Photocatalytic material and photocatalytic article

• US 6,794,065 B1
• Filed: 02/05/2002
• Issued: 09/21/2004
• Est. Priority Date: 08/05/1999
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Original Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Inventors: Morikawa, Takeshi, Asahi, Ryoji, Taga, Yasunori, Ohwaki, Takeshi
• Primary Examiner(s): Nguyen, Ngoc-Yen
• Application Number:
  US10/048,933
• Time in Patent Office: 959 Days
• Field of Search: 423/265, 423/266, 423/610, 502/349, 502/350, 502/326, 502/200, 502/216, 502/222, 428/699, 428/701, 428/702, 428/704, 428/690
• US Class Current: 428/699
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 27/24 Nitrogen compounds
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/0238 via the gaseous phase-sublimation
• 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 37/341 making use of electric or magnetic fields, wave energy or particle radiation use of flames, plasma or lasers B01J37/349
• CPC Class Codes: B01J 37/346 of microwave energy
• CPC Class Codes: B01J 37/349 making use of flames, plasmas or lasers
• CPC Class Codes: C01G 23/04 Oxides; Hydroxides
• CPC Class Codes: C01P 2002/54 one element only
• CPC Class Codes: C01P 2002/77 by unit-cell parameters, atom positions or structure diagrams
• CPC Class Codes: C01P 2004/84 one phase coated with the other

Abstract

A photocatalytic material having titanium oxide crystals and anions X incorporated therein, which is prepared by at least one of a method comprising substituting anions X for some of the oxygen sites of titanium oxide crystals, a method comprising doping anions X between lattices of a titanium crystal and a method comprising doping grain boundaries of titanium oxide, or a combination of these method. The photocatalytic material has acquired a new energy level formed in a band gap of titanium oxide, which results in its exhibition of a photocatalytic activity by absorbing visible lights. The photocatalytic material can thus exhibit a satisfactory photocatalytic activity under sunlight and also in a room with a fluorescent lamp.

Claims

1. A photocatalytic material exhibiting a photocatalytic action when exposed to light with a wavelength in the region of ultraviolet light and visible light, comprising a titanium compound Ti—

O—

X obtained by at least one of;

substituting an anion X for a plurality of oxygen sites of titanium oxide crystals,

doping an anion X between lattices of a titanium oxide crystal, and

doping an anion X in grain boundaries of titanium oxide aggregate.

2. The photocatalytic material according to claim 1, wherein said anion X is at least one element selected from the group consisting of B, P, S, Cl, As, Se, Br, Sb, Te, and I, or a molecule containing at least one of these elements.

3. The photocatalytic material according to claim 1, wherein a chemical bond is present between titanium Ti and an anion X.

4. A photocatalytic article comprising the photocatalytic material according to claim 1 and a titanium oxide crystal containing no anions X, formed on the external surface of the photocatalytic material.

5. A photocatalytic article comprising the photocatalytic material according to claim 1, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

6. The photocatalytic material according to claim 2, wherein a chemical bond is present between titanium Ti and an anion X.

7. A photocatalytic article comprising the photocatalytic material according to claim 2 and a titanium oxide crystal containing no anions X, formed on the external surface of the photocatalytic material.

8. A photocatalytic article comprising the photocatalytic material according to claim 3 and a titanium oxide crystal containing no anions X, formed on the external surface of the photocatalytic material.

9. A photocatalytic article comprising the photocatalytic material according to claim 6 and a titanium oxide crystal containing no anions X, formed on the external surface of the photocatalytic material.

10. A photocatalytic article comprising the photocatalytic material according to claim 2, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

11. A photocatalytic article comprising the photocatalytic material according to claim 3, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

12. A photocatalytic article according to claim 4, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

13. A photocatalytic article comprising the photocatalytic material according to claim 6, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

14. A photocatalytic article according to claim 7, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

15. A photocatalytic article according to claim 8, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

16. A photocatalytic article according to claim 9, wherein the photocatalytic material is oriented, on its surface, along the C axis direction of the crystal.

17. A photocatalytic article comprising the photocatalytic material according to claim 1, formed on a substrate.

18. The photocatalytic article according to claim 4, wherein the boundary between the photocatalytic material and the titanium oxide crystal is indistinct, whereby the concentration of anion X gradually decreases toward the surface.

19. The photocatalytic material according to claim 1, which is in the form of a particle.