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Absence of CO2 electroreduction on copper, gold and silver electrodes without metal cations in solution


The electrocatalytic reduction of carbon dioxide is widely studied for the sustainable production of fuels and chemicals. Metal ions in the electrolyte influence the reaction performance, although their main role is under discussion. Here we studied CO2 reduction on gold electrodes through cyclic voltammetry and showed that, without a metal cation, the reaction does not take place in a pure 1 mM H2SO4 electrolyte. We further investigated the CO2 reduction with and without metal cations in solution using scanning electrochemical microscopy in the surface-generation tip-collection mode with a platinum ultramicroelectrode as a CO and H2 sensor. CO is only produced on gold, silver or copper if a metal cation is added to the electrolyte. Density functional theory simulations confirmed that partially desolvated metal cations stabilize the CO2 intermediate via a short-range electrostatic interaction, which enables its reduction. Overall, our results redefine the reaction mechanism and provide definitive evidence that positively charged species from the electrolyte are key to stabilize the crucial reaction intermediate.

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Fig. 1: CO2 reduction on gold with and without 280 μM Cs+ in solution.
Fig. 2: Effect of the Cs+ concentration.
Fig. 3: Effect of the cation identity.
Fig. 4: SECM measurement scheme and characterization of the electrodes used.
Fig. 5: CO detection with SECM.
Fig. 6: Cation coordination with CO2.
Fig. 7: CO2 activation via an explicit cation–intermediate interaction, driven by cation concentration at the OHP.
Fig. 8: Mechanism of CO2 reduction to CO.

Data availability

The datasets generated though DFT simulation and analysed during the current study are available in the ioChem-BD database (ref. 64) at (ref. 65). Experimental datasets are available from the corresponding author upon reasonable request.


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This work was supported by the European Commission (Innovative Training Network ELCoREL, 722614-ELCOREL). F.D., R.G.-M. and N.L. further acknowledge the Barcelona Supercomputing Center (BSC-RES) for providing generous computational resources.

Author information




M.C.O.M. and F.D. wrote the manuscript with input from all the authors. M.C.O.M. and M.T.M.K. designed the experiments, which were carried out by M.C.O.M. with assistance from B.H., F.D. R.G.-M. and N.L. carried out the DFT AIMD simulations. All the authors contributed to the modelling section, read and commented on the manuscript.

Corresponding author

Correspondence to Marc T. M. Koper.

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The authors declare no competing interests.

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Peer review information Nature Catalysis thanks Leanne Chen and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Discussion, Methods, Notes 1 and 2, Figs. 1–12, Tables 1–4 and Videos 1– 5.

Supplementary Video 1

DFT-based ab initio molecular dynamics of the Au-H2O-CO2 system.

Supplementary Video 2

DFT-based ab initio molecular dynamics of the Au-H2O-Li+-CO2 system.

Supplementary Video 3

DFT-based ab initio molecular dynamics of the Au-H2O-Na+-CO2 system.

Supplementary Video 4

DFT-based ab initio molecular dynamics of the Au-H2O-K+-CO2 system.

Supplementary Video 5

DFT-based ab initio molecular dynamics of the Au-H2O-Cs+-CO2 system.

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Monteiro, M.C.O., Dattila, F., Hagedoorn, B. et al. Absence of CO2 electroreduction on copper, gold and silver electrodes without metal cations in solution. Nat Catal 4, 654–662 (2021).

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