Co2 electroreduction to multi-carbon products in acidic conditions coupled with co2 regeneration from carbonate

Patent metadata

Field	Value
Publication number	US-2026009143-A1
Application number	US-202319118631-A
Country	US
Kind code	A1
Filing date	Sep 26, 2023
Priority date	Oct 13, 2022
Publication date	Jan 8, 2026
Grant date	—

Abstract

The disclosure relates to a process for electrolysing carbon dioxide using a gas-fed flow cell comprising a gas diffusion electrode comprising a metal-based catalyst, wherein the catholyte flow is an acidic catholyte flow comprising one or more alkali metal cations, wherein the gas-fed flow cell comprises a bipolar membrane and wherein the acidic catholyte has a pH of at most 5.5 and the catholyte pH is less than the anolyte pH.

First claim

1 . Process for electrolysing carbon dioxide, said process is characterized in that it comprising the following steps:
a) providing a system comprising a gas-fed flow cell comprising a gas chamber with a gas inlet, a gas outlet, a catholyte chamber, and a gas diffusion electrode comprising a metal-based catalyst, wherein the gas diffusion electrode is placed between the gas chamber and the catholyte chamber; b) providing a catholyte flow and an anolyte flow into said gas-fed flow cell; c) activating said gas-fed flow cell under operating conditions; d) providing a gas input flow comprising carbon dioxide using the gas inlet of the gas chamber to produce a direct gas stream exiting from the gas outlet of the gas chamber and a liquid catholyte output flow from the catholyte chamber comprising products, wherein said liquid catholyte output flow is degassing in a catholyte reservoir to produce an indirect gas stream exiting from a gas outlet of the catholyte reservoir;
wherein the catholyte flow is an acidic catholyte flow comprising one or more alkali metal cations and in that the gas-fed flow cell comprises a bipolar membrane includes a cation-exchange layer in contact with the catholyte and an anion-exchange layer in contact with the anolyte; wherein the cation-exchange layer provides protons to the catholyte and the anion exchange layer provides hydroxide ions to the anolyte; in that the acidic catholyte has a pH of at most 5.5 and in that the catholyte pH is less than the anolyte pH.

2 . The process according to claim 1 is characterized in that the indirect gas stream exiting from the catholyte reservoir comprises carbon dioxide, and in that the process further comprises a step e) of recovering the indirect gas stream exiting from the catholyte reservoir and recycling said indirect gas stream into the gas input flow comprising carbon dioxide of step d).

3 . The process according to claim 1 is characterized in that the gas input flow provided in step (d) has a flow rate ranging from 0.5 to 10 mL/min; preferably from 0.9 to 2.8 mL/min or from 1.0 to 2.5 mL/min.

4 . The process according to claim 1 is characterized in that the acidic catholyte has a pH ranging from 0.5 to 5.4; preferably from 1.0 to 4.0.

5 . The process according to claim 1 is characterized in that the anolyte has a pH ranging from 7 to 15; preferably from 10 to 14.

6 . The process according to claim 1 is characterized in that the acidic catholyte comprises one or more acids at a concentration ranging from 0.01 to 1.0 M and one or more alkali metal cation donors at a concentration ranging from 1.0 to 5.0 M.

7 . The process according to claim 6 is characterized in that the one or more alkali metal cations are one or more selected from Cs + , K + , Li + , and Na + ; preferably the one or more alkali metal cations are or comprise K + .

8 . The process according to claim 1 is characterized in that the acidic catholyte comprises one or more alkali metal cation donors selected from caesium chloride, caesium iodide, caesium sulfate, caesium phosphate, caesium hydroxide, potassium chloride, potassium phosphate monobasic, potassium sulfate, potassium iodide, potassium hydroxide, lithium chloride, lithium iodide, lithium sulfate, lithium phosphate, lithium hydroxide, sodium chloride, sodium sulphate, sodium iodide, sodium phosphate and sodium hydroxide; preferably selected from potassium chloride, potassium phosphate monobasic, potassium sulfate, potassium iodide, and potassium hydroxide; more preferably the one or more alkali metal cation donors are or comprise potassium chloride.

9 . The process according to claim 8 is characterized in that the one or more alkali metal cation donors at a concentration ranging from 0.5 to 5.0 M; preferably ranging from 2.0 to 4.0 M.

10 . The process according to claim 1 is characterized in that the acidic catholyte comprises one or more acids selected from hydrochloric acid, sulfuric acid, hydrobromic acid, hydriodic acid, perchloric acid, and chloric acid; preferably sulfuric acid.

11 . The process according to claim 10 is characterized in that the one or more acids are present at a concentration ranging from 0.01 to 1.0 M; preferably, from 0.02 to 0.5 M; more preferably ranging from 0.03 to 0.2 M.

12 . The process according to claim 1 is characterized in that the metal of the metal-based catalyst is selected from copper, silver and any mixture thereof; and/or the metal-based catalyst is or comprises copper oxide nanoparticles and the process comprises a catalyst activation step to reduce copper oxide to metallic copper.

13 . The process according to claim 1 is characterized in that the operating conditions at which the flow cell is operated in step c) comprise current density ranging from −100 mA.cm 2 to −1.5 A.cm 2 ; preferably from −150 mA.cm 2 to −800 mA.cm 2 .

14 . A system ( 1 ) suitable to perform the process for electrolysing carbon dioxide according to claim 1 , the system comprising a gas-fed flow cell ( 3 ) comprising a gas chamber ( 5 ), a catholyte chamber ( 7 ) and an anolyte chamber ( 9 ), wherein said gas chamber ( 5 ) is separated from the catholyte chamber ( 7 ) by a gas diffusion electrode ( 17 ), said gas diffusion electrode ( 17 ) having a gas diffusion membrane being comprised within said gas chamber, wherein said catholyte chamber ( 7 ) and said anolyte chamber ( 9 ) comprise respectively a cathode and an anode, and wherein the system ( 1 ) further comprises catholyte ( 23 ) and anolyte ( 25 ) and means ( 27 ; 29 ) to flow the catholyte ( 23 ) and the anolyte ( 25 ) within respectively said catholyte chamber ( 7 ) and said anolyte chamber ( 9 );
wherein the system is characterized in that the catholyte flow is an acidic catholyte flow comprising one or more alkali metal cations and in that the gas-fed flow cell comprises a bipolar membrane ( 19 ) that includes a cation-exchange layer in contact with the catholyte and an anion-exchange layer in contact with the anolyte; wherein the cation-exchange layer provides protons to the catholyte and the anion exchange layer provides hydroxide ions to the anolyte; in that the acidic catholyte has a pH of at most 5.5 and in that the catholyte pH is less than the anolyte pH; and wherein the system ( 1 ) further comprises a catholyte reservoir to receive and degas the liquid catholyte output flow exiting the catholyte chamber, and with preference, means ( 31 ) to recover an indirect gas stream exiting the gas outlet ( 33 ) of the catholyte reservoir, and means ( 35 ) to recycle the said indirect gas stream back into the gas chamber ( 5 ).

15 . (canceled)

Assignees

• Totalenergies Onetech
• College France

Inventors

• Schreiber Moritz Wilhelm
• Perazio Alessandro
• Fontecave Marc
• Creissen Charles E

Classifications

• C25B15/08

  Supplying or removing reactants or electrolytes; Regeneration of electrolytes · CPC title

• C25B9/19

  with diaphragms · CPC title

• C25B3/03

  Acyclic or carbocyclic hydrocarbons · CPC title

• C25B3/07

  Oxygen containing compounds · CPC title

• C25B3/26 Primary

  of carbon dioxide · CPC title