Fig. 2: Concept verification and electrochemical investigation of the system components.
a Schematic depiction of the electrochemical cell setup. Before the electrochemical reaction, either argon or CO2 gas was bubbled into the catholyte. The cell remained closed during the reaction. Gas and liquid products were analyzed using gas chromatography and NMR spectroscopy, respectively. b Selectivity of the cathode reaction among products using three different cathode materials. The left columns in each group indicate the selectivity of H2 among gas products from an Ar-saturated catholyte. The production of H2 suggests that halohydrin was electrochemically reduced to produce alkoxide. The right columns in each group show the average selectivity of EC by Faradaic efficiency in a CO2-saturated catholyte. The selectivity of ethylene carbonate was repeatedly measured three times, and the error bars indicate standard deviation. c Average EC iF.E. values with three different supporting electrolytes. To investigate the cationic effect, tetraalkylammonium salts with different carbon chain lengths and amidine salt were compared under same current densities of 10 mA/cm2. Each point was repeatedly measured three times, and the error bars indicate standard deviation. d Amount of ethylene oxide generated over time from the reaction between 2-chloroethanol and three different bases. To investigate the cationic effect on the alkoxide, combinations of the cation corresponding to the salt used in c and hydroxide anion were used as the base. The reaction was carried out in a 0.5 M chloride salt of the corresponding cation-deuterated methanol solution. e Average EC iF.E. values at three different current densities (2.5, 5, 10 mA/cm2). Each point was repeatedly measured three times, and the error bars indicate standard deviation. Source data for Fig. 2b, c–e are provided as a Source Data file.
