Catalysts for carbon dioxide conversion

Patent metadata

Field	Value
Publication number	US-10370768-B2
Application number	US-201414392120-A
Country	US
Kind code	B2
Filing date	Jun 27, 2014
Priority date	Jun 27, 2013
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

The disclosure relates generally to improved methods for the reduction of carbon dioxide. The disclosure relates more specifically to catalytic methods for electrochemical reduction of carbon dioxide that can be operated at commercially viable voltages and at low overpotentials. The disclosure uses a transition metal dichalcogenide and helper catalyst in contact within the cell.

First claim

We claim:

1. A method of electrochemically reducing carbon dioxide in an electrochemical cell having a cathode comprising at least one transition metal dichalcogenide, an electrolyte in contact with the cathode, and an anode, the method comprising
contacting the carbon dioxide with the at least one transition metal dichalcogenide of the cathode of the electrochemical cell, the electrolyte comprising at least one helper catalyst, each helper catalyst comprising at least one positively charged nitrogen, sulfur, or phosphorus group and
applying a potential to the electrochemical cell sufficient to reduce the carbon dioxide, wherein the transition metal dichalcogenide is in nanoflake, nanosheet, or nanoribbon form, the transition metal dichalcogenide nanoflakes, nanosheets, or nanoribbons having an average size between about 1 nm and 400 nm.

2. A method of claim 1 , wherein the transition metal dichalcogenide is selected from the group consisting of TiX 2 , VX 2 , CrX 2 , ZrX 2 , NbX 2 , MoX 2 , HfX 2 , WX 2 , TaX 2 , TcX 2 , and ReX 2 , wherein X is independently S, Se, or Te.

3. A method of claim 1 , wherein the transition metal dichalcogenide is MoS 2 or MoSe 2 .

4. A method of claim 1 , wherein the transition metal dichalcogenide is in nanoflake form.

5. A method of claim 4 , wherein the transition metal dichalcogenide nanoflakes, nanosheets, or nanoribbons have an average size between about 50 nm and 400 nm.

6. A method of claim 1 , wherein the helper catalyst is an imidazolium, pyridinium, pyrrolidinium, phosphonium, ammonium, choline, sulfonium, prolinate, or methioninate salt.

7. A method of claim 1 , wherein the helper catalyst is an imidazolium salt, the imidazolium of the imidazolium salt having the formula:

wherein R 1 , R 2 , and R 3 are independently selected from the group consisting of hydrogen, linear aliphatic C 1 -C 6 group, branched aliphatic C 1 -C 6 group and cyclic aliphatic C 1 -C 6 group.

8. A method of claim 1 , wherein the helper catalyst is ethyl-3-methylimidazolium tetrafluoroborate.

9. A method of claim 1 , wherein the electrolyte is an aqueous solution.

10. A method of claim 9 , wherein the helper catalyst is present in the aqueous solution within the range from about 2 mol % to about 10 mol %.

11. A method of claim 1 , wherein the carbon dioxide is reduced to CO with a Faradaic efficiency of at least about 90%.

12. A method of claim 1 , wherein the applied potential is about −2 to about +2 V vs. reversible hydrogen electrode.

13. A method of claim 1 , wherein the reduction of carbon dioxide is initiated at overpotential of less than about 100 mV.

14. A method of claim 1 , wherein the reduction of carbon dioxide is at least about 90% Faradaic efficiency.

15. A method of claim 1 , wherein the transition metal dichalcogenide is vertically aligned.

16. A method of claim 1 , wherein the reduction of carbon dioxide is initiated at overpotential of less than about 100 mV and the carbon dioxide is reduced to CO with a Faradaic efficiency of at least about 90%.

17. A method of claim 1 , wherein the reduction of carbon dioxide is initiated at overpotential of less than about 100 mV and the reduction of carbon dioxide is at least about 90% Faradaic efficiency.

18. An electrochemical cell having a cathode comprising at least one transition metal dichalcogenide, wherein the transition metal dichalcogenide is in nanoflake, nanosheet, or nanoribbon form, the transition metal dichalcogenide nanoflakes, nanosheets, or nanoribbons having an average size between about 1 nm and 400 nm, and an electrolyte comprising at least one helper catalyst comprising at least one positively charged nitrogen, sulfur, or phosphorus group in contact with the transition metal dichalcogenide.

19. An electrochemical cell according to claim 18 , wherein the transition metal dichalcogenide is MoS 2 .

20. An electrochemical cell according to claim 18 , wherein the helper catalyst is present in an amount of about 4 mol % to about 10 mol %.

21. An electrochemical cell according to claim 18 , wherein the helper catalyst is ethyl-3-methylimidazolium salt tetrafluoroborate.

22. An electrochemical cell of claim 18 , wherein the helper catalyst is an imidazolium, pyridinium, pyrrolidinium, phosphonium, ammonium, choline, sulfonium, prolinate, or methioninate salt.

Assignees

• Univ Illinois

Inventors

• Salehi-Khojin Amin
• Asadi Mohammad
• Kumar Bijandra

Classifications

• C25B1/02 Primary

  Hydrogen or oxygen · CPC title

• C25B1/00

  Electrolytic production of inorganic compounds or non-metals · CPC title

• C25B3/04

  Chemistry & Metallurgy · mapped topic

• C25B11/0447 Primary

  Chemistry & Metallurgy · mapped topic

• C25B11/075 Primary

  consisting of a single catalytic element or catalytic compound · CPC title