acc. Chem. Res. 2009, 42, 1899-1909.
Objective: Understand the basic photophysics of photodriven molecular catalysis
Method: Synthesized PSII molecular mimics and used ultrafast laser spectroscopy to quantify photophysics
Results: Observed multi-step electron transfer to PSII mimic, demonstrates inherent complexity of photodriven catalysis
PI: Leif Hammarström (Uppsala)
Key Finding: #4
NN
O
O
O
O
N
C8H17
C8H17
NNH33C1
6
H33C16 O
O N
C8H17
C8H17
N NC16H33
C16H33
Self-Assembly of Photoactive Charge Conduits for Integrated Solar Fuels Systems
Wasielewski, M. R., Acc. Chem. Res. 2009, 42, 1910-1921.
Objective: Generate functional self-assembling molecular conduits
Method: Synthesize molecular systems and use ultrafast laser spectroscopy to determine photophysics
Results: Self-assembling donor-acceptor systems show efficient light harvesting and electron transfer
PI: Michael Wasielewski (Northwestern)
Key Findings: #5
DuBois, M. R.; DuBois, D. L., Chem. Soc. Rev. 2009, 38, 62-72.
Pendant Base Incorporation in Molecular Catalysts for Hydrogen Production
Objective: Find stable, robust, earth-abundant catalyst for hydrogen evolution
Method: Mechanistic studies of nickel/cobalt catalysts
Results: Pendant base incorporation facilitates proton/hydride interactions and help tune electronic/steric properties
PI: Daniel DuBois (PNNL)
Key Findings: #6
Singlet Fission for Enhanced Charge Generation
Smith, M. B.; Michl, J., Chem. Rev. 2010, 110, 6891-6936.
Objective: Improve overall power conversion efficiencies of organic PVs
Method: Identify molecules that yield higher energy conversion rates
Results: Molecules that undergo singlet fission increase theoretical power efficiencies and a few molecules have been shown to undergo this process
PI: Josef Michl (Colorado-Boulder)
Future Outlook
Promising emergent technology to impact future transportation fuels
The technology is not currently economically viable.
R&D efforts are extensive, which presents a positive future outlook for a large solar fuels impact.
Technology output qualitative timeline:1. Hydrogen generation and conversion to hydrocarbon fuels as the initial first technology established through wired PV-Electrolyzer device.
2. CO2 reduction poses a more difficult scientific challenge, but offers the potential for the largest future impact (to provide a fuel source & mitigate climate change).
3. Fully integrated artificial photosynthetic system is ideal, but will take significant chemical consideration & engineering effort.