Broad topic: continuous and pulsed electrochemical reduction of CO2 using Cu-based gas diffusion electrodes in neutral electrolyte, operando characterisation using synchrotron radiation (wide-angle X-ray scattering), (bi)carbonate precipitation. Data is divided in subfolders named after the figure of the paper. Raw data, processed data, and Origin/PowerPoint files are all contained in the subfolders. Synchrotron raw data are linked to the experiment numbers MA5874 and INHC1776 at ESRF A subfolder corresponding to a sample contains: data from a potentiostat, gas chromatograms, recording of flow, pressure and temperature, tables of calculated Faradaic efficiency (FE), png image of the FE vs t, zipped raw files, and integrated synchrotron data. .json file was created using a yadg scheme (https://dgbowl.github.io/yadg/master/index.html), and data was processed by a dgpost scheme (https://dgbowl.github.io/dgpost/master/index.html) Synchrotron data are analysized using this python library https://github.com/EmpaEconversion/Twaxs