Titanium oxide particle, composition for forming photocatalyst, and photocatalyst

1. A titanium oxide particle, comprising:

a core of titanium oxide; and

a metal compound having a hydrocarbon group, which is bonded to a surface of the core through an oxygen atom,

wherein the titanium oxide particle absorbs light having a wavelength of 450 nm and light having a wavelength of 750 nm,

an element ratio C/Ti between carbon C and titanium Ti on a surface on the titanium oxide particles is from 0.3 to 1.2, and

the element ratio of C/Ti on the surface of the titanium oxide particle after irradiation with an ultraviolet ray having a wavelength of 352 nm and at an irradiation intensity of 1.3 mW/cm 2 for 20 hours is reduced in an amount from 0.1 to 0.9.

2. The titanium oxide particle according to claim 1 ,

which has an absorption in a whole range of a wavelength of 400 nm to 800 nm in a visible absorption spectrum.

3. The titanium oxide particle according to claim 1 , which is prepared by subjecting a core of titanium oxide to a surface treatment with a metal-containing compound to obtain the titanium oxide particle,

the metal-containing compound being a compound represented by R 1 n SiR 2 m wherein R 1 represents an aliphatic hydrocarbon group or an aromatic hydrocarbon group which has 1 to 20 carbon atoms and is saturated or unsaturated, R 2 represents a halogen atom or an alkoxy group, n represents an integer of 1 to 3, m represents an integer of 1 to 3, provided that n+m=4 is satisfied, when n represents an integer of 2 or 3, plural R 1 's may be the same or different, and when m represents an integer of 2 or 3, plural R 2 's may be the same or different.

4. The titanium oxide particle according to claim 3 ,

wherein R 1 is a straight chain shape saturated aliphatic hydrocarbon group.

5. The titanium oxide particle according to claim 3 ,

wherein R 1 is a hexyl group.

6. The titanium oxide particle according to claim 3 , wherein R 1 is an aromatic hydrocarbon group having 6 to 18 carbon atoms.

7. The titanium oxide particle according to claim 6 ,

wherein R 1 is a phenyl group.

8. The titanium oxide particle according to claim 3 ,

wherein R 2 is an alkoxy group having 1 to 10 carbon atoms.

9. The titanium oxide particle according to claim 3 ,

wherein R 2 is a methoxy group.

10. The titanium oxide particle according to claim 3 ,

wherein R 2 is a chlorine atom.

11. The titanium oxide particle according to claim 1 ,

which has a volume average particle diameter of from 10 nm to 1 μm.

12. A composition for forming a photocatalyst, comprising:

the titanium oxide particle according to claim 1 ; and

at least one compound selected from the group consisting of a dispersion medium and a binder.

13. The composition for forming a photocatalyst according to claim 12 ,

wherein the dispersion medium contains water or an organic solvent.

14. The composition for forming a photocatalyst according to claim 13 ,

wherein the organic solvent is an alcohol solvent.

15. The composition for forming a photocatalyst according to claim 12 ,

wherein the binder comprises at least one selected from the group consisting of a fluorine resin, a silicone resin, a polyester resin, and an acrylic resin.

16. The composition for forming a photocatalyst according to claim 12 ,

comprising a coloring material included in the binder.

17. A photocatalyst comprising the titanium oxide particle according to claim 1 .

18. The photocatalyst according to claim 17 , further comprising a promotor.

19. The photocatalyst according to claim 17 , further comprising an antiseptic agent.

20. The photocatalyst according to claim 17 , further comprising a thickener.