Surface-specific vibrational spectroscopy of the graphene electrode/aqueous electrolyte interface

In view of the fundamental and technological importance of molecular details at the electrode/aqueous electrolyte interface, in this thesis, we apply surface-specific vibrational spectroscopy, heterodyne-detection sum-frequency generation (HD-SFG) spectroscopy, to the electrified graphene electrode surface, with the aim of probing the molecular details including the reorganization of the interfacial water and the interfacial hydrogen-bond network among the interfacial water, as well as the charging/discharging of the electrode under potentiostatically controlled conditions. Beyond the electrode/aqueous electrolyte interface, we experimentally unveil the nature of the nanoconfined water by using the HD-SFG spectroscopy technique which reveals that interfacial, rather than nanoconfinement effects, dominate the water structure until angstrom-level (<8 angstrom) confinement.