Plenary lecture given by Joan Ramón Morante (IREC) at the XVII B-MRS Meeting, in Natal (Brazil), on September 20, 2018.

1. Catalyst materials for solar refineries, synthetic fuels and
procedures for a circular economy of the CO2
J.R.Morante
IREC, Catalonia Institute for Energy Research, Plaça de les Dones de Negre,1.
Sant Adrià del Besòs, 08930. Spain.
Department of Electronics, University of Barcelona, C/Martí i Franquès,1.
Barcelona,08028. Spain.
H2
O2

2. Nowadays, the circular economy of carbon dioxide constitutes
one of the major world challenges.
Climatic change
CO2 emissions

3. The conversion of CO2 into value-added chemicals and/or fuels, using
renewable energy and earth-abundant elements as well as environmental
friendly materials is a key priority.

5.  Carbon dioxide closed loop in which this molecule is captured,
reduced and oxidized continuously defining an ideal circular
economy of the CO2
Fossil gas
CO2 emissions
Methanation based on
Paul Sabatier reactor.

6. Closed loop CO2-CH4

7.  Carbon dioxide reduction by thermochemical or plasma
procedures which are open new alternatives to the
methanation process
Patent: P201530109
300mg of catalyst,
corresponding to an GHSV of
20000, the reactor is supplied
with a mixture of carbon dioxide
and hydrogen (20% vol CO2)
with a total flow rate of 12000
ml/h), at atmospheric pressure
and at temperature of 20°C
Journal of CO₂ Utilization 26 (2018) 202–211

8. EELS chemical composition maps obtained from the red
rectangled area of the STEM-HAADF micrograph. Individual Ce
(red), Zr (green) and Ni (blue) maps and their composite. It
should be noted here that we have normalized the intensity
values of the maps to that of Ce to have a better comparison

9. Mesoporous

11. Bioconversion: Synthetic natural gas production from biogas in
a waste water treatment plant
In collaboration with Naturgy
programa RIS3CAT
ENERGY CONVERSION AND MANAGEMENT
162 pp 218-224 (2018)

12. Demonstration unit [Sabadell (Barcelona) Spain)
Digestor
GasometerBiogas

13. Methanation unit
CO2 + 4H2 –> CH4 + 2H2O
Alkaline electrolyzer
37 kWh
Biogas source (55-65% CH4)
H2S cleaning
CH4
CO2
CO2 source
10 Nm3/h

14. Methanation reactors
Compact
reactor technology
Quick start-up
and shut-down times
Load-flexibility
T depends on time, length T < 500ºC
High technology

15. Injectable conditions in the gas pipeline are achievable in Sabadell
stream H2 CH4 CO2 XCO2
% % % %
inlet 66 - 33 0
middle 30 65 10 90,85
outlet 4,4 95,4 0,2 99,77
Electric consumption SNG production Efficiency PtG XCO2
kWh Nm3/h kWh/Nm3 kWout/kWin %
Test 1 16,24 0,577 28,15 38,06 96,99
Test 2 15,84 0,536 29,58 36,13 97,75
Test 3 12,16 0,519 23,00 46,55 97,61
kWout/kWin > 50% can be
achieved within this project
85-95% power consumption comes from hydrogen production,
nevertheless surplus renewal energy production can be used.
Performant
catalysts are
the clue

16. Fin de semana
Intermedia
Carga
Punta
Base
Eólica
Fotovoltaica
Demanda
Solar concentración
Carga
21% RENEWABLE
SURPLUS OF ENERGY
ENERGY
CONSUMPTION
DURING A WEEK
60% renovables
WIND
ENERGY
SOLAR
ENERGY
WITHOUT
RENEWABLES

17. http://www.grtgaz.com/fileadmin/transition_energetique/documents/hydrogene_et_reseau_e-
cube_GRTgaz.pdf
http://www.grtgaz.com/fileadmin/engagements/documents/fr/Power-to-Gas-etude-ADEME-GRTgaz-GrDF-
complete.pdf

18. Source: IRES (Fraunhofer presentation) + IREC

19. Methanation: Solar Hydrogen +CO2
Renewable energy +feed stocks (H2, CO2)
100%
Feed stocks managements
95% Efficiency 95%; loss 5%
Methanation
76% Efficiency 80%; loss 19%
Compressor, storage and CH4 pipe
74,5% Efficiency 98,5%; loss 1.5%
Gas transport (500Km)
Efficiency 99,55%, loss 0,37%
74,1%
Methanation: Solar
Hydrogen+CO2

20. Dark
(or under illumination)

21. Carbon dioxide reduction by electrochemical (dark and photo)
procedures NEW RESEARCH
ALTERNATIVE
DARK PHOTO
Reduced
CO2 products
High current
densities
Centralizer
electrolyzer.
Current
densities of
PV cell.
Distributed
electrolyzer.
Future depends on cost
and social acceptation

22. Dark
Under illumination
PHOTO
EFFECT
Two challenges:
• Current density
• Bias reduction

23. efficient solar induced bias free working mode of a PEC cell
If curves intersect, there is enough
potential for bias free working
mode of the cell.
All that matters is the current Jop at
the intersection.
Source: several+IREC
E red E oxd

24. Hybrid photoanode-photocathode device for bias-free water splitting
Photoanode: Hematite, TiO2
Photocathode:
• a-Si:H tandem with Ni as HER catalyst
• a-Si:H/a-Si:H/µc-Si:H triple with Ni catalys
Electrolyte: 1M NaOH
Stability of stand-alone
hybrid Hematite/Tandem device
2-electrode config.
0 V applied biashematite
a-Si:H tandemO2
H2
To be published

25. Data source: F. Urbain et al. 2016&2018

26. System consists of two polymer electrolyte membrane electrolysers in series
with one InGaP/GaAs/GaInNAsSb triple-junction solar cell, which produces a
large-enough voltage to drive both electrolysers with no additional energy
input. The system achieves a 48-h average STH efficiency of 30%
Nat Comm 2016,7,13237
Very expensive
Use scarce
materials.

27. The TiO2-protected III–V tandem
device exhibited a solar-to-hydrogen
conversion efficiency, STH, of
10.5% under 1 sun illumination, with
stable performance for > 40 h
Energy Environ. Sci.,
2015, 8, 3166

28. 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
0
5
10
15
20
IBC UPC +Ni epox + Ni/Pt PEC H2SO4
IBC UPC +Ni epox + Ni/Pt PV
HC-STH(%)
E (V vs RHE)
50cm2 area
0,650
40mA/cm2
STH >15%
PATENT:15382658.1
PEC
PV
ACS APPLIED MATERIALS & INTERFACES 10
(16) pp: 13425-13433 (2018)
Our results:

29. Artificial
photosynthesis:
solar refinery

30. Photons
Fuel
Added Value Chemicals
Solar heat
Solar electricity
H2O pipeline
CO2 pipeline
Activation Mechanisms for
H2O and CO2 reduction
Fossil fuel
power plant
Fischer Tropsch
Water
Thermo-chemical
Thermolysis
Photolysis
Photo-catalysis
CO2
Capture
Photo-electro-chemical
Electro-chemical
Solar Refinery
Chemical Storage & CO2 Circular Economy
biogenic carbon

31. Electrolyzers/
Co-electrolysis
.
12-20%
>10%
< 65% operation
Solar fuels
<1€/Wp
<6c€/kWh < 6c€/Kwh
photons
electrons chemicals
Data source: IREC

32. centralized
or
distributed
Where and how to install the
electrochemical part?
20%
19%
11%
20%
> 17%
> 17%

33. ELECTRICIDAD GAS

34. Overpotentials at several
tens of mA/cm2 ?
Overpotentials at several
tens of A/cm2 ?
Electrodes:
Voltage cell:
LHV 1,23/1,5 ~ 82%
HHV 1,48/1,5 ~ 98%
1,23/2,3 ~ 55%
Less transportation losses
Example
considering H2

35. PEC/EC ANODEEC CATHODE
3D
Nanostructured
Cathode
with Catalyst
Strong interest in
having back
illumination especially
for replacing
electroreduction
by
photoelectroreduction
of
CO2.
ELECTROCHIMICA ACTA
240 pp 225-230 (2017)
For CO2: Cathode with
appropriate catalyst
Anode with excellent OER.

36. The final energy balance as well as the
overall efficiency and productivity depend,
aside of the system design constraints, of
parameters as the over-potential values,
charge transfer resistances linked to the
role played by the catalyst.
ELECTROCHIMICA ACTA 240 pp 225-230 (2017)
PATENT: P3146EP00 PEC system for solar fuels

37. Carbon dioxide can give rise to different reduction reactions
pathways with several sub products. .
CO2 Reduction Products
CO2 + 2e-  •CO2
-
CO2 + 2H+ + 2e-  HCOOH
CO2 + 2H+ + 2e-  CO + H2O
CO2 + 4H+ + 4e-  HCHO+ H2O
CO2 + 6H+ + 6e-  CH3OH+ H2O
CO2 + 8H+ + 8e-  CH4 + 2H2O
2H2O + 4h+  O2 + 4H+
2H+ + 2e-  H2

38. CO2
Electrocatalysts reduce the overpotential of reactions through formation of
intermediates. Therefore, elucidating the intermediates is a crucial requirement
for rational design of novel catalysts that overcome the current limitations.
So, one of the objective must tackle this knowledge gap by high-risk–high-gain
approaches to prepare catalytic intermediates on oxides

39. CO2 reduction by metal electrocatalysis
*Source : J. Chem. SOC., Faraday Trans. I, 1989, 85(8), 2309-2326
Chem. Asian J. 2009,4, 1516-1523
 Stabilization of CO2
•–
intermediate = high
energy efficiency.
 Three groups
depending on the
binding strength
+
High HER
overpotential
CO desorption
before
reduction
+
Low HER
overpotential
HCOOH
formation
Weak CO adsorption
Strong CO
adsorption
+
Low HER
overpotential
CO poisoning
Optimum CO adsorption
CO reduction
Intermediate steps of CO2R
i.e. protonation *CHO or *COH
2
1
3
1

40. Gas Diffusion Electrodes
Electrolyte
Planar
Planar electrode Gas diffusion electrode
Catalyst particles
Electrolyte
CO2
chamber
GDE
• Active surface area ≈ geometric surface area
• Limited CO2 solubility = Mass transfer problem
• Active surface area >> geometric surface area
• Improved CO2 transfer = overcome solubility
problem

41. Toray Carbon Paper TGP-H-60 after Cu deposition
JOURNAL OF PHYSICAL CHEMISTRY C
119 ,33 , pp18835-18842 (2015)

42. fibers after deposition of Sn
APPLIED CATALYSIS B-ENVIRONMENTAL
150 pp 57-62 (2014)
INTERNATIONAL JOURNAL OF HYDROGEN
ENERGY 38,7, 2979-2985 (2013)
APPLIED PHYSICS LETTERS 99 ,26 ;262102 (2011)

43. Electrodeposited Sn in GDE
E. Irtem, J.R. Morante, et al. J. Mater. Chem. A. 2016, 4, 13582.
Dark Electrolysis
Sn catalyst  Formic acid

44. Dark Electrolysis
Sn catalyst  Formic acid
• F.E.% HCOO− = 71 ± 1.1 %
• F.E.% HCOO− + CO = 82 ± 2.0 % of total CO2 conversion (CO: 6 ± 4.5 %)
• Low Tafel slope value = faster charge transfer of CO2 reduction on Sn-GDE
• Evidence of a rapid transfer of the initial electron
• Evidence of a different rate determining step = concurrent proton−electron uptake
𝑭. 𝑬. % =
𝑛 · 𝐹 · [𝐶
𝐼 · 𝑡
-0.4 -0.6 -0.8 -1.0 -1.2
0
20
40
60
80
100
HCOO
CO
E (VRHE
)
FaradaicEff.(%)
H2
-2 -1 0
-0.3
-0.4
-0.5
-0.6
-0.7 H2
254 mV dec
-1
E(VRHE
)
log ji
(mAcm-2
)
-3 -2 -1 0
-0.4
-0.5
-0.6
-0.7 HCOO
89 mVdec-1
CO
78 mVdec-1
E(VRHE
)
log ji
(mAcm-2
)
E. Irtem, J.R. Morante, et al. J. Mater. Chem. A. 2016, 4, 13582.

45. 100 1000 10000
10
100
1000activity(mol/(g*s))
grain radius (nm)
Pulsed Electro Deposition
different duty cycle
Continuous Electrodeposition
different samples
slope -1
Using other catalysts
for formic acid
submitted

46. JOURNAL OF MATERIALS CHEMISTRY A ,
4, 35, pp 13582-13588 (2016)

47. CO2 + 2e-  •CO2
-
CO2 + 2H+ + 2e-  HCOOH
CO2 + 2H+ + 2e-  CO + H2O
CO2 + 4H+ + 4e-  HCHO+ H2O
CO2 + 6H+ + 6e-  CH3OH+ H2O
CO2 + 8H+ + 8e-  CH4 + 2H2O
2H2O + 4h+  O2 + 4H+
2H+ + 2e-  H2
CO2 Reduction Products
Syngas
H2:CO ratio
3:1 Ammonia
2:1 Methanol
1:1 Oxo products
1:0 Hydrogen
...
...
...

48. CO2 Reduction Catalysts
Zn
J. Lee, et al. Chem. Asian J. 2009, 4, 1516-1523.
Syngas

49. Electrodeposition of Zn on Cu Foam
bare Cu foam 1M ZnSO4
Cu foam coated with ZnZn flakes
CE
foam

50. Structural Analysis of Zn Flakes
Zn
ZnO
Zn

51. High activity towards
CO2 reduction
Electrochemical Characterization
after 1 h electrolysis
Good stability in 0.5 M
KHCO3
F. Urbain, J.R. Morante, et al. Energy Environ. Sci. 2017, 10, 2256.
J.R. Morante et al. Energy and Environmental Science10(10), pp. 2124-2136 (2017)

52. 5:1 ≥ H2:CO ≥
0.5:1
FEmax (CO) = 85 %
jCO = 39.4 mA/cm2
Electrochemical Characterization
F. Urbain, J.R. Morante, et al. Energy Environ. Sci. 2017, 10, 2256.

53. CO2 Reduction Catalysts
Zn
J. Lee, et al. Chem. Asian J. 2009, 4, 1516-1523.
Syngas

57. ACS applied materials and interfaces (2018)
ENERGY & ENVIRONMENTAL
SCIENCE 10 , 10, 2256 (2017)

58. Dark and Solar CO2 Reduction Device
Role of the anode

59. V
[H2(g)]
[CO(g)]
e-
h+
OH-
Na+
O2
Working Mode of Stack Flow Cell
CATHODE | CO2 reduction reaction (CO2R)
CO2 aq. +2H+
+ 2e−
⟶ HCOOH(aq.)
ANODE | H2O oxidation reaction (OER) H2O l ⟶ 2H+
+ 1
2
O2 g + 2e−
CELL REACTION 𝐂𝐎 𝟐 𝐠 + 𝐇 𝟐 𝐎 𝐥 ⟶ 𝐇𝐂𝐎𝐎𝐇(𝐚𝐪.) + 𝟏
𝟐
𝐎 𝟐 𝐠
Gas
Pure CO2
0.5 M NaHCO3
0.1 M KHCO3
0.1 M KHCO3
0.5 M KOH
0.1 M KHCO3
0.1 M KOH
Membrane
Catholyte AnolyteNafion (CEM/Na+)
Selemion (AEM/OH-)
Nafion (CEM/Na+)
Sn-GDE
Cu-GDE
Cathode
Metal oxide as
TiO2 NRs/FTO or
Other PV materials
and nanostructures
Anode
ELECTROCHIMICA ACTA
240 pp 225-230 (2017)

60. 0,0 0,4 0,8 1,2 1,6 2,0
5
10
15
20
25
30
35currentdensityj[mA/cm2
]
0.5 m KOH
20 mV/s
potential E vs. RHE [V]
Energy Environ. Sci.,
8, 3242-3254, (2015)
ACS Appl. Mater.
Interfaces, 2016, 8, 4076
SOLAR ENERGY
MATERIALS AND
SOLAR CELLS
158 pp. 184-188 (2016)
ACS CATALYSIS 8, 4,
pp3331-3342 (2018)
JOURNAL OF
PHYSICALCHEMISTRY
C 122,6,pp 3295-3304 (2018)
ENERGY&ENVIRONMENTAL
SCIENCE 10, 10, 2124(2017)
ACS APPLIED MATERIALS&
INTERFACES 9 ,21,17932 (2017)
SOLAR ENERGY MATERIALS
AND SOLAR CELLS
159 ,456-466 (2017)
APPLIED CATALYSIS
B-ENVIRONMENTAL
189 pp133-140 (2016)

61. DARK
LIGHT
JOURNAL OF PHYSICS D-APPLIED PHYSICS
50 ,10, 104003 (2017)
JOURNAL OF MATERIALS CHEMISTRY A
4 ,42, pp 16706-16713 (2016)
JOURNAL OF MATERIALS CHEMISTRY A
2 ,32, pp 12708-12716 (2014)

62. CoFe nanoparticles are prepared by
1 mmol Iron acetylacetonate
1mmol Cobalt acetylacetonate ,
10 ml oleylamine,
1.0 ml oil acid mixed in a three-neck flask.
The solution was increased to 80 °C and
degased for 1hour. Then the temperature was
increased to 230°/ 300º with continuously
nitrogen pumping and maintained at the
selected temperature for 0.5 h.
After reaction, the received samples were
thoroughly purified by precipitation and
redispersion steps.
CHEMSUSCHEM 11, 1, pp 125-129 (2018)
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
138, 49 pp 16037-16045 (2016)
ACS APPLIED MATERIALS & INTERFACES
8, 43,pp 29461-29469 (2016)
ACS APPLIED MATERIALS & INTERFACES
8,27,pp 17435-17444 (2016)

64. 0 2 4 6 8
20
30
40
50
60
70
80
90
100
mA
numer of dips/ mg
dips
mg
Particles size <8nm

65. Our
CoFe

66. CoFe on Ni
foam: Our
results Ƞ (EC)= 1,23/1,5= 82%
Ƞ (PV)= 23%
Ƞ total > 18,86%
10mA/cm2
Conclusions:
advances in catalysis help to
implement new technologies to
develop an eficient low cost circular
CO2 economy.
NATURE ENERGY | VOL 1 | MAY 2016 | 1-8

67. Research must bring
solutions to have VERY LONG
STABILITY . it IS
A KEY Issue for pec systems
and it depends on the
material developers
New materials, specially
catalysts, for Dark or Photo
electrolysis of CO2 will deploy
many new disruptive ideas in the
field of energy
Science must guide the new
energy challenges of our
society

68. Catalonia Institute
for
Energy Research
New call for PhD EU
program Marie Curie
https://projects.icmab.es/docfam/
jrmorante@irec.cat

69. Thank you.
Thanks to:
Teresa Andreu
F. Urbain
J.Arbiol
Pengyi Tan
C.Ros
N.Carretero
M. Biset