Effects of the Electrolyte on Electrochemical Reduction of CO2 on Sn Electrode

Abstract

This paper discusses the effects of the electrolyte on the selectivity and activity of electrochemical reduction of CO2 on Sn electrode including changes in cation, anion and concentration. The production of formate was quantitatively monitored by 1H NMR spectroscopy. Both the anion SO42- and the cation Na+ favor higher faradaic efficiency and energy efficiency while HCO3- and Cs+ enable high rate production of formate. The faradaic efficiency is as high as 69-76% for 0.5 M Na2SO4 in the potential range from -1.5 to -1.7 V vs. SCE. 0.5 M KHCO3 is an optimal electrolyte for high production rate of formate which could reach over 3.8 μmol min-1 cm-2 at potentials of -2.0 V vs. SCE while keeping faradaic efficiency of ~63%.