PHOTO ELECTRODES

• US 20120010068A1
• Filed: 11/14/2008
• Published: 01/12/2012
• Est. Priority Date: 11/16/2007
• Status: Active Grant

• Current Assignee: 579453 Ontario Incorporated
• Original Assignee: Aqua Diagnostic Pty Limited Level 1
• Inventors: Zhao, Huijun, Imisides, Mark, Zhang, Shanqing
• Granted Patent: US 8,673,810 B2
• Time in Patent Office: Days
• US Class Current: 502/1
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/0018 Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
• CPC Class Codes: B01J 37/10 in the presence of water, e.g. steam
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01G 23/053 Producing by wet processes, e.g. hydrolysing titanium salts
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2217/948 Layers comprising indium tin oxide [ITO]
• CPC Class Codes: C03C 2218/11 from solutions or suspensions
• CPC Class Codes: C03C 2218/32 After-treatment
• CPC Class Codes: H01G 9/2031 comprising titanium oxide, e.g. TiO2 H01G9/2036 takes precedence
• CPC Class Codes: Y02E 10/542 Dye sensitized solar cells

Abstract

Methods of fabricating nano particulate Titanium dioxide photocatalysts onto a conducting substrate are disclosed. The methods include hydrothermal fabrications with heat treatment steps to increase the crystallinity and photoactivity of the titanium dioxide layers.

Claims

1. A method of forming a titanium dioxide photocatalyst in which,

a) titanium dioxide colloidal particles are formed in solution and then subjected to dialysis while maintaining the pH below 4,

b) the dialysed solution is the subjected to a hydrothermal treatment,

c) the colloid from step b) is then coated on a substrate of conducting glass and dried,

d) the coated substrate from step c) is calcined from 700 C to 800 C.

2. A method of forming a titanium dioxide photocatalyst as claimed in claim 1 in which the colloid from step b) has an average particle size in the range of 8 to 35 nm.

3. A method as claimed in claim 1 in which the dialysis is concluded at a pH of about 3.8 and the calcinations is at about 700 C for about two hours.

4. A method of forming a titanium dioxide photocatalyst as claimed in claim 1 in which the substrate is conducting glass which is sequentially washed with detergent, chromic acid and alcohol.

5. A method as claimed in claim 4 in which the titanium dioxide layer has a thickness of from 0.5 to 20 microns.

6. A photo electrode produced by the method of as claimed in claim 1.

7. A method of fabricating a titanium dioxide photocatalyst in which,

a) a template formation solution of a polymer and a titanium compound is coated onto a conducting substrate,

b) the coated substrate is subjected to hydrothermal treatment at a temperature of from 5O C to 130 C for between 5 and 170 hours,

c) the treated substrate from step b) is then heated at between 450 C and 650 C for 0.5 to 5 hours.

8. A method of fabricating a titanium dioxide photocatalyst as claimed in claim 7 in which the titanium dioxide layer is composed of ordered hexagonal structures sized from 0.5 to 20 microns.

9. A method as claimed in claim 7 in which the template solution includes mono carboxy terminated polystyrene and titanium tetraisopropoxide.

10. A method as claimed in claim 9 in which the hydrothermal treatment is carried out at about 100 C for about 70 hours.

11. A method as claimed in claim 10 in which the heat treatment is carried out at about 550 C for about 2 hours.

12. A photo electrode produced by the method as claimed in claim 7.