C AND N-DOPED TITANIUMOXIDE-BASED PHOTOCATALYTIC AND SELF-CLEANING THIN FILMS AND THE PROCESS FOR PRODUCTION THEREOF

• US 20060247125A1
• Filed: 04/26/2006
• Published: 11/02/2006
• Est. Priority Date: 04/27/2005
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology
• Original Assignee: Korea Advanced Institute of Science and Technology
• Inventors: Choi, Won-Kook, Lee, Kyung-Ju, Jung, Yeon-Sik, Kang, Dong-Heon
• Granted Patent: US 7,544,631 B2
• Time in Patent Office: Days
• US Class Current: 502/175
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 27/22 Carbides
• CPC Class Codes: B01J 27/24 Nitrogen compounds
• CPC Class Codes: B01J 35/004 Photocatalysts
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/34 Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
• CPC Class Codes: B01J 37/347 Ionic or cathodic spraying; Electric discharge

Abstract

The present invention provides for titanium oxide-based photocatalysts having a general formula of TiO_2-X-δC_XN_δ and self-cleaning materials that are prepared by substituting O of pure TiO2 with C and N. A preparation method comprising a process for forming thin films of TiO_2-X-δC_XN_δ by using gases such as Ar, N₂, CO₂, CO and O are used for reactive sputtering, and a process of heat treating at around 500° C., thereby crystallizing, is provided. The titanium oxide-based photocatalysts having a general formula of TiO_2-X-δC_XN_δ and self-cleaning materials according to the present invention have a smaller optical bandgap compared to pure titanium oxides, and therefore, the photocatalysts can be activated under the visible light range. In addition, they comprise only pure anatase crystallization phase, and since the crystallized particles are small in size, the efficiency and self-cleaning effect of the photocatalysts are very high.

Claims

1. A method to prepare titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

, wherein 0<

X+δ

<

0.22, 0<

X<

0.2, and 0<

δ

<

0.02, comprising;

(1) formation process of forming a thin film on a substrate using an inert gas, a mixed gas consisted of N₂ and CO, and a metal Ti by a reactive sputtering; and

(2) heat treatment process wherein the formed thin film is heat treated at a temperature between 450°

C. and 500°

C. for 2 to 4 hours.

2. The method to prepare titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 1, wherein the inert gas is argon (Ar) gas.

3. The method to prepare titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 1, wherein the substrate can be any one selected from the group consisting of glass, metal and ceramic plates.

4. The method to prepare titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 1, wherein the mixed gas has N₂;

CO ratio of 10;

1 to 5;

6.

5. The method to prepare titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 4, wherein the heat treatment process (2) is performed at 500°

C. for 4 hours.

6. Titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

, wherein 0<

X+δ

<

0.22, 0<

X<

0.2, and 0<

δ

<

0.02, prepared by using the method of claim 1.

7. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 6 characterized by having anatase crystallization phase.

8. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 6, wherein the thin film has an average diameter of 30 nm or less.

9. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 6, wherein x=δ

.

10. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 6, wherein x>

δ

.

15. The method to prepare titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 2, wherein the mixed gas has N₂;

CO ratio of 10;

1 to 5;

6.

16. The method to prepare titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 3, wherein the mixed gas has N₂;

CO ratio of 10;

1 to 5;

6.

17. Titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

, wherein 0<

X+δ

<

0.22, 0<

X<

0.2, and 0<

δ

<

0.02, prepared by using a method of claim 2.

18. Titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

, wherein 0<

X+δ

<

0.22, 0<

X<

0.2, and 0<

δ

<

0.02, prepared by using a method of claim 3.

19. Titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

, wherein 0<

X+δ

<

0.22, 0<

X<

0.2, and 0<

δ

<

0.02, prepared by using a method of claim 5.

20. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 7, wherein x=δ

.

21. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 8, wherein x=δ

.

22. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 7, wherein x>

δ

.

23. The titanium oxide-based photocatalysts and self-cleaning materials having a general formula of TiO_2-X-δ

C_XN_δ

of claim 8, wherein x>

δ

.

11. Titanium oxide-based material having a general formula of TiO_2-X-δ

C_XN_δ

, wherein 0<

X+δ

<

0.22, 0<

X<

0.2, and 0<

δ

<

0.02.

12. The titanium oxide-based material having a general formula of TiO_2-X-δ

C_XN_δ

of claim 11 characterized by having an anatase crystallization phase.

13. The titanium oxide-based thin film material having a general formula of TiO_2-X-δ

C_XN_δ

of claim 11, wherein x=δ

.

14. The titanium oxide-based thin film material having a general formula of TiO_2-X-δ

C_XN_δ

of claim 11, wherein x>

δ

.

24. The titanium oxide-based thin film material having a general formula of TiO_2-X-δ

C_XN_δ

of claim 12, wherein x=δ

.

25. The titanium oxide-based thin film material having a general formula of TiO_2-X-δ

C_XN_δ

of claim 12, wherein x>

δ

.