In this study, we employ vibrational sum frequency generation spectroscopy (VSFG) to probe the alignment of interfacial water in carbonate-containing electrolyte solutions at a gold electrode under applied potentials relevant for CO 2 R. We observe potential-dependent differences in the interfacial water spectrum, which are strongly influenced by the presence or absence of the carbonate anion as well as the electrolyte cation. With the aid of molecular dynamics simulations, these spectral differences are correlated with the effect of carbonate on the potential-dependent alignment of interfacial water and the formation of a sodium-carbonate ion complex, which is over-represented near the interface and significantly influences the spectral region of interest.