Method and Device for the Electrochemical Utilization of Carbon Dioxide

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

an 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; and

a layer comprising an anion-selective polymer disposed between the first cation-permeable membrane and the cathode;

wherein the layer covers at least part of the cathode but not all of the cathode.

2 . The electrolyzer as claimed in claim 1 , wherein the layer covers a surface area of the first membrane within a range from 20% to 85%.

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

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

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

decomposing carbon dioxide at a cathode disposed in a cathode space of an electrolysis cell;

forming at least one of carbonate and hydrogencarbonate from unconverted carbon dioxide and hydroxide ions at the cathode;

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

wherein the anode directly adjoins the first cation-permeable membrane and a layer comprising an anion-selective polymer is disposed between the first cation-permeable membrane and the cathode;

reacting the hydrogen ions and the at least one of carbonate or hydrogencarbonate to produce carbon dioxide and water in a contact region of the layer and the first cation-permeable membrane; and

releasing the carbon dioxide through flow channels and/or pores in the layer.

6 . The method as claimed in claim 5 , wherein the electrolyzer is operated with pure water.

7 . The method as claimed in claim 5 , further comprising producing at least one of carbon monoxide, ethylene, or formic acid.

8 . (canceled)