Journal Article

FZJ-2026-00903

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Mapping proton and carbon dioxide electrocatalytic reductions at a Rh complex by in situ spectroelectrochemical NMR

Kick, A.-C. (Corresponding author) ; Schatz, M.FZJ* ; Kahl, C. ; Hölscher, M. ; Eichel, R.-A.FZJ*RWTH* ; Granwehr, J.FZJ*RWTH* ; Kaeffer, N. ; Leitner, W. (Last author)

2026
RSC Cambridge

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Please use a persistent id in citations: doi:10.1039/D5SC05744B  doi:10.34734/FZJ-2026-00903

Abstract: Detailed molecular level understanding of organometallic electrocatalytic systems is required to fully exploit their technological potential to store, distribute, and utilise renewable energy in chemical form. However, in situ methods providing high resolution information on the structure and reactivity of transient intermediates remain challenging due to incompatible requirements for standard electrochemical and spectroscopic cell designs. Here, we demonstrate the use of spectroelectrochemical nuclear magnetic resonance (SEC-NMR) to enable operando characterisation of molecular species during organometallic electrocatalysis. The electroreduction of a prototypical molecular rhodium(+I) diphosphine complex was studied under aprotic conditions and in the presence of H2O and/or CO2. By combining multinuclear SEC-NMR, chemical reductions, modelling and simulations, we determine the involved species, their relative concentrations and the competing interconversions. The bielectronic reduction leading to the highly reactive low-valent rhodium(−I) intermediate and subsequent protonation of that species into a Rh–hydride complex was followed in a time-resolved manner. Deuterium labelling and ex situ NMR analysis after SEC-NMR electrolysis revealed that under aprotic conditions the proton source substantially arises from Hofmann elimination of the nBu4NPF6 electrolyte in addition to the acetonitrile solvent. The reactivities of the Rh(−I) and the Rh–H complexes were further monitored under turnover conditions, providing direct molecular insights into bifurcating electrocatalytic pathways for hydrogen evolution and CO2 reduction.

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Contributing Institute(s):

1. Grundlagen der Elektrochemie (IET-1)

Research Program(s):

1. 1232 - Power-based Fuels and Chemicals (POF4-123) (POF4-123)
2. DFG project G:(GEPRIS)390919832 - EXC 2186: Das Fuel Science Center – Adaptive Umwandlungssysteme für erneuerbare Energie- und Kohlenstoffquellen (390919832) (390919832)

Appears in the scientific report 2026

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Database coverage:
; ; ; ; Chemical Reactions ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Essential Science Indicators ; IF >= 5 ; Index Chemicus ; JCR ; National-Konsortium ; PubMed Central ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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