Device and method for the electrochemical utilisation of carbon dioxide

1. An electrolyzer for electrochemical utilization of carbon dioxide, the electrolyzer comprising:

electrolysis cell defining an anode space and a cathode space;

an anode in the anode space;

a cathode in the cathode space;

a first cation-permeable membrane disposed between the anode space and the cathode space;

wherein the anode directly adjoins the first cation-permeable membrane;

a second anion-selective membrane disposed between the first cation-permeable membrane and the cathode; and

a spacer device disposed between at least part of the first cation-permeable membrane and at least part of the second anion-selective membrane

wherein the second anion-selective membrane directly adjoins the first cation-permeable membrane; and

the second anion-selective membrane directly adjoins the cathode.

2. The electrolyzer as claimed in claim 1 , further comprising a common contact area is disposed between the first cation-permeable membrane and the second anion-selective membrane; and

wherein the contact area is within a range from at least 80% up to 98% of a membrane area of the first or second membranes.

3. The electrolyzer as claimed in claim 1 , wherein the cathode and/or the second anion-selective membrane comprises relief openings for guiding carbon dioxide and water out of the spacer device into the cathode space.

4. The electrolyzer as claimed in claim 1 , wherein the spacer device comprises meshes, grids, or a porous structure.

5. The electrolyzer as claimed in claim 1 , further comprising an anion-conductive polymer disposed at least partly between the cathode and the second anion-selective membrane.

6. The electrolyzer as claimed in claim 1 , wherein the cathode comprises at least one of the elements selected from the group consisting of: silver, copper, lead, indium, tin, and zinc.

7. The electrolyzer as claimed in claim 1 , wherein the cathode comprises a gas diffusion electrode.

8. A method of operating an electrolyzer for electrochemical utilization of carbon dioxide, the method comprising:

decomposing a first amount of carbon dioxide to produce a product at a cathode disposed in a cathode space defined by an electrolysis cell;

transporting unconverted carbon dioxide as carbonate or hydrogencarbonate from the cathode through an anion-selective membrane disposed adjacent the cathode;

transporting hydrogen ions from an anode disposed in an anode space defined by the electrolysis cell through a cation-permeable membrane disposed between the anode space and the cathode space;

wherein the anode directly adjoins the cation-permeable membrane and the anion-selective membrane directly adjoins the cation-permeable membrane;

reacting the hydrogen ions and the carbonate or hydrogencarbonate to form a second amount of carbon dioxide and water between the cation-permeable membrane and the anion-selective membrane; and

releasing the second amount of carbon dioxide via flow channels or pores between the cation-permeable membrane and the anion-selective membrane.

9. The method as claimed in claim 8 , further comprising guiding the second amount of carbon dioxide back into the electrolyzer as a reactant.

10. The method as claimed in claim 8 , wherein the electrolyzer is operated with pure water.

11. The method as claimed in claim 8 , wherein the flow channels or pores are formed by means of a spacer device.

12. The method as claimed in claim 8 , further comprising forming at least one product selected from the group consisting of: carbon monoxide, ethylene, and formic acid.