Electrocatalytic reduction of CO2 in neat and water-containing imidazolium-based ionic liquids

Acknowledgements The support of the University of Aberdeen and the Leverhulme Trust (Grant RPG-2015-040) is gratefully acknowledged.Peer reviewedPostprin

In Situ Monitoring Using ATR-SEIRAS of the Electrocatalytic Reduction of CO2 on Au in an Ionic Liquid/Water Mixture

ACKNOWLEDGMENTS The support of the University of Aberdeen and the Leverhulme Trust (Grant RPG-2015-040) is gratefully acknowledged.Peer reviewedPostprintPostprin

Water-in-salt environment reduces the overpotential for reduction of of CO2 to CO2 : in ionic liquid/water mixtures

ACKNOWLEDGMENT We are grateful for funding support from the National Natural Science Foundation of China (Grants Nos 21861132015, 21991151, 21991150, 22021001, 91745103, 92161113, 91945301 and 3502Z20203027). The support of the Leverhulme Trust (RPG-2015-0400) is gratefully acknowledged. We are also very grateful to the reviewers for their helpful suggestions to improve readability.Peer reviewedPostprin

How cations determine the interfacial potential profile : Relevance for the CO2 reduction reaction

Acknowledgements The continuous support of the University of Aberdeen and financial support from the Leverhulme Trust through Research Grant RPG-2015-040 is gratefully acknowledged. A.C. and G.H. acknowledge the support of Universities UK international (UUKi) and the Department for Business, Energy & Industrial Strategy (BEIS) for a Rutherford Strategic Partner Grant (RF-2018-79) and a Rutherford Fellowship, respectively. J.C. is grateful for the financial support by the National Natural Science Foundation of China (Grants Nos. 2181101075 and 21621091), and J.L. thanks the China Postdoctoral Science Foundation (2018M642563) for support.Peer reviewedPostprintPostprin

In Situ Monitoring Using ATR-SEIRAS of the Electrocatalytic Reduction of CO₂ on Au in an Ionic Liquid/Water Mixture

The electrochemical reduction of CO₂ to CO in ionic liquids and ionic-liquid/water mixtures has received considerable attention due to recent claims of extraordinarily high energy efficiencies. We report here a study of CO₂ electroreduction on Au in an [EMIM]­BF₄/H₂O mixture (18% mol/mol) combining cyclic voltammetry and surface-enhanced infrared absorption spectroscopy in the attenuated total reflection mode (ATR-SEIRAS). The onset of the reduction current in the CV coincides with a decrease of the interfacial CO₂ concentration, but the appearance of adsorbed CO (CO_ad) is slightly delayed, as CO must probably first reach a minimum concentration at the interface. Comparisons with spectra collected in the absence of CO₂ and in CO-saturated electrolyte reveal that the structure of the double layer at negative potentials is different when CO₂ is present (probably due to the formation of CO_ad) and allow us to assign the main band in the spectra to CO adsorbed linearly on Au (CO_L), with a smaller band corresponding to bridge-bonded CO (CO_B). The CO bands show a large inhomogeneous broadening and are considerably broader than those typically observed in aqueous electrolytes. While both CO_L and CO_B can be observed in the CO adlayer generated by the electroreduction of CO₂, only a single, even broader band, at a frequency characteristic of CO_L is seen in CO-saturated solutions. We attribute this to the lower coverage of the adlayer formed upon reduction of CO₂, which leads to a lower degree of dipole–dipole coupling. Upon reversing the direction of the sweep in the CV, the intensity of the CO bands continues increasing for as long as a reduction current flows but starts decreasing at more positive potentials due to CO desorption from the surface