The Role of Surfactant in Electrocatalytic Carbon Dioxide Reduction in the Absence of Metal Cations.

Carbon dioxide electroreduction does not occur on Au when metal cations are absent from the electrode surfaces. Here we show that the electroreduction can be enabled without metal cations, albeit with low efficiency, by the presence of cationic surfactants on Au. The findings demonstrate that in addition to possibly stabilizing CO₂ reduction intermediates the presence of surfactants plays a role in suppressing the competing reactions. At potentials negative of a critical potential, a cationic surfactant adsorbs onto the electrode surface, displacing interfacial water molecules, hampering the access of proton donors to the electrode surface and inhibiting hydrogen evolution during electrolysis.