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  • Synergistic Effects of the Electric Field Induced by Imidazolium Rotation and Hydrogen Bonding in Electrocatalysis of CO 2
Title: Synergistic Effects of the Electric Field Induced by Imidazolium Rotation and Hydrogen Bonding in Electrocatalysis of CO 2
The roles of the ionic liquid (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]), and water in controlling the mechanism, energetics, and electrocatalytic activity of CO2 reduction to CO on silver in nonaqueous electrolytes were investigated. The first electron transfer occurs to CO2 at reduced overpotentials when it is trapped between the planes of the [EMIM]+ ring and the electrode surface due to cation reorientation as determined from voltammetry, in situ surface-enhanced Raman spectroscopy, and density functional theory calculations. Within this interface, water up to 0.5 M does not induce significant Faradaic activity, opposing the notion of it being a free proton source. Instead, water acts as a hydrogen bond donor, and the proton is sourced from [EMIM]+. Furthermore, this study demonstrates that alcohols with varying acidities tune the hydrogen bonding network in the interfacial microenvironment to lower the energetics required for CO2 reduction. The hydrogen bonding suppresses the formation of inactive carboxylate species, thus preserving the catalytic activity of [EMIM]+. The ability to tune the hydrogen bonding network opens new avenues for advancing IL-mediated electrocatalytic reactions in nonaqueous electrolytes.  more » « less
Award ID(s):
2045111 1904592
PAR ID:
10533329
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
Journal of the American Chemical Society
ISSN:
0002-7863
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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