Member having photocatalytic function and method for manufacture thereof

• US 20050233899A1
• Filed: 12/24/2002
• Published: 10/20/2005
• Est. Priority Date: 12/21/2001
• Status: Active Grant

• Current Assignee: Nippon Sheet Glass Company Limited
• Original Assignee: Nippon Sheet Glass Company Limited
• Inventors: Mori, Kenji, Anzaki, Toshiaki, Kijima, Yoshifumi
• Granted Patent: US 7,612,015 B2
• Time in Patent Office: Days
• US Class Current: 502/350
• CPC Class Codes: A01N 2300/00 Combinations or mixtures of active ingredients covered by classes A01N27/00 - A01N65/48 with other active or formulation relevant ingredients, e.g. specific carrier materials or surfactants, covered by classes A01N25/00 - A01N65/48
• CPC Class Codes: A01N 25/08 containing solids as carriers or diluents
• CPC Class Codes: A01N 25/34 Shaped forms, e.g. sheets, not provided for in any other sub-group of this main group
• CPC Class Codes: A01N 59/16 Heavy metals; Compounds thereof
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2218/36 Underside coating of a glass sheet
• CPC Class Codes: C23C 14/024 Deposition of sublayers, e.g. to promote adhesion of the coating C23C14/027 takes precedence
• CPC Class Codes: C23C 14/083 of refractory metals or yttrium

Abstract

A photocatalyst layer (TiO₂) is formed on the surface of a substrate (glass plate) through the intermediary of a monoclinic undercoat layer (ZrO₂), and no dead layer is substantially present between the photocatalyst layer and the undercoat layer. Also, by providing a peel preventing layer between the substrate and the undercoat layer, it is possible to eliminate film peeling between the photocatalyst layer and the substrate, defects and discoloration. In the above-described TiO₂ layer, metal such as tin (Sn), zinc (Zn), molybdenum (Mo) or iron (Fe) is doped. The phrase “no dead layer is substantially present” means that the thickness of the dead layer is 20 nm or less. The thickness of the photocatalyst layer is preferably from 1 nm to 1,000 nm, more preferably from 1 nm to 500 nm.

Claims

1. A member having a photocatalytic function comprising:

a substrate;

an undercoat layer provided on said substrate; and

a photocatalyst layer formed on said undercoat layer,

wherein said undercoat layer is crystalline, said photocatalyst layer is constituted of a crystalline phase, and no dead layer which is observed as a halo pattern in an electron diffraction image is substantially present between said undercoat layer and said photocatalyst layer.

2. A member having a photocatalytic function comprising:

a substrate;

a peel preventing layer, whose main component is an oxide, an oxynitride or a nitride of at least one of silicon and tin, provided on the surface of said substrate;

an undercoat layer provided on said peel preventing layer; and

a photocatalyst layer formed on the surface of said undercoat layer,

wherein said undercoat layer is crystalline, said photocatalyst layer is constituted of a crystalline phase, and no dead layer which is observed as a halo pattern in an electron diffraction image is substantially present between said undercoat layer and said photocatalyst layer.

3. The member having a photocatalytic function according to claim 2, wherein the thickness of said peel preventing layer is from 2 nm to 200 nm.

4. The member having a photocatalytic function according to claim 2, wherein said substrate is a glass plate manufactured by a float process, and said peel preventing layer is a tin modification layer formed on the bottom face of said glass plate at the time of manufacturing said glass plate.

5. The member having a photocatalytic function according to claim 2, wherein the thickness of said dead layer is 0 nm or more and 20 nm or less.

6. The member having a photocatalytic function according to claim 2, wherein the thickness of said photocatalyst layer is from 1 nm to 1,000 nm.

7. The member having a photocatalytic function according to claim 2, wherein the thickness of said undercoat layer is from 1 nm to 500 nm.

8. The member having a photocatalytic function according to claim 2, wherein the particulates which constitute said photocatalyst layer are formed continuously from the interface with the undercoat layer to the surface of the photocatalyst layer.

9. The member having a photocatalytic function according to claim 8, wherein the width of the particulates which constitute said photocatalyst layer along the direction parallel to the substrate is 5 nm or more.

10. The member having a photocatalytic function according to claim 2, wherein said undercoat layer and said photocatalyst layer, are comprised of a metal oxide or a metal oxynitride which is crystalline, and at least one of the distances between oxygen atoms in the crystals which constitute the undercoat layer is in the range from 90 to 110% with respect to at least one of the distances between oxygen atoms in the crystals which constitute the photocatalyst layer.

11. The member having a photocatalytic function according to claim 2, wherein the main component of said undercoat layer is a crystalline zirconium compound and the main component of said photocatalyst layer is a titanium compound.

12. The member having a photocatalytic function according to claim 11, wherein said crystalline zirconium compound includes monoclinic zirconium oxide crystals.

13. The member having a photocatalytic function according to claim 12, wherein the electron diffraction image obtained by perpendicularly irradiating the cross section of the layer includes the electron diffraction image from the (111) plane or the (−

111) plane of the monoclinic crystal of zirconium oxide, and the interplanar spacing with respect to the (111) orientation plane measured by the electron diffraction image or by a bright-field image of a transmission electron microscope (TEM) is 2.6 to 3.0 Å

, and the interplanar spacing with respect to the (−

111) orientation plane measured by the same method is 3.0 to 3.5 Å

.

14. The member having a photocatalytic function according to claim 11, wherein said titanium compound is tetragonal titanium oxide.

15. The member having a photocatalytic function according to claim 14, wherein said titanium compound is anatase type titanium oxide.

16. The member having a photocatalytic function according to claim 15, wherein the electron diffraction image obtained by perpendicularly irradiating the cross section of the layer includes the electron diffraction pattern from the (101) plane of the crystal of anatase type titanium oxide, and the interplanar spacing with respect to the (101) orientation plane measured by the electron diffraction image or by a bright-field image of a transmission electron microscope (TEM) is 3.3 to 3.7 Å

.

17. The member having a photocatalytic function according to claim 2, wherein a metal element is doped in said photocatalyst layer.

18. The member having a photocatalytic function according to claim 17, wherein said metal element is at least one of Sn, Zn and Mo.

19. The member having a photocatalytic function according to claim 17, wherein the addition amount of said metal element is 0.1 mass % or more and 1.0 mass % or less.

20. The member having a photocatalytic function according to claim 17, wherein the addition amount of said metal element is 0.2 mass % or more and 0.5 mass % or less.

21. The member having a photocatalytic function according to claim 17, wherein said metal element is Fe and the addition amount thereof is 0.001 mass % or more and 1.0 mass % or less.

22. The member having a photocatalytic function according to claim 2, wherein said photocatalyst layer is a titanium tin composite oxide layer or a titanium tin mixed oxide layer.

23. The member having a photocatalytic function according to claim 22, wherein the content of tin in said photocatalyst layer is 3 atomic % or more and 50 atomic % or less based on the ratio of the number of tin atoms with respect to the total number of titanium atoms and tin atoms.

24. The member having a photocatalytic function according to claim 2, wherein a hydrophilic thin film is formed on the surface of said photocatalyst layer.

25. The member having a photocatalytic function according to claim 24, wherein said hydrophilic thin film is made of at lease one oxide selected from the group consisting of silicon oxide, zirconium oxide, germanium oxide and aluminum oxide.

26. The member having a photocatalytic function according to claim 25, wherein said hydrophilic thin film is made of silicon oxide.

27. The member having a photocatalytic function according to claim 24, wherein said hydrophilic thin film is porous.

28. The member having a photocatalytic function according to claim 24, wherein the thickness of said hydrophilic thin film is 1 nm or more and 30 nm or less.

29. The member having a photocatalytic function according to claim 24, wherein the thickness of said hydrophilic thin film is 1 nm or more and 20 nm or less.

30. The member having a photocatalytic function according to claim 2, wherein at least said undercoat layer and said photocatalyst layer are formed by a vapor phase method.

31. The member having a photocatalytic function according to claim 30, wherein said vapor phase method is a sputtering method.

32. A method for manufacturing a photocatalytic member comprising the steps of:

forming a peel preventing layer whose main component is an oxide, an oxynitride or a nitride containing at least one of silicon and tin on the surface of a substrate;

forming a monoclinic zirconium oxide layer at low temperature on said peel preventing layer; and

forming a photocatalyst layer constituted of a crystalline phase on said monoclinic zirconium oxide layer.

33. The method for manufacturing a photocatalytic member according to claim 32, wherein said monoclinic zirconium oxide layer is formed at temperature of 150°

C. or below.

34. The method for manufacturing a photocatalytic member according to claim 32, wherein said monoclinic zirconium oxide layer is formed by a sputtering method.