The Importance of Acid–Base Equilibria in Bicarbonate Electrolytes for CO₂ Electrochemical Reduction and CO Reoxidation Studied on Au(hkl) Electrodes

and the concentration of the bicarbonate) and voltammetric parameters. In this way, we identify different regimes of surface pH and bicarbonate speciation, as a function of the current and electrolyte conditions. We reveal the importance of the acid-base bicarbonate/carbonate couple, not only as a buffering equilibrium but also as species involved in the electrochemical reactions under study.