Fig. 3: Altering interfacial structure at Au surface in aqueous electrolytes.

a–c The potential-dependent OH stretching features of in situ SEIRAS spectra at pH13 in a H₂-saturated aqueous solution of 0.1 M of LiOH, KOH, and CsOH, respectively, where the reference spectrum was taken at 1.1 V_RHE. Full spectra before and after subtracting by reference spectrum (at 1.1 V_RHE) are available in Supplementary Fig. 8. d The deconvolution of the OH stretching peak of spectra acquired at −0.6 V_RHE, where OH stretching peak was deconvoluted into three components: 1) 3600 cm⁻¹ with width=160 cm⁻¹ (isolated water), 2) 3450 cm⁻¹ with width=260 cm⁻¹ (asymmetrically H-bonded water), and 3) 3240 cm⁻¹ with width=250 cm⁻¹ (symmetrically H-bonded water). The deconvolution of OH stretching peak at other potentials is shown in Supplementary Fig. 12. e–g The potential- and cation-dependence of the relative fraction of peaks at 3600 cm⁻¹, 3450 cm⁻¹, and 3240 cm⁻¹. h A schematic showing that Li⁺ promotes symmetric H-bonded water at the interface while Cs⁺ tends to form isolated water molecules at the Au surface.