Tailoring the Interfacial Water Structure by Electrolyte Engineering for Selective Electrocatalytic Reduction of Carbon Dioxide

Nandita Mohandas, Tharangattu Narayanan, Angel Cuesta Ciscar* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Engineering aqueous electrolytes with low amounts of additives to achieve a tunable CO2 reduction product is an underexplored territory in electrocatalysis. Here, we show the enhancement of the Faradaic efficiency (FE) of CO2 reduction to CO on unmodified polycrystalline gold from ∼67 to ∼94% by the addition of up to 15 mol % of N,N-dimethylformamide (DMF) to an aqueous electrolyte. The role of electrolyte structure modification near the electrode–electrolyte interface was studied using in situ surface-enhanced infrared absorption spectroscopy in attenuated total reflection mode (ATR-SEIRAS). In addition to the expected detection of the adsorbed CO (COad) intermediate present on the Au surface, in both the linearly bonded and bridge-bonded forms, we observed changes in the structure of interfacial water induced by the addition of DMF. The changes in the water stretching band and the DMF carbonyl band indicate an increase in the strongly hydrogen-bonded DMF–water pairs with increasingly negative potential near the interface in the presence of DMF. We hold this interfacial water structure modification by DMF responsible for increasing the CO2RR FE and decreasing the competing hydrogen evolution reaction (HER). Furthermore, the suppression of the HER is observed in other electrolytes and also when platinum was used as an electrode and hence can be a potential method for increasing the product selectivity of complex electrocatalytic reactions
Original languageEnglish
Pages (from-to)8384−8393
Number of pages10
JournalACS Catalysis
Early online date9 Jun 2023
Publication statusPublished - 9 Jun 2023

Bibliographical note

Open Access via the ACS Agreement
Department of Atomic Energy, Government of India - RTI4007
N.M. and T.N.N. acknowledge the support of the Department of Atomic Energy, Government of India, under Project Identification No. RTI4007. N.M. acknowledges the funding support of Infosys Foundation through Infosys� TIFR Leading Edge Travel Grant. N.M. acknowledges Dr. Anku Guha and Dr. Andrew Burley for useful discussions. A.C. acknowledges the continued support of the University of Aberdeen.


  • electrochemical CO2 reduction
  • electrolyte engineering
  • hydrogen-bonding network
  • DMF
  • CO2RR product selectivity
  • HER suppresion
  • spectro-electrochemistry


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