Proton-coupled electron transfer reactions at an electrochemical interface, such as electrosorption of a solvated proton (the Volmer reaction), are the key elementary steps in many electrocatalytic processes. Their characterization is challenging mainly because of the presence of an electric double layer (EDL). Using operando vibrational spectroscopy accompanied by theoretical analysis, Sarkar et al. identified the main stages of the Volmer reaction corresponding to proton discharge from tertiary ammonium with a benzonitrile vibrational tag to a silver electrode surface, and revealed the role of the EDL in this process. They anticipate that their mechanistic insights are general and may be useful in the rational design of materials for electrochemical energy storage and conversion.
J. Am. Chem. Soc. 143, 8381 (2021).