Direct homogeneous catalytic carbon
dioxide hydrogenation to formic acid:
The reversible formic acid – carbon
dioxide/hydrogen cycle
Andrew Dalebrook
EPFL Lausanne
2015
A. Dalebrook
1) For transport/mobile applications our energy
infrastructure is based on the fossil fuels (petrol,
natural gas, coal)
- The extensive use of the fossil fuels causes
environmental problems:
CO2 emission, global warming, climate change
From US Energy Information Administration
►► 2) No alternative resources, similar to the fossil fuels, are on the Earth
3
2015
A. Dalebrook
1L ≈ 0.08g
Problem :
3) No ideal hydrogen storage and delivery
system found yet for mobile, portable and
small applications.
7
2015
A. Dalebrook
H2
Hydrogen storage -­‐ delivery Classical/ widely
used storage
H2 pressure
Temperature
Volumetric
hydrogen density
hydrogen gas
200 bar
25 °C
16 g / l
hydrogen gas
350 bar
25 °C
28 g / l
liquid H2
1 bar (700 bar)
- 253 °C
70 g / l*
formic acid
up to 600 bar
25 °C
53 g / l
Nettle
- 253 °C
Ant
Hydrogen storage: beyond conventional methods, A. Dalebrook, W. Gan, M. Grasemann, S.Moret, G.Laurenczy, Chem. Comm., 2013, 49, 8735-8751.
Formic acid as hydrogen source – recent developments and future trends, M. Grasemann, G. Laurenczy, Energy & Environmental Science, 2012, 5, 8171−8181.
8
2015
A. Dalebrook
Formic acid — CO2 system homogeneous catalytic system
ü  efficient, simple
ü  generate very pure H2 (and CO2)
ü  at any wanted pressure up to 110 MPa
ü  constant high pressure H2 delivery
ü in water
catalyst
HCOOH
►► it has a flash point – ignition
temperature of + 69 °C
►► the 85 % formic acid is not
inflammable
►► the diluted formic acid is a
food additive - E236 (US Food
and Drug Administration)
►► only gaseous products
Formic acid production: - ants
-  industry: catalytic CO hydration
-  CO2 hydrogenation - “CO2 utilisation for H2 storage”
delivery
Stand – alone unit for energy storage, no need: electricity/gas/oil network
9
H2 + CO2
Advantages of HCOOH:
C. Fellay, P. J. Dyson, G. Laurenczy, Angew. Chem. Int. Ed., 2008, 47, 3966.
Laurenczy et.al., International Patent, 2006, 2013
from renewable sources
→
2015
A. Dalebrook
Kine9c and mechanis9c studies: hydrogen produc9on Reaction optimisation
Experimental
-  Reactions are performed in medium pressure sapphire
NMR tubes (up to 120 bar), and in autoclaves (batch and
continuous mode, up to 2000 bar).
- 13 C enriched H 13 COOH, H 13 COONa NaH 13 CO 3 ,
Na213CO3, 13CO2 were used for the NMR samples.
- The reaction mechanism was analyzed by variable
pressure and temperature multinuclear (1H, 13C, 31P and
2H) NMR.
12
2015
A. Dalebrook
2. CO2 hydrogena9on
1. Hydrogen/energy supply CO2 + H2 → HCOOH
HCOOH → H2 + CO2
(from renewable
sources)
11
2015
(delivery)
A. Dalebrook
1. Ru(II) catalysts Pre-catalysts
ligands:
ruthenium:
[Ru(H2O)6]2+
[Ru(H2O)6]3+
RuCl3.2H2O
30
2015
A. Dalebrook
1. Ru(II) catalysts 0.022 M Ru(II)
0.056 M Ru(II)
W. Gan, C. Fellay, P. J. Dyson, G. Laurenczy; J. Coord. Chem., 2010, 63, 2685.
31
2015
A. Dalebrook
1. Ru(II) catalysts 100
ruthenium:
a)  [Ru(H2O)6]2+
- substitution reaction
on Ru(II) hexaaqua
- kex= 0.018 s-1
b) RuCl3.2H2O
- kex= 3.5x10-6 s-1
- redox reaction of Ru(III)
conversion / %
80
60
Kinetic traces for RuCl3·2H2O with TPPTS, 1st
(■), 3rd (●), 5th (▲) cycle, compared to 1st
(▲) and 3rd (■) cycle of [Ru(H2O)6][tos]2; 22.5
mM Ru, 2 eqv. TPPTS, 4 M HCOOH/
HCOONa, 2.5 ml H2O/D2O (1:1), addition of
0.38 ml HCOOH for recycling.
40
20
0
0
1
2
3
4
5
time / h
C. Fellay, P. J. Dyson, G. Laurenczy, Angew. Chem. Int. Ed., 2008, 47, 3966.
A. Thevenon, E. Frost-Pennington, W. Gan, A. Dalebrook, G. Laurenczy, ChemCatChem, 2014, 6, 3146.
2015
A. Dalebrook
6
7
1. Ru(II) catalysts Reaction optimisation (Ru – mTPPTS system)
CO poisoning
Temperature
100
100
80
60
■ 120°C
■ 100°C
■ 90°C
■ 80°C
■ 70°C
■ 25°C
40
20
conversion / %
conversion / %
80
1
2
60
80
100
120
16th recycling
17th recycling (+CO)
18th recycling
20th recycling
22nd recycling
23rd recycling
40
20
0
0
60
0
140
0
t/h
1
2
3
4
5
t/h
Kinetic traces of formic acid decomposition at different temperatures:
activated catalytic solution (22 mM [Ru]2+, 2 eqv. TPPTS). 4 M HCOOH/
HCOONa (9:1)
C. Fellay, N.Yan, P. J. Dyson, G. Laurenczy, Chem. Eur. J., 2009, 15, 3752.
32
2015
A. Dalebrook
1. Hydrogen/energy supply (2) 31P 55.9,
H13COOH
13C
178.6 (JHC = 207)
Reaction mechanism
1H
1H{13C}
P= mTPPTS3-15.6
(3)
1H
13C{1H}
13C
204.0
203.4
203.0
-15.8 (JHP = 20, JHC = 9)
C. Fellay, N.Yan, P. J. Dyson, G. Laurenczy, Chem. Eur. J., 2009, 15, 3752.
A. Thevenon, E. Frost-Pennington, W. Gan, A. Dalebrook, G. Laurenczy, ChemCatChem, 2014, 6, 3146.
36
-15.8
1H{31P}
(6) 31P 52.2, 1H -9.6 (JHP = 37)
(3) 31P 45.7
13C 203.4 (J
CP = 16, JHC = 9),
-15.6
-15.8
2015
A. Dalebrook
-15.68
-15.76
(3)
1. Ru(II) catalysts Structure of the oligocationic, ammoniomethylsubstituted triarylphosphine ligands
W. Gan, D.J.M. Snelders, P.J. Dyson, G. Laurenczy, ChemCatChem, 2013, 5, 1126.
37
2015
A. Dalebrook
1. Ru(II) catalysts 1600
1430
1400
1140
1200
1080
1130
TOF (h-1)
1000
800
740
600
600
480
400
200
130
110
80
0
1
2
3a
3b
4
5
6
mTPPTS mTPPDS PTA
Comparison of the activities on Ru-catalyzed HCOOH decomposition in the presence of cationic (1 – 6, in green), anionic
(mTPPTS and mTPPDS, in blue) and neutral (PTA, in red) phosphine ligands. Catalysts formed in situ with 28 mM RuCl3·xH2O
(56 mM for PTA system), 10 M HCOOH/HCOONa (9:1), 2 eqv. phosphine ligands to Ru, 90°C; TOF was calculated on 5th cycle
of each catalyst.
W. Gan, D.J.M. Snelders, P.J. Dyson, G. Laurenczy, ChemCatChem, 2013, 5, 1126.
38
2015
A. Dalebrook
1. Ru(II) catalysts Heterogeneous Silica-Supported Ruthenium Phosphine Catalysts
Synthesis
Effect of temperature on formic acid decomposition catalyzed by the immobilized ruthenium catalysts MCM41-Si-(CH2)2PPh2/
Ru-mTPPTS. 0.10 g immobilized ruthenium catalyst containing 0.0027 mmol ruthenium, 10 M HCOOH/HCOONa (9/1) in 1 ml
aqueous solution, addition of 0.38 ml HCOOH for recycling.
W. Gan, P. J. Dyson, G. Laurenczy, ChemCatChem, 2013, 5, 3124.
W. Gan, P. J. Dyson, G. Laurenczy, EPFL-Granit SA, 2013, International Patent
39
2015
A. Dalebrook
1. Hydrogen/energy supply with iron catalysts Iron catalyst with PP3 ligand
HCOOH
→
H2 + CO2
(tris[(2-diphenylphosphino)ethyl]phosphine),
P(CH2CH2PPh2)3
in propylene carbonate solvent
TOF= 9425 h-1
TON= 92400
(from renewable
sources)
(delivery)
!
Molecular structure of the salt [FeH(PP3)]BF4
A. Boddien, D. Mellmann, F. Gärtner, R. Jackstell, H. Junge, P. J. Dyson, G. Laurenczy*, R. Ludwig*, M. Beller*, Science, 2011, 333, 1733.
40
2015
A. Dalebrook
1. Hydrogen/energy supply with iron catalysts All species identified (NMR, X-Ray, HRMS)
Proposed
mechanism
80°C
pH2 [bar]
pCO2 [bar]
TON 2h
TON 3h
0
0
225
325
10
0
97
185
20
0
73
136
0
10
235
304
0
20
225
287
0
30
223
302
80°C
80°C
122
80°C
80°C
Influence of pressure on the iron catalyzed
dehydrogenation of HCOOH
A.  Boddien, D. Mellmann, F. Gärtner, R. Jackstell, H. Junge, P. J. Dyson, G. Laurenczy*, R. Ludwig*, M. Beller*, Science, 2011, 333, 1733.
41
2015
A. Dalebrook
1. Ru(II) catalysts HCOOH
→
H2 + CO2
Ru(II)-mTPPTS in water:
C. Fellay, P. J. Dyson, G. Laurenczy, Angew. Chem. Int. Ed., 2008,
International Patent, 2006, 2013
ü  efficient
ü  generate very pure H2 (and CO2)
ü  at any wanted pressure
CO < 10 ppm
(from renewable
sources)
29
(delivery)
2015
A. Dalebrook
ü  “gas compressor”
ü in aqueous solution
ü no by-products
prototypes:
2-3 m3 H2 /h
1. Ru(II) catalysts CO2
H2
HCOOH
(delivery)
(from renewable sources)
13
2015
A. Dalebrook
C aC O 3 + H 2 O + C O 2
2.0
C a 2+ + 2 HC O 3 -­‐
2. CO2/HCO3-­‐ hydrogena9on with Ru(II) catalyst [HCOO-] /M ↑
1.5
HCO3- + H2
1.0
HCOO- + H2O
CaCO3/CO2 reduction in aqueous
solution under mild conditions
0.5
t /h
0.0
0
100
200
300
400
→
500
Typical concentration/time profile of CO2/CaCO3 reduction into HCOO- at 323 K, followed in situ by 1H
and 13C NMR. Initial conditions: CaCO3 solid= 200 mg (in 2.0 ml water), P(CO2)= 30 bar, P(H2)= 20 bar,
[Ru(II)]= 0.0026 M, shaking: 300 min-1, initial TOF= 37 h-1, TON= 626.
F. Joó, G. Laurenczy, L. Nádasdi, J. Elek, Chem. Comm., 1999, 971.
17
2015
A. Dalebrook
2. Direct CO2 hydrogena9on CO2 + H2
catalyst
HCOOH
-  direct homogeneous catalytic hydrogenation
-  in water and in DMSO
-  no additives, base is necessary
-  in acidic media
-  Ru – PTA catalyst
-  recycling
-  0.2 M HCOOH in water
-  1.9 M HCOOH ( 15 %) in DMSO
S. Moret, P. J. Dyson, G. Laurenczy, EOS Holdig/EPFL, Patent 2013
S. Moret, P. J. Dyson, G. Laurenczy, Nature Communications, 2014, 5, 4017. DOI: 10.1038/ncomms5017
18
2015
A. Dalebrook
Direct CO2 hydrogena9on In water
13C
NMR signals of DCOOD in the hydrogenation
reactions of CO2 into formic acid in D2O. [RuCl2(PTA)4]
(2.76 mM), in D2O
P = 50 bar CO2 and 50 bar H2. T= 60°C. Evolution of the
13C NMR signals of DCOOD at 166.3 ppm.
Pressure dependence on the concentration of formic acid
obtained in the catalytic hydrogenation of CO2 with [RuCl2(PTA)4]
[RuCl2(PTA)4]= 2.76 mM, P(CO2)= 50 bar, it is completed with H2 to
the desired pressure. T= 60°C.
S. Moret, P. J. Dyson, G. Laurenczy, Nature Communications, 2014, 5, 4017. DOI: 10.1038/ncomms5017
18
2015
A. Dalebrook
Direct CO2 hydrogena9on Pressure effect on the formic acid yield in DMSO.
[RuCl2(PTA)4] (2.76 mM), t= 50°C, P(H2)/P(CO2) ratio of 1.
In DMSO
Influence of the temperature on the hydrogenation of
CO2 to formic acid using [RuCl2(PTA)4] in DMSO.
Conditions: [RuCl2(PTA)4]= 2.76 mM in DMSO.
P(CO2)= 50 bar, P(H2)= 150 bar (P(H2)/P(CO2) = 3).
18
2015
Recycling
[RuCl2(PTA)4]= 2.76 mM, P= 50 bar CO2 and 50 bar H2, T=60°C
A. Dalebrook
2. Direct CO2 hydrogena9on In DMSO
Cl
Proposed catalytic cycle for the hydrogenation of carbon
dioxide with [RuCl2(PTA)4] catalyst in water or DMSO.
1H
and 1H{31P} NMR spectra of the hydride region,
[RuCl2(PTA)4]= 2.76 mM, P(total) = 100 bar, P(H2)/P(CO2)
ratio of 1, t = 50°C, in DMSO
δ= -9.2 ppm [RuH(PTA)4Cl] δ= -11.2 ppm [RuH2(PTA)4]
18
2015
PTA (P) =
A. Dalebrook
Reversible HCO3- reduction – hydrogen
generation
H2 + HCO3- Na+
HCOO- Na+ +
H 2O
200
TON
150
100
[{RuCl2(mtppms)2}2]; [Ru]=1mM; [mtppms]=4mM;
[NaHCO3]=0,2M; P(H2)=10bar; T=50°C, V=10mL
50
0
0
100
200
300
time / min
400
G. Papp, J. Csorba, G. Laurenczy, F. Joo, Angew. Chem. Int. Ed., 2011, 50, 10433.
J. Elek, L. Nádasdi, G. Papp, G. Laurenczy, F. Joó, Appl. Catal. A. 2003, 255, 59.
2015
44
A. Dalebrook
500
Reversible HCO3- reduction – hydrogen
generation
aqueous solution
80°C
40°C
G. Papp, J. Csorba, G. Laurenczy, F. Joo, Angew. Chem. Int. Ed., 2011, 50, 10433.
2015
45
A. Dalebrook
[Ru]=2 mM; [mtppms]=8 mM;
[HCO2Na]=0.24 M;
V(H2O)=5.5 mL; P(total)=1
bar
Reversible HCO3- reduction – hydrogen
generation
Formate/bicarbonate % ratio in the catalytic cycle
([Ru]=10 mM, [mtppms]=42.5 mM, [H13COONa]=
257 mM, 2 mL D2O)
a): hydrogen storage, t= 83°C, 100 bar H2;
b): hydrogen generation, t= 83°C
mtppms
G. Papp, J. Csorba, G. Laurenczy, F. Joo, Angew. Chem. Int. Ed. 2011, 50, 10433.
46
2015
A. Dalebrook
Reversible HCO3- reduction – hydrogen generation
Conversion equilibrium during consecutive
bicarbonate hydrogenation-formate
dehydrogenation cycles (t= 80°C)
K. Sordakis, A. Dalebrook, G. Laurenczy, ChemCatChem 2015, 7, 2332-2339.
46
2015
A. Dalebrook
Acknowledgements
Céline Fellay, Weijia Gan, Paul Dyson, Martin Grasemann, Séverine Moret, Katrina Kendall,
Yanick Cudre, Benoït Lorent, Frost-Penninton Ewan, Arnaud Thevenon, Cédric Liehn,
Katerina Sordakis, Andrew Delebrook, Cornel Fink, Mickael Montandon
Swiss National Science Foundation
Swiss Federal Office of Energy - OFEN
Swiss Commission for Technology and Innovation - CTI
Swiss Competence Center for Energy Research - SCCER
51
2015
A. Dalebrook
Thank you !
52
2015
A. Dalebrook