Artificial photosynthesis for
solar fuels
Stenbjörn Styring
Uppsala university
Swedish Consortium for
Artificial Photosynthesis
1994-
Sw. Energy agency, Knut and Alice Wallenberg Foundation; EU; VR
The global concept
Global energy use
Nuclear Biomass
Hydro
others.....
2011; ca 17 TW years
Fossil
80%
0
10
TW
20
30
40
Local vs. global concept
Energy supply 2008, Sweden:
Hydro Biomass
Fossil
33
Nuclear
32
12
23
% of total
Local vs. global concept
Energy supply 2008, Sweden:
Hydro Biomass
Nuclear
Fossil
33
32
12
23
% of total
Energy supply 2008; Germany
Fossil
82
11 7
% of total
The global concept
Fossil
2050
Fossil
2011: 17 TW
80%
0
20
10
TW
30
40
The global concept
Note! This comes from people that don´t use energy
today. They can not solve this by saving energy!!!
Fossil
2050
Fossil
2011: 17 TW
80%
0
20
10
TW
30
40
Renewable technologies (Sims et al, IPCC 2007) Electricity
Technologically mature with markets
in at least some countries
hydroelectric; geothermal;
woody biomass; onshore wind
landfill gas; bioethanol; silicon
solar cells.....
Technologically mature with small, new
markets in few countries
solid waste energy in towns;
biodiesel; offshore wind; heat
concentrating solar dishes...
Under technological development
demonstration plants, upcoming
thin film PV; tidal change; wave
biomass gasification; pyrolysis; bioethanol from lignocellulose; thermal towers.......
Many give electricity
Everything is not electricity
Total production
2011; ca 17 TW years
Fossil
80%
10
TW
20
Everything is not electricity
Final consumtion
Electricity 17%
Total production
Fossil
80%
10
TW
20
Everything is not electricity
Final consumtion
Electricity 17%
The rest, 83% is used as
fuel for many things
Total production
Fossil
80%
10
TW
20
Critical insights
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.
Renewable technologies
Biomass derived
Technologically mature with markets
in at least some countries
hydroelectric; geothermal;
woody biomass; onshore wind
landfill gas; bioethanol; silicon
solar cells.....
Technologically mature with small, new
markets in few countries
solid waste energy in towns;
biodiesel; offshore wind; heat
concentrating solar dishes...
Under technological development
demonstration plants, upcoming
thin film PV; tidal change; wave
biomass gasification; pyrolysis; bioethanol from lignocellulose; thermal towers.......
Manystage
give
Research
electricity.
All fuel technologies are
based on biomass
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.
3. Need for fuels from other renewable resources
than biomass
Solar Energy, Options
Converted solar
energy;
Oil,biomass….
Solar fuel
for storage
!!
Heat;
Low temp
High temp
!!
!?
Solar cells
Electricity
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 energy and water
Direct methods
Indirect
Solar fuel; hydrogen or carbon based
Sustainable methods to make solar fuels/hydrogen
Indirect
Photovoltaics
Electrolysis→H2
Solar fuel; hydrogen or carbon based
Solar energy and water
Sustainable methods to make solar fuels/hydrogen
Indirect
Photovoltaics
Leads to discussions about
the hydrogen society
Electrolysis→H2
Solar fuel; hydrogen or carbon based
Solar energy and water
Sustainable methods to make solar fuels/hydrogen
Indirect
Photovoltaics
Electrolysis→H2
C-based fuel
From H2 and CO2
Solar fuel; hydrogen or carbon based
Solar energy and water
Sustainable methods to make solar fuels/hydrogen
Indirect
Biomass
Conversion
Pyrol.,ferm., chop wood etc
Solar fuel; hydrogen or carbon based
Solar energy and water
Sustainable methods to make solar fuels/hydrogen
Indirect
Photosynthesis
Biomass
Conversion
Solar fuel; hydrogen or carbon based
Solar energy and water
Sustainable methods to make solar fuels/hydrogen
Indirect
Photovoltaics
Electrolysis→H2
Photosynthesis
Biomass
C-based fuel
From H2 and CO2
Conversion
Pyrolysis, ferment., etc
Solar fuel; hydrogen or carbon based
Solar energy and water
Sustainable methods to make solar fuels/hydrogen
Sustainable methods to make solar fuels/hydrogen
Electricity
Electrolysis
Solar cells in Sala/Heby
Two systems -solar cells and
electrolyser
Solar fuel; hydrogen or carbon based
Solar energy and water
Indirect
Sustainable methods to make solar fuels/hydrogen
Biomass,
Trees;
Waste;
Grasses
Conversion
Several systems must
be integrated
Solar fuel; hydrogen or carbon based
Solar energy and water
Indirect
Solar energy and water
Indirect
General -
Extra systems cost
Losses in extra step(s)
Electricity
Electrolysis
Solar cells in Sala/Heby
Biomass,
Waste;
Trees;
Grasses
Conversion
Solar fuel; hydrogen or carbon based
Sustainable methods to make solar fuels/hydrogen
Solar fuel; hydrogen or carbon based
Solar energy and water
Direct methods
Thermochemical cycles (CSP for H2)
Solar fuel; hydrogen or carbon based
Solar energy and water
Direct methods
Direct methods
Solar energy and water
Artificial Photosynthesis in molecular systems
Artificial Photosynthesis in materials and nanosystems
Solar fuel; hydrogen or carbon based
Thermochemical cycles (CSP for H2)
Joining in cells
H+ H+
2 H2O
O2 + 4
H+
D
e-
P
P
e-
e-
e-
A
4 H+
2 H2
Direct methods
Artificial Photosynthesis in molecular systems
Solar energy
Artificial Photosynthesis in materials and nanosystems
System costs might become lower
in a direct process
Solar fuel; hydrogen or carbon based
Thermochemical cycles (CSP for H2)
Semi-direct
Light reactions
Photosynthesis
Dark reactions
NADPH & ATP
(compartmentalized)
H2, alcohols etc
Photobiological processes – not harvesting the organism
Solar fuel; hydrogen or carbon based
Solar energy
Excreted
Photobiological hydrogen and fuel
production using living organisms.
Vegetative cells
H2 forming heterocyst
Cyanobacterium – Nostoc
Green algae –
Chlamydomonas
Can make hydrogen
under special conditions
Mixing biological and non-biological parts
Solar energy
H2ses Ru
TiO2
etc
PSII
Pt PSI
Hybrides
Enzyme & metal catalysts
Solar fuel; hydrogen or carbon based
Something in between
Direct methods
Solar energy and water
Artificial Photosynthesis in materials and nanosystems
Thermochemical cycles (CSP for H2)
Semi-direct
Light reactions
Photosynthesis
Dark reactions
NADPH & ATP
(compartmentalized)
H2, alcohols etc
Indirect
Photovoltaics
Electrolysis→H2
Photosynthesis
Biomass
C-based fuel
From H2 and CO2
Conversion
Pyrolysis, ferment., etc
Solar fuel; hydrogen or carbon based
Artificial Photosynthesis in molecular systems
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
We follow two branches to Solar hydrogen,
common link biochemistry, biophysics
H2O
P
H2
Photobiological hydrogen production in photosynthetic
microorganisms
H2O
Design of organisms
Synthetic biology, genomics,
metabolomics
P
H2
Artificial photosynthesis, synthetic
light driven catalytic chemistry
H 2O
Fe
Ru
Fe
Mn
C
o
Mn
P
Design and synthesis
Spectroscopy
H2
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
Photosystem II – the wunderkind in nature!
O2
P
O2
O2
O2
O2
O2
O2
? Secret of life
Element: Mn
Atomic weight: 55
Mn
Mn
Mn
Mn
Water
Four manganese atoms
are the secret behind
the splitting of water
Water oxidation - the main players
TyrZ 161
His 190
Gln 165
OH
Glu 189
Ca
Asp 170
Mn
Mn
Mn Mn
Supramolecular chemistry
chemical LEGO
2 H 2O
4H
D
O2 +4H
+
S
Link
e-
Link
e-
+
A
2 H2
N
N
N
Ru
N
N
N
Ruthenium instead
of chlorophyll
Supramolecular chemistry
chemical LEGO
2 H 2O
4H
D
O2 +4H
S
Link
+
e-
Link
e-
N
Mn
Link
Mn
Manganese as in
Photosystem II
N
N
Ru
N
N
N
+
A
2 H2
Mn2(II/II) BPMP has been connected to Ru and
electron acceptors
C H
8 17 N
N
N
N
O
O
O
O
O
NDI acceptor O
C8H17
O
O
O
N
N
N
N
Mn
Mn
N
O
O
N
3+
O
O
N
N
N
N
Ru
N
N
N
N
N
Ru
N
O
N
N
NH
EtO2C
Me
NH
EtO2C
N
N
O
N
Mn Mn
N
N O OO O N
N
N
Mn
O
N
Mn
N O O O O N
Me Me
N
Mw 2800
We seek catalysts based on abundant metals,
Mn-based systems have potential
- The Mn4 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, 1072-1075
Yin, Tan, Besson, Geletii, Musaev, Kuznetsov, Luo,
Hardcastle and Hill, Science 2010, 328, 342-345
Photo-driven O2 evolution
with a new Co-nanoparticle
O
O
-
O
P
O
P
-
O
-
O
-
Co(III) oxide
ON
50 % light
OFF
ON
1 O2/Co
100 % light
Development of a Co-ligand system
for use in the split cell.
1. Link the Ru-sensitizer with ligand
2 H2O
O2 + 4
H+
Co
e-
Ru
H4M2P (M2P for short)
methyldiphosphonic acid
Development of a Co-ligand system
for use in the split cell.
1. Link the Ru-sensitizer with ligand
2 H2O
O2 + 4
H+
Co
e-
Ru
H4M2P (M2P for short)
methyldiphosphonic acid
Ru(M2P)
1. Synthesized and characterized.
Development of a Co-ligand system
for use in the split cell.
65 µg Ru(M2P)Co
(ca 40 µM Ru)
6 mM S2O8225 mM Pi (pH 8.4)
Isolated Ru(M2P)Co
Photocatalytic oxygen
evolution!
50
O2 (nmol/ml)
+ Pi buffer
+ persulfate
+ light
40
30
20
Ca 1 turnover
ON
10
0
0
100
200
300
Time (s)
400
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?
2 H2O
O2 + 4
H+
Co
e-
Ru
H4M2P (M2P for short)
methyldiphosphonic acid
Ru(M2P)
1. Synthesized and characterized.
2. Yes, it binds Co and the system
is photo-catalytic!
Supramolecular chemistry
chemical LEGO
2 H 2O
4H
D
O2 +4H
S
Link
+
e-
Link
e-
Cobolt
Co(III)
oxide
N
Mn
Link
Mn
N
N
Ru
N
N
N
+
A
2 H2
Supramolecular chemistry
chemical LEGO
2 H 2O
4H
D
O2 +4H
S
Link
+
e-
Link
e-
Cobolt
Co(III)
oxide
N
Mn
Link
Mn
Manganese like
Photosystem II
N
N
Ru
N
N
N
+
A
2 H2
NC
CO
O
C
Fe
Fe
OC
S
CN
Fe
Fe
S
X
S
Cys
NH
Hydrogenases: Enzymes
that can make and handle
hydrogen
Many complexes making hydrogen!!
Hydrogen formation.
Electrochemistry under very
acidic conditions
Br
-12
20
N
turnovers
25
Our complex
15
-8
S S
10
Fe
OC
Fe
CO
-4
5
OC
CO
CO
CO
Background
0
0
200
400
seconds
600
Diiron complexes with aromatic dithiolate ligands
quinoxaline
carborane
Aromatic dithiolate ligands
Tuning for catalysis at milder potentials
Bimolecular approach
1
½ H2
e-
5
2
e3
Ascorbic acid
Fe2(μ-Cl2-bdt)(CO)6
Ru(bpy)32+
4
H+
An interesting development – complexes with only
one Fe can also make hydrogen.
S S
FeII CO
Ph2P
PPh2
N
O
O
Hydrogen at low overpotential
Supramolecular chemistry
chemical LEGO
2 H 2O
4H
D
O2 +4H
S
Link
+
e-
Link
e-
+
A
2 H2
Cobolt
Co(III)
oxide
N
Mn
Link
Mn
N
N
Ru
N
N
N
Fe
Fe
Fe
We have water oxididation catalyst
Co-nanoparticle
We have many hydrogen forming catalysts
We can drive them with light!
Can we combine them?
Fe-complexes
A ”Split-cell” for complete water oxidation/fuel formation
with catalysts of earth abundant elements from our laboratory
e-
e-
e-
a)
e-
2-
O 3P
N
Ru
N
O 3P
TiO2
N
N
c)
H
O2 + 4HN+
[4F e-4S ]
N
N
2-
b)
Co(III) oxideC ys
S S
Fep
OC
NC
2 H2O
CN
CO
M e3P
O
I
Fe
OC
PM e3
CO
S
OC
Ph
S
Fe
II
N
Co
N
eO
II
N
N
F2
NCMe
X2
CO2H
Ar =
Ph
tBu
OO
O
1
B OAr
PR2 PR2
X1
2 H2
Ph
O
OAr
ON
tBu
SH
S
Fed
C
O
e-
4H+
S
R 2N
F2
B
O
OAr
X3
O
OO
Oct N
NN
O
OO
O
NR
2
OAr
NiO
CO H
2
H2 by photosynthesis
Water as substrate
Organisms
in Bioreactors
Soon
-will work
-explored by many
Artificial
Systems
H2 by photosynthesis
Water as substrate
Bioreactors
Artificial
Systems
Long term
Soon
- big potential
-will work
-explored by many - more unproven