The effect of the alkyl chain length of the tetraalkylammonium cation on CO2 electroreduction in an aprotic medium

•The assessment of the effects of TAA+ cations on CO2 reduction is established.•The onset potential of CO2 reduction is dependent on the strength of ion pairing.•The peak current of CO2 reduction is determined by the quantity of the adsorbed TAA+ cation.

The effect of tetraalkylammonium cation (TAA+) chain length on CO2 electroreduction is investigated on an Ag electrode in a DMF solution. Linear sweep voltammetric (LSV) studies show that the onset potentials of CO2 reduction move to increasingly negative potentials upon increasing the alkyl chain length of the tetraalkylammonium cation of the supporting electrolyte. Density functional theory (DFT) computations indicate that the onset potential of CO2 reduction is dependent on the strength of ion pairing between TAA+ cation and the electrogenerated CO2.−. CO2 disturbance experiments reveal that the peak current of CO2 reduction is determined by the quantity of TAA+ cation adsorbed on the Ag surface.