Photocatalyst and process for the preparation thereof

• US 6,074,981 A
• Filed: 04/03/1998
• Issued: 06/13/2000
• Est. Priority Date: 08/05/1996
• Status: Expired due to Fees

• Current Assignee: Nippon Sheet Glass Company Limited, NSG Techno-Research Co., Ltd. (Nippon Sheet Glass Company Limited)
• Original Assignee: Nippon Sheet Glass Company Limited, NSG Techno-Research Co., Ltd. (Nippon Sheet Glass Company Limited)
• Inventors: Hattori, Akihiko, Shimoda, Koji, Ito, Toshiya, Tada, Hiroaki
• Primary Examiner(s): Wood, Elizabeth D.
• Application Number:
  US09/051,223
• Time in Patent Office: 802 Days
• Field of Search: 502/224, 502/227, 502/226, 502/228, 502/229, 502/230, 502/231
• US Class Current: 502/224
• CPC Class Codes: B01D 2255/802 Photocatalytic
• CPC Class Codes: B01D 53/8687 Organic components
• CPC Class Codes: B01D 53/885 Devices in general for catalytic purification of waste gases
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: C03C 17/256 Coating containing TiO2
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/212 TiO2
• CPC Class Codes: C03C 2217/241 with halides
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2218/10 Deposition methods

Abstract

Fluorine contained within a photocatalyst layer containing titanium oxide and other metallic oxide semiconductors increases the metallic oxide'"'"'s photocatalytic activity. The described photocatalyst may be in the form of either film, flake, particulate, or fiber. In addition, it can be used for coating the surface of a base material of various forms, such as sheet, film, flake, particulate, bar, or fiber. When using a base material that has an alkaline-containing glass composition, establishing a fluorine-containing layer, such as a layer of fluorine-containing silicon dioxide and other metallic oxide, between the photocatalyst film and the base material can prevent the deterioration of photocatalytic activity of the photocatalyst layer. The fluorine-containing layer functions as an alkaline barrier that controls the diffusion and migration of alkali metallic ions in the glass fibers, such as Na ions, into the photocatalyst layer. Inorganic fiber- and glass sheet-based photocatalyst bearing materials have an excellent capability to decompose rarefied harmful organic gases, and are suitable for use as interior wall and air filters in super clean enclosed spaces and conveyance spaces for semiconductor production, clean rooms for various other purposes, and office and residential buildings, and for other purposes including air cleaning, antibacterial action, anti-fouling action, and defogging of clear sheets (maintaining hydrophilicity).

Claims

1. A photocatalyst consisting essentially of a fluorine-doped metallic oxide semiconductor, wherein said photo catalyst is in the form of a film, flake, powder or fiber.

2. The photocatalyst according to claim 1 having a thickness or a minimum size of 20-500 nm.

3. The photocatalyst according to claim 1 wherein said metallic oxide is a titanium oxide.