Fabrication of photoactive CaTiO3—TiO2 composite thin film electrodes via single step AACVD

Patent metadata

Field	Value
Publication number	US-11519086-B2
Application number	US-201916401793-A
Country	US
Kind code	B2
Filing date	May 2, 2019
Priority date	May 2, 2019
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A CaTiO 3 —TiO 2 composite electrode and method of making is described. The composite electrode comprises a substrate with an average 2-12 μm thick layer of CaTiO 3 —TiO 2 composite particles having average diameters of 0.2-2.2 μm. The method of making the composite electrode involves contacting the substrate with an aerosol comprising a solvent, a calcium complex, and a titanium complex. The CaTiO 3 —TiO 2 composite electrode is capable of being used in a photoelectrochemical cell for water splitting.

First claim

The invention claimed is:

1. A composite thin film electrode, comprising:
a CaTiO 3 —TiO 2 layer having an average thickness of 2-12 μm in contact with a substrate, the CaTiO 3 —TiO 2 layer comprising crystalline CaTiO 3 —TiO 2 particles having an average diameter of 0.2-2.2 μm,
wherein the CaTiO 3 —TiO 2 layer comprises 25-87 wt % CaTiO 3 and 13-75 wt % TiO 2 , each relative to a total weight of the CaTiO 3 —TiO 2 layer.

2. The composite thin film electrode of claim 1 , wherein the CaTiO 3 —TiO 2 layer comprises 80-85 wt % CaTiO 3 and 15-20 wt % TiO 2 , each relative to a total weight of the CaTiO 3 —TiO 2 layer.

3. The composite thin film electrode of claim 1 , wherein the crystalline CaTiO 3 —TiO 2 particles are substantially spherical.

4. The composite thin film electrode of claim 1 , wherein the TiO 2 is in anatase phase.

5. The composite thin film electrode of claim 1 , which has a direct band gap value in a range of 2.5-3.5 eV.

6. The composite thin film electrode of claim 1 , wherein the substrate is a transparent conducting film selected from the group consisting of ITO, FTO, AZO, GZO, IZO, IZTO, IAZO, IGZO, IGTO, and ATO.

7. The composite thin film electrode of claim 1 , wherein the substrate has a sheet resistance in a range of 1-40 Ωsq −1 .

8. A method of making the composite thin film electrode of claim 1 , the method comprising:
contacting an aerosol with the substrate to deposit a crystalline CaTiO 3 —TiO 2 composite layer on the substrate to form the composite thin film electrode,
wherein the aerosol comprises a carrier gas and a calcium complex and a titanium complex dissolved in a solvent, and
wherein the substrate has a temperature in a range of 400-650° C. during the contacting.

9. The method of claim 8 , wherein the calcium complex comprises trifluoroacetate ligands, acetate ligands, isopropanol ligands, and tetrahydrofuran ligands.

10. The method of claim 9 , wherein the calcium complex has a formula [Ca 2 (TFA) 3 (OAc))( i PrOH)(H 2 O)(THF) 3 ].

11. The method of claim 8 , wherein before the contacting, the aerosol consists essentially of the carrier gas, the calcium complex, the titanium complex, and the solvent.

12. The method of claim 8 , wherein the calcium complex and the solvent are present in the aerosol at a weight ratio of 1:1000-1:5.

13. The method of claim 8 , wherein the titanium complex and the solvent are present in the aerosol at a weight ratio of 1:10,000-1:5.

14. The method of claim 8 , wherein the aerosol is contacted with the substrate for a time period of 10-120 min.

15. The method of claim 8 , wherein during the contacting, the carrier gas has a flow rate in a range of 20-250 mL/min.

16. An electrochemical cell, comprising:
the composite thin film electrode of claim 1 ;
a counter electrode; and
an electrolyte solution in contact with both electrodes.

17. The electrochemical cell of claim 16 , wherein the electrolyte solution comprises water and an inorganic base having a concentration of 0.5-1.5 M.

18. The electrochemical cell of claim 16 , wherein the composite thin film electrode has a current density of 0.45-0.8 mA/cm 2 when the electrodes are subjected to a bias potential of 0.6-0.8 V and an illumination of 80-150 mW/cm 2 .

19. The electrochemical cell of claim 16 , wherein the composite thin film electrode has a charge transfer resistance in a range of 200-400Ω when subjected to an illumination of 80-150 mW/cm 2 .

20. A method of photocatalytic water splitting, comprising:
irradiating the electrochemical cell of claim 16 with sunlight.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Ehsan Muhammad Ali
• Rehman Abdul

Classifications

• C25B1/55

  Photoelectrolysis · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title

• Y02P20/133

  Renewable energy sources, e.g. sunlight · CPC title

• C25B11/052

  Electrodes comprising one or more electrocatalytic coatings on a substrate · CPC title

• C25B11/0773 Primary

  of the perovskite type · CPC title