10.26165/JUELICH-DATA/0GQJFC Jovanovic, Svenhttps://orcid.org/0000-0002-1227-4936(IEK-9 Forschungszentrum Jülich)Jakes, Peterhttps://orcid.org/0000-0002-5187-4969(IEK-9 Forschungszentrum Jülich)Merz, Steffenhttps://orcid.org/0000-0002-2163-5027(IEK-9 Forschungszentrum Jülich)Daniel, Davis Thomashttps://orcid.org/0000-0001-7035-3416(IEK-9 Forschungszentrum Jülich, ITMC RWTH Aachen)Eichel, Rüdiger-A.https://orcid.org/0000-0002-0013-6325(IEK-9 Forschungszentrum Jülich, IPC RWTH Aachen)Granwehr, Josefhttps://orcid.org/0000-0002-9307-1101(IEK-9 Forschungszentrum Jülich, ITMC RWTH Aachen) Jülich DATA 2024 NMR raw data of 13C and 23Na experiments for the in operando CO2 electrolysis experiments in aqueous HCO3- electrolyte, as described in the publication. The in operando electrolysis experiments were divided into 3 stages: open circuit voltage (OCV), chronoamperometry (CA) at a constant voltage slightly below the electrolysis potential of -1.1 V vs. Ag/AgCl, and finally the chronopotentiometry (CP) at a constant current density of -10 µA/cm², where the electrolysis reaction took place. For each stage, 12 hours of spectra were recorded (Spectra recording). Afterwards, saturation recovery and CPMG experiments were performed for the determination of T1 and T2, respectively. In case of the 13C experiments, additional 1D exchange spectroscopy (EXSY) experiments were performed for the determination of the CO2/HCO3- exchange rate. 13C experiments were performed at two different magnetic fields (14.1 T and 9.4 T), 23Na at a single magnetic field (14.1 T). Jovanovic, Sven(IEK-9 Forschungszentrum Jülich)Granwehr, Josef(IEK-9 Forschungszentrum Jülich, ITMC RWTH Aachen)Jovanovic, Sven(IEK-9 Forschungszentrum Jülich)