The document presents research on electrochemical reduction of CO2 in various acid and neutral media, focusing on factors such as electrolytes, current density, and ion effects. It highlights the comparison of carbon efficiency between alkaline and acidic media and evaluates the role of cations in enhancing CO2 activation kinetics. Additionally, it includes a techno-economic assessment of CO2 reduction systems and the performance of specific materials used in the process.

1. Literature Presentation
Debabrata Bagchi
Ph. D. Student
11/09/2021
Electrochemical CO2 reduction in
Acid medium
1

2. 1
Prof. Sargent
3
Prof. Sinton
2
Prof. Fengwang
1-3:University of Toronto, Canada; 2:University of Sydney.

3. CO2RR in basic, acid & neutral media
3
Acidic electrolyte
Neutral/alkaline
electrolyte
CO2RR in flow cell
Adv. Funct. Mater. 2021, 2102151
(CEM, nafion)
(AEM, fumasep)

4. CO2RR in Flow cell and MEA
4
Alkaline Flow Cell Neutral Flow Cell MEA Electrolyzer
Joule 2019, 3, 2777–2791

5. 5
Alkaline vs. Acidic Electrolyte
Carbon efficiency in
alkaline media is lower
than in neutral media
owing to additional
consumption of CO2 by
bulk OH–

6. 6
Which is good electrolyte
Acid
Neutral Alkaline
(H+)
(CO3
-) (OH-)
High Current
High CO2RR yield
Low carbonate formation
High CO2RR yield
Moderate CO2RR yield
Goal

7. 7
Acidic Electrolyte
Acid with CEM @400 mA/cm2

8. 8
CO2 crossover tests in different electrolytes
1 M KHCO3 with AEM 0.5 M H3PO4 + 0.5 M KH2PO4 with CEM
Acid with CEM Acid with CEM

9. 9
Cation augmenting
strategy to improve CO2
activation kinetics in
strong acid
Central concept

10. 10
Modelling of pH near the cathode
pH 1.94 pH 3.02 pH 3.96
pH 2 pH 3 pH 4
H3O+ mass transport limitation occurs and H2O becomes the main proton donor
at the cathode surface

11. 11
Effect of KCl addition
Faradaic efficiency on sputtered Ag with
different KCl concentrations
200 mA/cm2

12. 12
Effect of K+ addition
(A) 1 M H3PO4. (B) 1 M H3PO4 + 1 M KCl. (C)
1 M H3PO4 + 2 M KCl. (D) 1 M H3PO4 + 3 M KCl
At current densities <200 mA/cm2
K+ does not play a role in the
activation of CO2 nor does it suppress HER
in a locally acidic environment

13. 13
Cation-enabled CO2 reduction in acid
1M H3PO4 at 400 mA/cm2
1 M H3PO4 and 3 M KCl
on Cu
1 M H3PO4 and 3 M KCl
Tafel slope analysis

14. 1M H3PO4
+2 M KCl
14
Role of K+ on HER and CO2RR
Total 400 mA/cm2
+1 M KCl
+3 M KCl
Under a proton-depletion local environment, the
cation triggers CO2 activation,

15. 15
Control study: Effect of anions on CO2RR
@ 400 mA/cm2
In-situ EXAFS
K+ is not changing electronic state of Cu
Overall activity
How to get more K+
near electrode surface
?

16. 16
Use of Cation-augmenting layer (CAL)
v
FE at
different J
perfluorosulfonic acid

17. 17
XPS of CAL

18. 18
CuNPs/PFSA composite material
1 M KCl 2 M KCl 3 M KCl
CO2R selectivity reached
61%, including a total C2+FE of 40%

19. 19
Extended CO2R performance
Current density of 1.2 A cm−2 1 M H3PO4 + 3 M KCl

20. 20
Operational cost breakdown of neutral CO2RR MEA electrolyzer
and alkaline flow-cell electrolyzer in ideal scenario

21. 21
Techno-economic assessment of neutral CO2R MEA electrolyzer
and alkaline flowcell electrolyzer, together with specific cost
distribution per ton of ethylene produced
Acid
High Current
High CO2RR yield
No carbonate formation

22. 22