Tubular titanium oxide particles, method for preparing the same, and use of the same

• US 20040265587A1
• Filed: 04/29/2004
• Published: 12/30/2004
• Est. Priority Date: 10/30/2001
• Status: Active Grant

• Current Assignee: JGC Catalysts and Chemicals Ltd. (JGC Holdings Corporation)
• Original Assignee: JGC Catalysts and Chemicals Ltd. (JGC Holdings Corporation)
• Inventors: Tanaka, Atsushi, Koyanagi, Tsuguo, Shirono, Katsuhiro, Komatsu, Michio
• Granted Patent: US 7,431,903 B2
• Time in Patent Office: Days
• US Class Current: 428/398
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 21/066 Zirconium or hafnium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/036 to form a gel or a cogel
• CPC Class Codes: B01J 37/16 Reducing
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 23/00 Compounds of titanium preparation of Ti-compounds from ores or scraps C22B34/12
• CPC Class Codes: C01G 23/04 Oxides; Hydroxides
• CPC Class Codes: C01G 23/0536 by hydrolysing chloride-containing salts
• CPC Class Codes: C01G 25/00 Compounds of zirconium
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/13 Nanotubes
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/40 Electric properties
• 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
• CPC Class Codes: Y10T 428/2975 Tubular or cellular
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]

Abstract

The process for preparing tubular titanium oxide particles comprises subjecting a water dispersion sol, which is obtained by dispersing (i) titanium oxide particles and/or (ii) titanium oxide type composite oxide particles comprising titanium oxide and an oxide other than titanium oxide in water, said particles having an average particle diameter of 2 to 100 nm, to hydrothermal treatment in the presence of an alkali metal hydroxide. After the hydrothermal treatment, reduction treatment (including nitriding treatment) may be carried out. The tubular titanium oxide particles obtained in this process are useful as catalysts, catalyst carriers, adsorbents, photocatalysts, decorative materials, optical materials and photoelectric conversion materials. Especially when the particles are used for semiconductor films for photovoltaic cells or photocatalysts, prominently excellent effects are exhibited.

Claims

1. A process for preparing tubular titanium oxide particles, comprising:

subjecting a water dispersion sol, which is obtained by dispersing (i) titanium oxide particles and/or (ii) titanium oxide type composite oxide particles comprising titanium oxide and an oxide other than titanium oxide in water, said particles having an average particle diameter of 2 to 100 nm, to hydrothermal treatment in the presence of an alkali metal hydroxide.

2. The process for preparing tubular titanium oxide particles as claimed in claim 1, wherein reduction treatment (including nitriding treatment) is carried out after the hydrothermal treatment.

3. The process for preparing tubular titanium oxide particles as claimed in claim 1, wherein the hydrothermal treatment is carried out in the presence of ammonium hydroxide and/or an organic base together with the alkali metal hydroxide.

8. The process for preparing tubular titanium oxide particles as claimed in claim 1, wherein the oxide other than titanium oxide is an oxide of one or more elements selected from Group Ia, Group Ib, Group Ia, Group IIb, Group IIIa, Group IIIb, Group IVa, Group IVb, Group Va, Group Vb, Group VIa, Group VIb, Group VIIa and Group VIII of the periodic table.

9. The process for preparing tubular titanium oxide particles as claimed in claim 8, wherein the oxide other than titanium oxide is one or more oxides selected from SiO₂, ZrO₂, ZnO, Al₂O₃, CeO₂, Y₂O₃, Nd₂O₃, WO₃, Fe₂O₃ and Sb₂O₅.

10. The process for preparing tubular titanium oxide particles as claimed in claim 1, wherein the titanium oxide is derived from peroxotitanic acid.

11. Tubular titanium oxide particles obtained by the process of claim 1 and having a sodium content of not more than 0.1% by weight in terms of Na₂O.

25. The process for preparing tubular titanium oxide particles as claimed in claim 2, wherein the hydrothermal treatment is carried out in the presence of ammonium hydroxide and/or an organic base together with the alkali metal hydroxide.

30. The process for preparing tubular titanium oxide particles as claimed in claim 8, wherein the titanium oxide is derived from peroxotitanic acid.

31. The process for preparing tubular titanium oxide particles as claimed in claim 9, wherein the titanium oxide is derived from peroxotitanic acid.

34. Tubular titanium oxide particles obtained by the process of claim 8 and having a sodium content of not more than 0.1% by weight in terms of Na₂O.

35. Tubular titanium oxide particles obtained by the process of claim 9 and having a sodium content of not more than 0.1% by weight in terms of Na₂O.

36. Tubular titanium oxide particles obtained by the process of claim 10 and having a sodium content of not more than 0.1% by weight in terms of Na₂O.

4. A process for preparing tubular titanium oxide particles, comprising:

subjecting a water dispersion sol, which is obtained by dispersing (i) titanium oxide particles and/or (ii) titanium oxide type composite oxide particles comprising titanium oxide and an oxide other than titanium oxide in water, said particles having an average particle diameter of 2 to 100 nm, to hydrothermal treatment in the presence of an alkali metal hydroxide and optionally ammonium hydroxide and/or an organic base, and

then further subjecting the water dispersion sol to hydrothermal treatment in the presence of cation (including proton) other than alkali metal cation.

26. The process for preparing tubular titanium oxide particles as claimed in claim 4, wherein the oxide other than titanium oxide is an oxide of one or more elements selected from Group Ia, Group Ib, Group IIa, Group IIb, Group IIIa, Group IIIb, Group IVa, Group IVb, Group Va, Group Vb, Group VIa, Group VIb, Group VIIa and Group VIII of the periodic table.

28. The process for preparing tubular titanium oxide particles as claimed in claim 4, wherein the titanium oxide is derived from peroxotitanic acid.

32. Tubular titanium oxide particles obtained by the process of claim 4 and having a sodium content of not more than 0.1% by weight in terms of Na₂O.

5. A process for preparing tubular titanium oxide particles, comprising:

subjecting a water dispersion of titanium oxide particles and/or titanium oxide type composite oxide particles comprising titanium oxide and an oxide other than titanium oxide, said particles having an average particle diameter of 2 to 100 nm, to hydrothermal treatment in the presence of an alkali metal hydroxide, and

then subjecting the water dispersion to reduction treatment (including nitriding treatment).

6. The process for preparing tubular titanium oxide particles as claimed in claim 5, wherein ammonium hydroxide and/or one or more organic bases are allowed to be present together with the alkali metal hydroxide.

7. The process for preparing tubular titanium oxide particles as claimed in claim 6, wherein after the hydrothermal treatment in the presence of ammonium hydroxide and/or one or more organic bases together with the alkali metal hydroxide, the water dispersion is treated in the presence of cation other than alkali metal cation or proton to wash the dispersion and then subjected to reduction treatment.

27. The process for preparing tubular titanium oxide particles as claimed in claim 5, wherein the oxide other than titanium oxide is an oxide of one or more elements selected from Group Ia, Group Ib, Group Ia, Group IIb, Group IIIa, Group IIIb, Group IVa, Group IVb, Group Va, Group Vb, Group VIa, Group VIb, Group VIIa and Group VIII of the periodic table.

29. The process for preparing tubular titanium oxide particles as claimed in claim 5, wherein the titanium oxide is derived from peroxotitanic acid.

33. Tubular titanium oxide particles obtained by the process of claim 5 and having a sodium content of not more than 0.1% by weight in terms of Na₂O.

12. Tubular titanium oxide particles represented by the following compositional formula (1):

Ti_aM_bO_xN_y 

 

(1)

wherein a and b are numbers satisfying the conditions of a+b=1 and b=0˜

0.2, x and y are numbers satisfying the conditions of 1≦

x+y<

2, 1≦

x<

2 and 0≦

y<

0.2, and M is an element other than Ti, and

containing titanium oxide as a main component.

13. The tubular titanium oxide particles as claimed in claim 12, having an outer diameter (D_out) of 5 to 40 nm, an inner diameter (D_in) of 4 to 20 nm, a tube thickness of 0.5 to 10 nm, a length (L) of 50 to 1000 nm and a length (L)/outer diameter (D_out) ratio (L/D_out) of 10 to 200.

14. The tubular titanium oxide particles as claimed in claim 12, wherein the element M other than titanium is one or more elements selected from Group Ia, Group Ib, Group IIa, Group IIb, Group IIIa, Group IIIb, Group IVa, Group IVb, Group Va, Group Vb, Group VIa, Group VIb, Group VIIa and Group VIII of the periodic table.

15. The tubular titanium oxide particles as claimed in claim 14, wherein the element M other than titanium is one or more elements selected from Si, Zr, Zn, Al, Ce, Y, Nd, W, Fe and Sb.

37. The tubular titanium oxide particles as claimed in claim 13, wherein the element M other than titanium is one or more elements selected from Group Ia, Group Ib, Group IIa, Group IIb, group IIIa, Group IIIb, Group IVa, Group IVb, Group Va, Group Vb, Group VIa, Group VIb, Group VIIa and Group VIII of the periodic table.

16. A photovoltaic cell comprising:

a substrate having an electrode layer on its surface and having a metal oxide semiconductor film which is formed on a surface of the electrode layer and on which a photosensitizer is adsorbed,

a substrate having an electrode layer on its surface,

both of said substrates being arranged in such a manner that the electrode layer and the electrode layer face each other, and

an electrolyte layer provided between the metal oxide semiconductor film and the electrode layer,

wherein at least one pair of substrate and electrode have transparency, and the metal oxide semiconductor film contains tubular titanium oxide particles.

17. The photovoltaic cell as claimed in claim 16, wherein the tubular titanium oxide particles are represented by the following compositional formula (1):

Ti_aM_bO_xN_y 

 

(1)

wherein a and b are numbers satisfying the conditions of a+b=1 and b=0˜

0.2, x and y are numbers satisfying the conditions of 1≦

x+y<

2, 1≦

x<

2 and 0≦

y<

0.2, and M is an element other than Ti, and

containing titanium oxide as a main component.

18. The photovoltaic cell as claimed in claim 16, wherein the tubular titanium oxide particles have an outer diameter (D_out) of 5 to 40 nm, an inner diameter (D_in) of 4 to 30 nm, a tube thickness of 1 to 20 nm, a length (L) of 25 to 1000 nm and a length (L)/outer diameter (D_out) ratio (L/D_out) of 5 to 200.

19. The photovoltaic cell as claimed in claim 16, wherein the tubular titanium oxide particles have an alkali metal content of not more than 500 ppm.

20. The photovoltaic cell as claimed claim 16, wherein the metal oxide semiconductor film further contains an amorphous titanium oxide binder component.

38. The photovoltaic cell as claimed in claim 17, wherein the tubular titanium oxide particles have an outer diameter (D_out) of 5 to 40 nm, an inner diameter (D_in) of 4 to 30 nm, a tube thickness of 1 to 20 nm, a length (L) of 25 to 1000 nm and a length (L)/outer diameter (D_out) ratio (L/D_out) of 5 to 200.

39. The photovoltaic cell as claimed in claim 17, wherein the tubular titanium oxide particles have an alkali metal content of not more than 500 ppm.

40. The photovoltaic cell as claimed in claim 18, wherein the tubular titanium oxide particles have an alkali metal content of not more than 500 ppm.

41. The photovoltaic cell as claimed in claim 17, wherein the metal oxide semiconductor film further contains an amorphous titanium oxide binder component.

42. The photovoltaic cell as claimed in claim 18, wherein the metal oxide semiconductor film further contains an amorphous titanium oxide binder component.

43. The photovoltaic cell as claimed in claim 19, wherein the metal oxide semiconductor film further contains an amorphous titanium oxide binder component.

21. A photocatalyst using tubular titanium oxide particles.

22. The photocatalyst as claimed in claim 21, wherein the tubular titanium oxide particles are represented by the following compositional formula (1):

Ti_aM_bO_xN_y 

 

(1)

wherein a and b are numbers satisfying the conditions of a+b=1 and b=0˜

0.2, x and y are numbers satisfying the conditions of 1≦

x+y<

2, 1≦

x<

2 and 0≦

y<

0.2, and M is an element other than Ti, and

containing titanium oxide as a main component.

23. The photocatalyst as claimed in claim 21, wherein the tubular titanium oxide particles have an outer diameter (D_out) of 5 to 40 nm, an inner diameter (D_in) of 4 to 30 nm, a tube thickness of 1 to 20 nm, a length (L) of 25 to 1000 nm and a length (L)/outer diameter (D_out) ratio (L/D_out) of 5 to 200.

24. The photocatalyst as claimed in claim 21, wherein the tubular titanium oxide particles have an alkali metal content of not more than 500 ppm.

44. The photocatalyst as claimed in claim 22, wherein the tubular titanium oxide particles have an outer diameter (D_out) of 5 to 40 nm, an inner diameter (D_in) of 4 to 30 nm, a tube thickness of 1 to 20 nm, a length (L) of 25 to 1000 nm and a length (L)/outer diameter (D_out) ratio (L/D_out) of 5 to 200.

45. The photocatalyst as claimed in claim 22, wherein the tubular titanium oxide particles have an alkali metal content of not more than 500 ppm.

46. The photocatalyst as claimed in claim 23, wherein the tubular titanium oxide particles have an alkali metal content of not more than 500 ppm.