Method for Converting Carbon Dioxide (CO2) into Syngas by an Electrolysis Reaction

Patent metadata

Field	Value
Publication number	US-2022064804-A1
Application number	US-201917415051-A
Country	US
Kind code	A1
Filing date	Dec 19, 2019
Priority date	Dec 19, 2018
Publication date	Mar 3, 2022
Grant date	—

Abstract

The present invention relates to a method for CO2 electroreduction to syngas, a mixture of carbon monoxide (CO) and hydrogen (H2), using a cathode comprising an electrically conductive support of which at least a part of the surface is covered by a metal deposit of zinc and of a second metal selected from copper, gold and mixtures thereof, and being preferably copper, said metal deposit comprising at least 1 wt % of one or several phases of an alloy of zinc and of the second metal.The present invention relates also to an electrode useful for performing this method, a process for preparing such an electrode and an electrolysis device comprising such an electrode.

First claim

1 . A method for converting carbon dioxide (CO 2 ) and water (H 2 O) into syngas, which is a mixture of carbon monoxide (CO) and hydrogen (H 2 ), comprising the following steps:
a) providing an electrolysis device comprising an anode and a cathode, wherein said cathode comprises an electrically conductive support of which at least a part of the surface is covered by a metal deposit of zinc and of a second metal selected from copper, gold and mixtures thereof, said metal deposit comprising at least 1 wt % of one or several phases of an alloy of zinc and of the second metal; b) exposing the cathode of said electrolysis device to a CO 2 -containing aqueous catholyte solution; c) applying an electrical current between the anode and the cathode in order to reduce the carbon dioxide into syngas.

2 . The method according to claim 1 , wherein the catholyte solution comprises a salt of hydrogen carbonate, which is optionally formed in situ by reaction of a hydroxide salt with CO 2 contained in the catholyte solution.

3 . The method according to claim 1 , wherein the metal deposit has a specific surface area of at least 0.1 m 2 ·g −1 ; and/or
wherein the metal deposit comprises at least 5 wt %, of one or several phases of an alloy of zinc and of the second metal; and/or
wherein the metal deposit has a thickness comprised between 1 μm and 250 μm; and/or
wherein the metal deposit has a porous structure with an average pore size of between 1 μm and 500 μm.

4 . The method according to claim 1 , wherein the weight ratio zinc/second metal in the metal deposit is comprised between 99/1 and 35/65.

5 . The method according to claim 1 , wherein the weight ratio zinc/second metal in the metal deposit is less than 35/65.

6 . The method according to claim 1 , wherein the obtained syngas is converted into saturated or unsaturated hydrocarbons, alcohols and/or aldehydes.

7 . An electrode comprising an electrically conductive support of which at least a part of the surface is covered by a metal deposit of zinc and of a second metal selected from copper, gold and mixtures thereof,
wherein said metal deposit comprises at least 1 wt % of one or several phases of an alloy of zinc and of the second metal and has a specific surface area greater than or equal to 0.1 m 2 ·g −1 .

8 . The electrode according to claim 7 , wherein the electrically conductive support comprises an electrically conductive material selected from a metal; a metal oxide; a metal sulphide; carbon; a semiconductor; and a mixture thereof.

9 . The electrode according to claim 7 , wherein the metal deposit has a specific surface area between 0.1 and 500 m 2 ·g −1 ; and
wherein the metal deposit comprises at least 5 wt % of one or several phases of an alloy of zinc and of the second metal.

10 . The electrode according to claim 7 , wherein the metal deposit has a thickness comprised between 1 μm and 250 μm; and/or
wherein the metal deposit has a porous structure with an average pore size of between 1 μm and 500 μm.

11 . The electrode according to claim 7 , wherein the weight ratio zinc/second metal in the metal deposit is comprised between 99/1 and 35/65.

12 . A process for preparing an electrode according to claim 7 comprising the following successive steps:
(i) providing an electrically conductive support;
(ii) immersing said electrically conductive support at least partially in an acidic aqueous solution containing ions of zinc and ions of the second metal; and
(iii) applying a current between the electrically conductive support and a second electrode, said current having a density comprised between −0.5 A·cm −2 and −0.1 A·cm −2 and being applied for a duration comprised between 30 s and 200 s.

13 . The process according to claim 12 , wherein the acidic aqueous solution containing ions of zinc and ions of the second metal is an acidic aqueous solution containing:
a salt of zinc; an oxidised zinc species; a Zn(OH) 3− -based salt; a Zn(OH) 4 2− -based salt; or a ZnO 2 2− -based salt; a salt of the second metal; an oxidised species of the second metal; or a mixture thereof.

14 . An electrolysis device comprising an electrode according to claim 7 .

15 . The electrolysis device according to claim 14 , coupled to a source of an electrical energy.

16 . The method according to claim 1 , wherein the second metal is copper.

17 . The method according to claim 1 , wherein the metal deposit comprises at least 20 wt % of one or several phases of an alloy of zinc and of the second metal.

18 . The method according to claim 1 , wherein the metal deposit has a specific surface area between 1 and 100 m 2 ·g −1 .

19 . The electrode according to claim 7 , wherein the second metal is copper.

20 . The electrode according to claim 7 , wherein the metal deposit comprises at least 20 wt % of one or several phases of an alloy of zinc and of the second metal.

Assignees

• Paris Sciences Et Lettres
• College France

Inventors

• Fontecave Marc
• Mougel Victor
• Tran Ngoc Huan
• Wakerley David
• Lamaison Sarah

Classifications

• Y02E60/50

  Fuel cells · CPC title

• C25C1/24

  Alloys obtained by cathodic reduction of all their ions · CPC title

• C25D1/08

  Perforated or foraminous objects, e.g. sieves (C25D1/10 takes precedence) · CPC title

• C25B3/26

  of carbon dioxide · CPC title

• C25B11/089

  Alloys · CPC title