Gallium oxynitride-zinc oxide photoelectrode for solar water splitting

Patent metadata

Field	Value
Publication number	US-11427919-B2
Application number	US-201816131236-A
Country	US
Kind code	B2
Filing date	Sep 14, 2018
Priority date	Sep 14, 2018
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A GaON/ZnO photoelectrode involving a nanoarchitectured photocatalytic material deposited onto a surface of a conducting substrate, and the nanoarchitectured photocatalytic material containing gallium oxynitride nanoparticles interspersed in zinc oxide nanoparticles, as well as methods of preparing the GaON/ZnO photoelectrode. A method of using the GaON/ZnO photoelectrode for solar water electrolysis is also provided.

First claim

The invention claimed is:

1. A GaON/ZnO photoelectrode, comprising:
a metal oxide conducting substrate; and
a nanoarchitectured photocatalytic material deposited onto a surface of the metal oxide conducting substrate;
wherein the nanoarchitectured photocatalytic material comprises:
zinc oxide nanoparticles; and
gallium oxynitride nanoparticles interspersed in the zinc oxide nanoparticles;

wherein the zinc oxide nanoparticles form a framework;
wherein the gallium oxynitride nanoparticles are interpenetrated in the framework; and
the gallium oxynitride nanoparticles are uniformly distributed in the framework.

2. The GaON/ZnO photoelectrode of claim 1 , wherein the zinc oxide nanoparticles are in the form of nanorods.

3. The GaON/ZnO photoelectrode of claim 1 , wherein the gallium oxynitride nanoparticles are in the form of nanosheets.

4. The GaON/ZnO photoelectrode of claim 2 , wherein the nanorods have an average diameter of 20-100 nm and an average length of 500-2,000 nm.

5. The GaON/ZnO photoelectrode of claim 3 , wherein the nanosheets have an average thickness of 5-50 nm and an average length of 200-1,500 nm.

6. The GaON/ZnO photoelectrode of claim 1 , wherein a weight ratio of the zinc oxide nanoparticles to the gallium oxynitride nanoparticles is in a range of 4:1 to 100:1.

7. The GaON/ZnO photoelectrode of claim 1 , wherein the metal oxide conducting substrate is fluorine doped tin oxide substrate.

8. The GaON/ZnO photoelectrode of claim 1 , which has an ultraviolet visible absorption with an absorption edge of 410-520 nm.

9. The GaON/ZnO photoelectrode of claim 1 , which has a band gap energy of 2.2-2.7 eV.

10. A photoelectrochemical cell, comprising:
the GaON/ZnO photoelectrode of claim 1 ;
a counter electrode; and
an electrolyte solution comprising water and an inorganic salt in contact with both the GaON/ZnO photoelectrode and the counter electrode.

11. The photoelectrochemical cell of claim 10 , wherein the electrolyte solution has an inorganic salt concentration of 0.05-1 M.

12. The photoelectrochemical cell of claim 10 , wherein the GaON/ZnO photoelectrode has a photo-current density in a range from 0.01-1.5 mA/cm 2 when the photoelectrochemical cell is subjected to a potential of 0.1 to 1.5 V under visible light irradiation.

13. The photoelectrochemical cell of claim 10 , further comprising a reference electrode.

14. A method of splitting water into hydrogen gas and oxygen gas, the method comprising:
subjecting the photoelectrochemical cell of claim 10 to a potential of 0.5 to 2.0 V; and
concurrently irradiating the photoelectrochemical cell with visible light, thereby forming hydrogen gas and oxygen gas.

15. A method of producing the GaON/ZnO photoelectrode of claim 1 , the method comprising:
mixing the zinc oxide nanoparticles and the gallium oxynitride nanoparticles in a solvent to form a mixture;
sonicating the mixture to form a dispersed mixture;
depositing the dispersed mixture onto a surface of the metal oxide conducting substrate to form a deposited substrate; and
heating the deposited substrate at a temperature of 70-150° C. for 0.5-4 hours.

16. The method of claim 15 , wherein a weight ratio of the zinc oxide nanoparticles to the gallium oxynitride nanoparticles is in a range of 4:1 to 100:1.

17. The method of claim 15 , wherein the solvent is water.

18. The method of claim 15 , wherein the depositing is performed at a temperature of 50-120° C.

19. The method of claim 15 , wherein the depositing is performed at a pressure of 100-300 kPa.

20. The method of claim 15 , wherein the heating is followed by cooling to a temperature ranging from 5-40° C. thereby forming the GaON/ZnO photoelectrode.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Qurashi Ahsanulhaq
• Khan Ibrahim

Classifications

• C01P2004/16

  Nanowires or nanorods, i.e. solid nanofibres with two nearly equal dimensions between 1-100 nanometer · CPC title

• C25B11/091 Primary

  consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds · CPC title

• C25B11/00

  Electrodes; Manufacture thereof not otherwise provided for · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C01B21/0821 Primary

  Oxynitrides of metals, boron or silicon · CPC title