Journal Article

FZJ-2023-03708

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Interplay of Local pH and Cation Hydrolysis during Electrochemical CO 2 Reduction Visualized by In Operando Chemical Shift-Resolved Magnetic Resonance Imaging

Schatz, M. (Corresponding author)FZJ*RWTH* ; Kochs, J. F.FZJ*RWTH* ; Jovanovic, S.FZJ* ; Eichel, R.-A.FZJ*RWTH* ; Granwehr, J.FZJ*RWTH*

2023
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/acs.jpcc.3c03563  doi:10.34734/FZJ-2023-03708

Abstract: The Cu-catalyzed electrochemical CO2 reduction enables the conversion of greenhouse gas emissions to fuels or platform chemicals with prospects of storing intermittent energy from renewable sources. While current research in tuning catalyst activity and product selectivity is often mired in finding electrode engineering solutions, the importance of electrolyte engineering is mostly overlooked. This study presents a method for measuring local pH profiles in electrode proximity and correlating them to cation-induced buffering effects. Magnetic resonance imaging (MRI) techniques were applied to evaluate the local pH values using spatially resolved 13C resonances of the CO2/HCO3–/CO32– equilibrium. The buffering effect of cation hydrolysis is substantiated by local shifts of the 23Na resonance of Na+ in the NaHCO3 electrolytes. Steeper local pH gradients, compared to experiments with KHCO3, account for increased selectivity for acetate formation from the solution-based reaction. Proven itself capable of elucidating the effect of cations on local pH values, our presented method supports tailoring the electrode–electrolyte interface to selectively generate value-added products.

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Contributing Institute(s):

1. Grundlagen der Elektrochemie (IEK-9)

Research Program(s):

1. 1232 - Power-based Fuels and Chemicals (POF4-123) (POF4-123)
2. HITEC - Helmholtz Interdisciplinary Doctoral Training in Energy and Climate Research (HITEC) (HITEC-20170406) (HITEC-20170406)

Appears in the scientific report 2023

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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