Electrochemical cell containing a graphene coated electrode

Patent metadata

Field	Value
Publication number	US-2016251765-A1
Application number	US-201415031458-A
Country	US
Kind code	A1
Filing date	Oct 27, 2014
Priority date	Oct 25, 2013
Publication date	Sep 1, 2016
Grant date	—

Abstract

An electrochemical cell 10 is provided that includes first and second electrodes 13, 15, an electrolyte medium 17 in electrolytic communication with the first and second electrodes 13, 15, a chemical substance capable of undergoing an electrochemical reaction, and a voltage source 19 in electrolytic communication with the first and second electrodes 13, 15. The first electrode 13 includes a layer of an active catalyst material 25, and graphene coating 27 at least partially covering the layer of the active catalyst material 25. Methods for making and using the graphene coated electrode are further provided.

First claim

1 . An electrochemical cell comprising:
a first electrode comprising a layer of an active catalyst material, and graphene coating at least partially covering the layer of the active catalyst material; a second electrode comprising a conductor; an electrolyte medium in electrolytic communication with the first and second electrodes; a chemical substance capable of undergoing an electrochemical reaction; and a voltage source in electrolytic communication with the first and second electrodes.

2 . The electrochemical cell of claim 1 , wherein the first electrode further comprises a support material selected from the group consisting of platinum mesh, platinum foil, gold mesh, gold foil, tantalum mesh, tantalum foil, platinum sponge, iridium sponge, a carbon support integrated with a conductive metal, Ni foil, Ti foil, graphite, carbon fiber, carbon paper, glassy carbon, carbon nanofiber, and carbon nanotube.

3 . (canceled)

4 . The electrochemical cell of claim 1 , wherein the active catalyst material comprises a member selected from the group consisting of platinum, iridium, rhodium, rubidium, ruthenium, rhenium, palladium, gold, silver, nickel, iron, cobalt, copper, zinc, chromium, tantalum, gallium, cadmium, indium, thallium, tin, lead, bismuth, silver, mercury, niobium, vanadium, manganese, aluminum, arsenic, selenium, antimony, titanium, tungsten, Raney metal, carbon steel, stainless steel, graphite, and mixtures and alloys thereof.

5 . (canceled)

6 . The electrochemical cell of claim 1 , wherein the graphene coating comprises a graphene film prepared by chemical vapor deposition of electrolyzed coal.

7 . (canceled)

8 . A method for making the first electrode of the electrochemical cell of claim 1 , said method comprising:
preparing a graphene coating; and covering at least a portion of the active catalyst material with the graphene coating.

9 . The method of claim 8 , wherein preparing the graphene coating comprises:
heating electrolyzed coal to a temperature effective to form graphite in the presence of a flowing stream of reductant gas, wherein the stream of reductant gas deposits graphene onto a surface of a copper substrate; and dissolving the copper substrate.

10 . The method of claim 8 , wherein a surface of the active catalyst material is abraded prior to covering with the graphene coating.

11 . A method of performing an electrochemical reaction with the electrochemical cell of claim 1 , said method comprising:
contacting the first electrode with the chemical substance in the presence of the electrolyte medium; and applying a voltage difference between the first and second electrodes effective to carry out the electrochemical reaction.

12 . (canceled)

13 . The method of claim 1 , wherein the electrolyte medium comprises a hydroxide concentration of about 0.1 M to about 5 M.

14 . The method of claim 11 , wherein the electrolyte medium comprises a hydroxide salt, a carbonate salt, a bicarbonate salt, or combinations thereof.

15 . (canceled)

16 . The method of claim 11 , wherein the electrolyte medium comprises a pH-neutral buffer solution.

17 . The method of claim 11 , wherein the chemical substance is selected from the group consisting of an alcohol, urea, ammonia, and combinations thereof.

18 . A method for producing ammonia by an electrolytic hydrolysis of urea, comprising:
applying a voltage difference to an electrolytic cell comprising:
a first electrode comprising a layer of an active catalyst material, and graphene coating at least partially covering the layer of the active catalyst material;
a second electrode comprising a conductor;
an electrolyte medium in electrolytic communication with the first and second electrodes;
urea; and
a voltage source in electrolytic communication with the first and second electrodes, wherein the voltage difference is applied across the first and second electrodes and is sufficient to effect the electrolytic hydrolysis of urea to produce ammonia.

19 . The method of claim 18 , wherein the electrolyte medium comprises a carbonate salt and has a pH in a range from about 10 to about 7.

20 . An electrode comprising:
a layer of an active catalyst material, and a graphene coating at least partially covering the layer of the active catalyst material.

21 . The electrode of claim 20 , wherein the graphene coating is prepared by a process, comprising heating electrolyzed coal to a temperature effective to form graphene in the presence of a flowing stream of reductant gas, wherein the stream of reductant gas deposits graphene onto a surface of a substrate.

22 . The electrode of claim 21 , wherein the substrate comprises the layer of the active catalyst material.

23 . The electrode of claim 21 , wherein the substrate comprises copper, and wherein the process further comprises dissolving the copper substrate, and lifting the graphene coating onto the active catalyst material.

24 . The electrode of claim 20 , wherein the active catalyst material comprises a member selected from the group consisting of platinum, iridium, rhodium, rubidium, ruthenium, rhenium, palladium, gold, silver, nickel, iron, cobalt, copper, zinc, chromium, tantalum, gallium, cadmium, indium, thallium, tin, lead, bismuth, silver, mercury, niobium, vanadium, manganese, aluminum, arsenic, selenium, antimony, titanium, tungsten, Raney metal, carbon steel, stainless steel, graphite, and mixtures and alloys thereof.

25 . (canceled)

26 . The electrode of claim 20 , wherein the active catalyst material comprises a metal oxyhydroxide.

Assignees

• Univ Ohio

Inventors

• Botte Gerardine G

Classifications

• C01C1/086

  from urea · CPC title

• C01B31/0453

  Chemistry & Metallurgy · mapped topic

• C25B11/0478 Primary

  Chemistry & Metallurgy · mapped topic

• C25B1/00 Primary

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

• C25B9/06

  Chemistry & Metallurgy · mapped topic