Electrolysis cell, electrolyzer and method for reducing CO2

An electrolysis cell for an electrochemical reaction of CO2 on an industrial scale of more than 0.1 kg CO2/(h*m2), comprising:

• at least a cathode half shell having a rear wall;
• a gas space comprising carbon dioxide gas;
• a cathode with a vertical main extension of at least 30 cm:
• an anode half shell;
• a separator arranged between the anode half shell and the cathode half shell for separating anode space and cathode space;
• and
• electric power leads;
• wherein a distance from the cathode to the rear wall of the cathode half shell is not more than 5 cm to achieve a velocity of the carbon dioxide gas in the gas space close to a rear side of the cathode from 0.001 to 15 m/s,
• wherein the gas space is connected to a first gas feed conduit for carbon dioxide gas and to a first gas discharge conduit for gaseous reaction products, and having a catholyte, a catholyte inlet and a catholyte outlet,
• wherein the anode half shell is provided with at least a second gas discharge conduit for an anode reaction product, an anolyte inlet, anolyte and an anolyte outlet and an anode,
• wherein the electric power leads are for connecting the anode and the cathode to a DC voltage source,
• wherein the cathode is configured as a gas diffusion electrode for reacting carbon dioxide gas and the cathode, and
• wherein the anode and the separator are arranged vertically in their main extension and a gap for passage of the catholyte according to the principle of a falling liquid film is arranged between the separator and the cathode.