Artificial photosynthesis for solar fuels Stenbjörn Styring Uppsala university

Swedish Consortium for Artificial Photosynthesis Sw. Energy agency, Knut and Alice Wallenberg Foundation; EU; VR

The global concept Nuclear Biomass Hydro others..... TW 40 80% Fossil 2011; ca 17 TW years Global energy use

Energy supply 2008, Sweden: % of total Local vs. global concept Fossil Nuclear Biomass Hydro

Energy supply 2008, Sweden: % of total Local vs. global concept Fossil Nuclear Energy supply 2008; Germany % of total Fossil Biomass Hydro

TW The global concept : 17 TW 80% Fossil

TW The global concept Note! This comes from people that don´t use energy today. They can not solve this by saving energy!!! Note! This comes from people that don´t use energy today. They can not solve this by saving energy!!! : 17 TW 80% Fossil

Renewable technologies (Sims et al, IPCC 2007) Electricity Technologically mature with marketshydroelectric; geothermal; in at least some countrieswoody biomass; onshore wind landfill gas; bioethanol; silicon solar cells..... Technologically mature with small, newsolid waste energy in towns; markets in few countriesbiodiesel; offshore wind; heat concentrating solar dishes... Under technological developmentthin film PV; tidal change; wave demonstration plants, upcomingbiomass gasification; pyro- lysis; bioethanol from ligno- cellulose; thermal towers Many give electricity

TW Everything is not electricity 2011; ca 17 TW years Fossil 80% Total production

TW % Electricity 17% Fossil Everything is not electricity Total production Final consumtion

TW % Electricity 17% The rest, 83% is used as fuel for many things Fossil Everything is not electricity Total production Final consumtion

1.Electricity is an energy carrier. It is used to carry a minor part of the energy in the world. Critical insights

1.Electricity is an energy carrier. It is used to carry a minor part of the energy in the world. 2. Biomass is limited on a global scale. Although important in many regions, there is not enough to replace fossile fuels. 1.Electricity is an energy carrier. It is used to carry a minor part of the energy in the world. 2. Biomass is limited on a global scale. Although important in many regions, there is not enough to replace fossile fuels. Critical insights

Renewable technologies Biomass derived Technologically mature with marketshydroelectric; geothermal; in at least some countrieswoody biomass; onshore wind landfill gas; bioethanol; silicon solar cells..... Technologically mature with small, newsolid waste energy in towns; markets in few countriesbiodiesel; offshore wind; heat concentrating solar dishes... Under technological developmentthin film PV; tidal change; wave demonstration plants, upcomingbiomass gasification; pyro- lysis; bioethanol from ligno- cellulose; thermal towers Research stage Many give electricity. All fuel technologies are based on biomass

1.Electricity is an energy carrier. It is used to carry a minor part of the energy in the world. 2. Biomass is limited on a global scale. Although important in many regions, there is not enough to replace fossile fuels. 3. Need for fuels from other renewable resources than biomass 1.Electricity is an energy carrier. It is used to carry a minor part of the energy in the world. 2. Biomass is limited on a global scale. Although important in many regions, there is not enough to replace fossile fuels. 3. Need for fuels from other renewable resources than biomass Critical insights

!! Converted solar energy; Oil,biomass…. Electricity Solar cells ! ? Heat; Low temp High temp Solar Energy, Options 12

The energy system – local versus global aspects; the place for solar energy; need for fuel Various concepts for solar fuels Our science in the Swedish Consortium for Artificial Photosynthesis

Solar fuel; hydrogen or carbon based Solar energy and water Sustainable methods to make solar fuels/hydrogen

Solar fuel; hydrogen or carbon based Indirect Direct methods Solar energy and water Sustainable methods to make solar fuels/hydrogen

Photovoltaics Solar fuel; hydrogen or carbon based Indirect Electrolysis→H 2 Solar energy and water Sustainable methods to make solar fuels/hydrogen

Photovoltaics Solar fuel; hydrogen or carbon based Indirect Electrolysis→H 2 Leads to discussions about the hydrogen society Solar energy and water Sustainable methods to make solar fuels/hydrogen

Photovoltaics Solar fuel; hydrogen or carbon based Indirect Electrolysis→H 2 C-based fuel From H 2 and CO 2 Solar energy and water Sustainable methods to make solar fuels/hydrogen

Solar fuel; hydrogen or carbon based Biomass Conversion Pyrol.,ferm., chop wood etc Indirect Solar energy and water Sustainable methods to make solar fuels/hydrogen

Photosynthesis Solar fuel; hydrogen or carbon based Indirect Biomass Conversion Solar energy and water Sustainable methods to make solar fuels/hydrogen

Photovoltaics Photosynthesis Solar fuel; hydrogen or carbon based Indirect Electrolysis→H 2 Biomass Conversion Pyrolysis, ferment., etc C-based fuel From H 2 and CO 2 Solar energy and water Sustainable methods to make solar fuels/hydrogen

Solar fuel; hydrogen or carbon based Electricity Electrolysis Indirect Solar cells in Sala/Heby Two systems -solar cells and electrolyser Solar energy and water Sustainable methods to make solar fuels/hydrogen

Solar fuel; hydrogen or carbon based Indirect Biomass, Trees; Waste; Grasses Biomass, Trees; Waste; Grasses Conversion Several systems must be integrated Solar energy and water Sustainable methods to make solar fuels/hydrogen

Solar fuel; hydrogen or carbon based Electricity Electrolysis Indirect Solar cells in Sala/Heby Biomass, Waste; Trees; Grasses Biomass, Waste; Trees; Grasses Conversion General - Extra systems cost Losses in extra step(s) Solar energy and water Sustainable methods to make solar fuels/hydrogen

Solar fuel; hydrogen or carbon based Direct methods Solar energy and water

Thermochemical cycles (CSP for H 2 ) Solar fuel; hydrogen or carbon based Direct methods Solar energy and water

Artificial Photosynthesis in materials and nanosystems Artificial Photosynthesis in molecular systems Solar fuel; hydrogen or carbon based Direct methods Thermochemical cycles (CSP for H 2 ) Solar energy and water

e-e- e-e- e-e- e-e- D D 2 H 2 O O H + A A 2 H 2 4 H + H + e-e- e-e- P P Joining in cells P

Artificial Photosynthesis in materials and nanosystems Artificial Photosynthesis in molecular systems Solar fuel; hydrogen or carbon based Direct methods Thermochemical cycles (CSP for H 2 ) System costs might become lower in a direct process Solar energy

Solar fuel; hydrogen or carbon based Semi-direct Solar energy Photosynthesis (compartmentalized) Light reactions NADPH & ATP Dark reactions H 2, alcohols etc Photobiological processes – not harvesting the organism Excreted

H 2 forming heterocyst Vegetative cells Green algae – Chlamydomonas Can make hydrogen under special conditions Cyanobacterium – Nostoc Photobiological hydrogen and fuel production using living organisms.

Solar fuel; hydrogen or carbon based Something in between Mixing biological and non-biological parts Solar energy PSIIPSII PSIPSI H 2 ses Ru Pt Hybrides Enzyme & metal catalysts TiO2 etc

Artificial Photosynthesis in materials and nanosystems Thermochemical cycles (CSP for H 2 ) Photovoltaics Artificial Photosynthesis in molecular systems Photosynthesis Solar fuel; hydrogen or carbon based Indirect Direct methods Semi-direct Solar energy and water Light reactions NADPH & ATP Dark reactions H 2, alcohols etc Electrolysis→H 2 Biomass Conversion Pyrolysis, ferment., etc C-based fuel From H 2 and CO 2 Photosynthesis (compartmentalized)

The energy system – local versus global aspects; the place for solar energy; need for fuel Various concepts for solar fuels A little on our science in the Swedish Consortium for Artificial Photosynthesis

H2H2 PP We follow two branches to Solar hydrogen, common link biochemistry, biophysics H2OH2O

H2H2 PP Photobiological hydrogen production in photosynthetic microorganisms H2OH2O Design of organisms Synthetic biology, genomics, metabolomics

H2OH2O H2H2 PP Design and synthesis Spectroscopy Artificial photosynthesis, synthetic light driven catalytic chemistry Mn Ru Fe CoCo

Artificial photosynthesis: Target – fuel from solar energy and water! Visionary – but how?

Artificial photosynthesis - manmade: Visionary – but how? Idea for a short cut: Mimic (copy) principles in natural enzymes Method Biomimetic chemistry

Mn PP O2O2 O2O2 O2O2 O2O2 ? Secret of life Element: Mn Atomic weight: 55 Mn Four manganese atoms are the secret behind the splitting of water O2O2 O2O2 O2O2 Water Photosystem II – the wunderkind in nature!

Tyr Z 161 His 190 Glu 189 Asp 170 Gln 165 Ca Water oxidation - the main players OHOH Mn

N N N N N N D A S H O 2 2 O 2 + e - e - 4H + + H 2 2 Link light Ruthenium instead of chlorophyll Supramolecular chemistry chemical LEGO Ru

N N N N N N D A S H O 2 2 O 2 + e - e - 4H + + H 2 2 Link light Supramolecular chemistry chemical LEGO Mn Link Ru Manganese as in Photosystem II

Mn Mn 2 (II/II) BPMP has been connected to Ru and electron acceptors N N N N N N N N N N C 8 H 17 O O O O C 8 H 17 O O O O ONN NN N N NHO EtO 2 C OOOO 3+ Ru Mn NDI acceptor Mw 2800

We seek catalysts based on abundant metals, Mn-based systems have potential - The Mn 4 cluster works in Photosystem II - It is the most efficient and stable part of PSII electron transfer Co-based systems have potential - We seek molecular systems - We seek light driven systems

Cobalt as a water oxidation catalyst Kanan and Nocera, Science 2008, 321, 5892, Yin, Tan, Besson, Geletii, Musaev, Kuznetsov, Luo, Hardcastle and Hill, Science 2010, 328,

1 O 2 /Co ON OFF ON 100 % light 50 % light Co(III) oxide Photo-driven O 2 evolution with a new Co-nanoparticle

e- Co 2 H 2 O O H + Ru Development of a Co-ligand system for use in the split cell. 1. Link the Ru-sensitizer with ligand H 4 M2P (M2P for short) methyldiphosphonic acid

e- Co 2 H 2 O O H + Ru 1. Synthesized and characterized. Ru(M2P) Development of a Co-ligand system for use in the split cell. 1. Link the Ru-sensitizer with ligand H 4 M2P (M2P for short) methyldiphosphonic acid

+ P i buffer + persulfate + light Isolated Ru(M2P)Co 65 µg Ru(M2P)Co (ca 40 µM Ru) 6 mM S 2 O mM Pi (pH 8.4) Development of a Co-ligand system for use in the split cell. Ca 1 turnover Photocatalytic oxygen evolution!

e- Co 2 H 2 O O H + Ru 1.Synthesized and characterized. 2.Yes, it binds Co and the system is photo-catalytic! Ru(M2P) Development of a Co-ligand system for use in the split cell. 1.Link the Ru-sensitizer with ligand 2. Can it bind Co and is it active? H 4 M2P (M2P for short) methyldiphosphonic acid

N N N N N N D A S H O 2 2 O 2 + e - e - 4H + + H 2 2 Link light Supramolecular chemistry chemical LEGO Mn Link Ru Co(III) oxide Cobolt

N N N N N N D A S H O 2 2 O 2 + e - e - 4H + + H 2 2 Link light Supramolecular chemistry chemical LEGO Mn Link Ru Manganese like Photosystem II Co(III) oxide Cobolt

Hydrogenases: Enzymes that can make and handle hydrogen Fe

Many complexes making hydrogen!! seconds turnovers Hydrogen formation. Electrochemistry under very acidic conditions Background Our complex

Aromatic dithiolate ligands Tuning for catalysis at milder potentials Diiron complexes with aromatic dithiolate ligands quinoxaline carborane

1 2 3 e-e- e-e- 4 H+H+ 5 ½ H 2 Ascorbic acid Ru(bpy) 3 2+ Fe 2 (μ-Cl 2 -bdt)(CO) 6 Bimolecular approach Setup: 150 W halogen lamp as light source 455 nm long-pass filter + infrared filter light power at sample (=after filtering) ~ 1 W sample degassed and under Ar atmosphere solvent: H 2 O:Acetonitrile 1:1 or H 2 O:Dimethylformamide 1:1 typical concentrations: 1.Ascorbic acid: 0.1M 2.Sensitizer: 140 μ M 3.Catalyst: 14 μM typical sample volume: 2.6 ml H 2 detected by gas chromatography Components: Ascorbic acid as proton and electron donor Ruthenium(II)tris- bipyridine as photosensitizer Diiron-( μ- Dichlorobenzene- dithiolate)hexacarbonyl catalyst

An interesting development – complexes with only one Fe can also make hydrogen. S S Fe II Ph 2 P PPh 2 CO N O O Hydrogen at low overpotential

N N N N N N D A S H O 2 2 O 2 + e - e - 4H + + H 2 2 Link light Supramolecular chemistry chemical LEGO Mn Link Ru Co(III) oxide Cobolt Fe

We have water oxididation catalystCo-nanoparticle We have many hydrogen forming catalystsFe-complexes We can drive them with light! Can we combine them?

O 2 + 4H + e- 2 H 2 O 4H + e- 2 H 2 e- TiO 2 NiO A ”Split-cell” for complete water oxidation/fuel formation with catalysts of earth abundant elements from our laboratory A ”Split-cell” for complete water oxidation/fuel formation with catalysts of earth abundant elements from our laboratory

Artificial Systems Organisms in Bioreactors H 2 by photosynthesis Water as substrate Soon -will work -explored by many

Artificial Systems Bioreactors H 2 by photosynthesis Water as substrate Soon -will work -explored by many Long term - big potential - more unproven