Fig. 5: Understanding of the enhanced racemate stereoselectivity by CTAB modification.

Schematic of electrode–electrolyte interface and corresponding C–C coupling products: a Without CTAB. A water layer is formed at electrode–electrolyte interface. The interfacial water molecules show a strong solvation effect on the hydroxyl group of the ketyl radicals, which favors mesomer generation. b With CTAB. Interfacial water molecules are repelled away from electrode–electrolyte interface, which favors racemates generation. c In situ ATR-SEIRAS spectra at different potentials in the range of 1600–1800 cm⁻¹ and 3000–4000 cm⁻¹ over CP-CTAB electrode, in which the dash lines show the signals of interfacial water, and the light-blue arrow guides the blue shift in wavenumber at more negative potentials. Three representative interfacial water types are shown on the right, including hydrogen-bonded water with saturated coordination, hydrogen-bonded water with unsaturated coordination, and isolated water.