Method for decomposing water into H2 and O2

Patent metadata

Field	Value
Publication number	US-11746429-B2
Application number	US-202218146128-A
Country	US
Kind code	B2
Filing date	Dec 23, 2022
Priority date	Oct 22, 2019
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

Abstract

A CoVOx composite electrode and method of making is described. The composite electrode comprises a substrate with an average 0.5-5 μm thick layer of CoVOx having pores with average diameters of 2-200 nm. The method of making the composite electrode involves contacting the substrate with an aerosol comprising a solvent, a cobalt complex, and a vanadium complex. The CoVOx composite electrode is capable of being used in an electrochemical cell for water oxidation.

First claim

The invention claimed is:

1. A method for decomposing water into H 2 and O 2 , comprising:
applying a potential of 0.5-2.0 V across electrodes immersed in an aqueous electrolyte solution in an electrochemical cell,
wherein the electrodes include a composite thin film electrode; and
a counter electrode; and
wherein the composite thin film electrode comprises a CoVOx layer having an average thickness of 500 nm-5 μm in contact with a substrate,
wherein the CoVOx layer comprises amorphous CoVOx having a Co:V molar ratio in a range of 1.0:1.2-1.5:1.0,
wherein the CoVOx layer has an O:Co molar ratio and/or an O:V molar ratio in a range of 4:1 to 9:1.

2. The method of claim 1 , wherein the CoVO x layer of the composite thin film electrode is porous with a pore size in a range of 2-10 nm.

3. The method of claim 1 , wherein the composite thin film electrode has an electrochemically active surface area in a range of 12-22 mF/cm 2 .

4. The method of claim 1 , wherein the CoVO x layer of the composite thin film electrode consists essentially of amorphous CoVO x .

5. The method of claim 1 , wherein the CoVO x layer of the composite thin film electrode has an O:Co molar ratio in a range of 4:1 to 9:1.

6. The method of claim 1 , wherein the composite thin film electrode has an overpotential in a range of 270-335 m V at a current density of 9-11 mA/cm 2 .

7. The method of claim 1 , wherein the composite thin film electrode has a current density of 1.0-10.0 mA/cm 2 when the electrodes are subjected to a bias potential of 1.45-1.55 V.

8. The method of claim 1 , wherein the aqueous electrolyte solution comprises water and an inorganic base having a concentration of 0.1-1.0 M.

9. The method of claim 1 , wherein the composite thin film electrode has a mass activity in range of 38-50 A/g at a potential of 350 mV.

10. The method of claim 1 , further comprising separately collecting H 2 -enriched gas and O 2 -enriched gas.

11. The method of claim 1 , wherein the substrate is a transparent conducting film.

12. The method of claim 11 , wherein substrate is a transparent conducting film selected from the group consisting of fluorine-doped tin oxide, indium tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium zinc oxide, indium zinc tin oxide, indium aluminum zinc oxide, indium gallium zinc oxide, indium gallium tin oxide, and antimony tin oxide.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Rehman Abdul
• Saeed Abbas Hakeem
• Ehsan Muhammad Ali

Classifications

• C25B11/073 Primary

  characterised by the electrocatalyst material · CPC title

• C01G31/006

  Compounds containing vanadium, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• C01G51/42

  containing alkali metals, e.g. LiCoO2 · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title