Electrolyte engineering for electrochemical CO2 reduction
Résumé
Ionic liquids (ILs) in electrocatalysis have attracted a lot of attention from the seminal work of Rosen
et al. [1] where they achieved a relevant overpotential decrease for CO2 reduction reaction (CO2RR) on
a silver electrode. Moreover, ILs have been proposed as organic promoters for enhancing the catalytic
activity by modifying the electrostatic properties at the electrochemical interface. Then, electrolyte
engineering has become a powerful way to impact on the stability of reaction intermediates and
control reaction selectivity.
The role of different ILs as simultaneous supporting electrolyte and co‐catalyst in acetonitrile for CO2
electroreduction in the presence of a model molecular catalyst [Re(bpy)(CO)3Cl] is presented here. [2]
In particular, the nature of the cation, anion and cation alkyl chain is varied by a choice of 5 different
ILs, including imidazolium and pyrrolidinium cations and their results are compared to conventional
benchmark supporting electrolyte. Under catalytic conditions an overpotential diminution of 0.33 V
for CO2 to CO conversion is achieved in the presence of ILs. Finally, a mechanistic explanation is
provided to justify this behaviour.
[1] Rosen, B.A.; Salehi‐Khojin, A.; Thorson, M.R.; Zhu, W.; Whipple, D.T.; Kenis, P.J.A.; Masel, R.I.
Science 2011, 334 (6056), 643.
[2] Vichou, E.; Xu‐Li, Y.; Gomez‐Mingot, M.; Fontecave, M.; Sánchez‐Sánchez, C.M. J. Phys. Chem. C
2020, 124, 23764.