Method for electrochemical reduction of carbon dioxide

Patent metadata

Field	Value
Publication number	US-2018119296-A1
Application number	US-201615340686-A
Country	US
Kind code	A1
Filing date	Nov 1, 2016
Priority date	Nov 1, 2016
Publication date	May 3, 2018
Grant date	—

Abstract

A method of electrochemically reducing CO 2 to form at least one alcohol, preferably ethanol. The method includes (a) contacting an electrode system with an aqueous solution comprising at least one electrolyte and CO 2 , wherein the electrode system comprises a working electrode, a counter electrode, and a reference electrode, wherein the working electrode comprises a base electrode and a coating of a composite comprising graphene nanosheets and Cu 2 O nanoparticles disposed on a surface of the base electrode, and (b) applying a negative potential to the working electrode to reduce the CO 2 and form the at least one alcohol.

First claim

1 . A method of reducing CO 2 to form at least one alcohol, the method comprising:
(a) contacting an electrode system with an aqueous solution comprising at least one electrolyte and CO 2 , wherein the electrode system comprises a working electrode, a counter electrode, and a reference electrode, wherein the working electrode comprises a base electrode and a coating of a composite comprising graphene nanosheets and Cu 2 O nanoparticles disposed on a surface of the base electrode, and (b) applying a negative potential to the working electrode to reduce the CO 2 and form the at least one alcohol.

2 . The method of claim 1 , wherein the contacting is performed in a divided electrochemical cell comprising the counter electrode in a first cell compartment and the working electrode in a second cell compartment, wherein the aqueous solution is present in the first and the second cell compartment.

3 . The method of claim 1 , wherein the base electrode is selected from the group consisting of a metal base electrode, a carbon paper base electrode, a carbon cloth base electrode, a carbon felt base electrode, a graphite base electrode, a glassy carbon base electrode, and a conductive polymer base electrode.

4 . The method of claim 3 , wherein the base electrode is the metal base electrode, which comprises at least one metal selected from the group consisting of Cu, Al, Au, Ag, Zn, Ga, Hg, In, Cd, Ti, Pd, and Pt.

5 . The method of claim 1 , wherein the Cu 2 O nanoparticles are disposed on a surface of the graphene nanosheets in the composite.

6 . The method of claim 1 , wherein the Cu 2 O nanoparticles have an average particle size of 20-50 nm.

7 . The method of claim 6 , wherein a plurality of the Cu 2 O nanoparticles form a cubic cluster with the longest edge of 60-200 nm.

8 . The method of claim 7 , wherein the graphene nanosheets enclose the cubic cluster of the Cu 2 O nanoparticles in the composite.

9 . The method of claim 1 , wherein the composite has a weight ratio of the graphene nanosheets:the Cu 2 O nanoparticles in the range of 0.2-0.8.

10 . The method of claim 1 , wherein an amount of the coating of the composite disposed on the surface of the base electrode is 0.01-0.5 mg/cm 2 surface area of the base electrode.

11 . The method of claim 1 , wherein the at least one alcohol comprises ethanol.

12 . The method of claim 11 , wherein the reference electrode is an Ag/AgCl reference electrode, and wherein the negative potential is from −0.9 V to −1.3 V.

13 . The method of claim 12 , wherein the CO 2 is reduced to the ethanol at the working electrode with a faradaic efficiency of 5-10%.

14 . The method of claim 12 , wherein the working electrode has a current density of 0.5-3 mA/cm 2 .

15 . The method of claim 1 , wherein the aqueous solution is saturated with the CO 2 .

16 . An electrode system, comprising:
(a) a working electrode comprising a base electrode and a coating of a composite comprising graphene nanosheets and Cu 2 O nanoparticles disposed on a surface of the base electrode, wherein the composite has a weight ratio of the graphene nanosheets:the Cu 2 O nanoparticles in the range of 0.2-0.8, (b) a counter electrode, and (c) a reference electrode.

17 . The electrode system of claim 16 , wherein the Cu 2 O nanoparticles have an average particle size of 20-50 nm.

18 . The electrode system of claim 16 , wherein the Cu 2 O nanoparticles are disposed on a surface of the graphene nanosheets in the composite.

19 . The electrode system of claim 16 , wherein an amount of the coating of the composite disposed on the surface of the base electrode is 0.01-0.5 mg/cm 2 surface area of the base electrode.

20 . A method of making the working electrode of the electrode system of claim 16 , the method comprising:
(a) reacting graphene oxide with at least one Cu 2+ salt in the presence of at least one hydroxylamine, and/or at least one salt of hydroxylamine, and/or at least one substituted derivative of hydroxylamine and at least one surfactant in an alkaline aqueous solution to form a precipitate comprising the composite comprising graphene nanosheets and Cu 2 O nanoparticles, (b) suspending the precipitate in a dispersing media to form a dispersion comprising the composite, (c) depositing the dispersion on the surface of the base electrode to form a wet coating of the composite, and (d) drying the wet coating of the composite to form the coating of the composite comprising graphene nanosheets and Cu 2 O nanoparticles disposed on the surface of the base electrode.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Geioushy Ramadan A
• Khaled Mazen M

Classifications

• C25B9/06

  Chemistry & Metallurgy · mapped topic

• C25B11/0415

  Chemistry & Metallurgy · mapped topic

• C25B11/0405

  Chemistry & Metallurgy · mapped topic

• C25B3/04 Primary

  Chemistry & Metallurgy · mapped topic

• C25B11/0478

  Chemistry & Metallurgy · mapped topic