Carbon-13 Nuclear Magnetic Resonance Spectroscopy: Carbon-13 Chemical Shifts and Coupling Constants

Mooney, E.F.; Winson, P.H.

doi:10.1016/s0066-4103(08)60322-1

Cited by 23 publications

(5 citation statements)

References 189 publications

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“…We further pulse electrolyzed 13 C-labeled K 2 13 CO 3 and detected H 13 COO − at δ = 8.15 and 8.54 with 1 H NMR. 45 This confirms that the carbon source of formate is from K 2 13 CO 3 , rather than from dissolved CO 2 from the atmosphere. Control pulse electrolysis was also conducted on an OD−Cu catalyst in N 2 -saturated 0.1 M KOH.…”

Section: Direct Reduction Of Cu 2 (Co 3 )(Oh)mentioning

confidence: 63%

Direct Electroreduction of Carbonate to Formate

Ma,

Ibáñez Alé,

López

et al. 2023

Meet. Abstr.

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A cause of losses in energy and carbon conversion efficiencies during the electrochemical CO2 reduction reaction (eCO2RR) can be attributed to the formation of carbonates (CO3 2–), which is generally considered to be an electrochemically-inert species. Herein, we employ in-situ electrochemical Raman spectroscopy, liquid chromatography, nuclear magnetic resonance spectroscopy, 13C isotope-labelling and density functional theory (DFT) simulations to understand the role of carbonate species formed on copper catalysts during eCO2RR, and its ability to reduce to formate. Direct carbonate-to-formate conversion was confirmed by the the direct reduction of CuCO3, and by pulse reduction of N2-saturated K2CO3 electrolyte on Cu,. DFT simulations elucidated the nature of the active sites generating the Cu-CO3 2– species and revealed the mechanism for the pulse-enabled carbonate reduction to formate. Combining both experimental and computational results, we proposed that a dynamic carbonate intermediate was constantly formed on Cu during eCO2RR, that further evolves to formate between –0.4 to –1.2 VRHE on Cu. Control systems using Pb, Ag and Au electrodes were also studied.

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Section: Direct Reduction Of Cu 2 (Co 3 )(Oh)mentioning

confidence: 63%

Direct Electroreduction of Carbonate to Formate

Ma,

Ibáñez Alé,

López

et al. 2023

Meet. Abstr.

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“…This indicates that the formation of the Cu–CO 3 2– species, occurring at −0.05 V RHE , is necessary for the conversion of CO 3 2– to formate. We further pulse electrolyzed 13 C-labeled K 2 13 CO 3 and detected H 13 COO – at δ = 8.15 and 8.54 with 1 H NMR . This confirms that the carbon source of formate is from K 2 13 CO 3 , rather than from dissolved CO 2 from the atmosphere.…”

Section: Results and Discussionmentioning

confidence: 99%

Direct Electroreduction of Carbonate to Formate

Ma,

Ibáñez-Alé,

Ganganahalli

et al. 2023

J. Am. Chem. Soc.

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A cause of losses in energy and carbon conversion efficiencies during the electrochemical CO 2 reduction reaction (eCO 2 RR) can be attributed to the formation of carbonates (CO 3 2− ), which is generally considered to be an electrochemically inert species. Herein, using in situ Raman spectroscopy, liquid chromatography, 1 H nuclear magnetic resonance spectroscopy, 13 C and deuterium isotope labeling, and density functional theory simulations, we show that carbonate intermediates are adsorbed on a copper electrode during eCO 2 RR in KHCO 3 electrolyte from 0.2 to −1.0 V RHE . These intermediates can be reduced to formate at −0.4 V RHE and more negative potentials. This finding is supported by our observation of formate from the reduction of Cu 2 (CO 3 )(OH) 2 . Pulse electrolysis on a copper electrode immersed in a N 2 -purged K 2 CO 3 electrolyte was also performed. We found that the carbonate anions therein could be first adsorbed at −0.05 V RHE and then directly reduced to formate at −0.5 V RHE (overpotential of 0.28 V) with a Faradaic efficiency of 0.61%. The nature of the active sites generating the adsorbed carbonate species and the mechanism for the pulse-enabled reduction of carbonate to formate were elucidated. Our findings reveal how carbonates are directly reduced to a high-value product such as formate and open a potential pathway to mitigate carbonate formation during eCO 2 RR.

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“…However, sensitivity enhance-ment (36 -39) optimized for IS spin systems is imple-scans in this cycle, the relevant product-operator terms excited at point c in the sequence are given by terms A mented in sequence 3c. Since the one-bond coupling can be assumed to be positive (47,48), the signs of the other couplings result from the tilt of the respective cross-peak pattern. For the first and second group of four and B of Eq.…”

Section: Introductionmentioning

confidence: 99%