Crystalline titania having nanotube crystal shape and process for producing the same

• US 6,537,517 B1
• Filed: 08/24/1999
• Issued: 03/25/2003
• Est. Priority Date: 09/30/1996
• Status: Expired due to Fees

• Current Assignee: Chubu Electric Power Company Incorporated
• Original Assignee: Chubu Electric Power Company Incorporated
• Inventors: Kasuga, Tomoko, Hiramatsu, Masayoshi
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US09/382,125
• Time in Patent Office: 1,309 Days
• Field of Search: 423/610
• US Class Current: 423/610
• CPC Class Codes: A61K 2800/413 Nanosized, i.e. having sizes below 100 nm
• CPC Class Codes: A61K 8/02 characterised by special physical form
• CPC Class Codes: A61K 8/29 Titanium; Compounds thereof
• CPC Class Codes: A61Q 17/04 Topical preparations for affording protection against sunlight or other radiation; Topical sun tanning preparations
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 5/00 Nanobiotechnology or nanomedicine, e.g. protein engineering or drug delivery
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/13 Nanotubes
• CPC Class Codes: C01P 2004/17 Nanostrips, nanoribbons or nanobelts, i.e. solid nanofibres with two significantly differing dimensions between 1-100 nanometer
• 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: Y10S 977/734 Fullerenes, i.e. graphene-based structures, such as nanohorns, nanococoons, nanoscrolls or fullerene-like structures, e.g. WS2 or MoS2 chalcogenide nanotubes, planar C3N4, etc.
• CPC Class Codes: Y10S 977/834 Optical properties of nanomaterial, e.g. specified transparency, opacity, or index of refraction
• CPC Class Codes: Y10S 977/843 Gas phase catalytic growth, i.e. chemical vapor deposition
• CPC Class Codes: Y10S 977/896 Chemical synthesis, e.g. chemical bonding or breaking
• CPC Class Codes: Y10T 428/13 Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/131 : Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
• CPC Class Codes: Y10T 428/1314 : Contains fabric, fiber particle, or filament made of glass, ceramic, or sintered, fused, fired, or calcined metal oxide, or metal carbide or other inorganic compound [e.g., fiber glass, mineral fiber, sand, etc.]

Abstract

Crystalline titania of which the crystal shape is a novel nanotube. This crystalline titania is produced by treating crystalline titania with an alkali. This crystalline titania is used as an ultraviolet absorber, a masking agent, an adsorbent and an optically active catalyst.

Claims

1. A process for producing crystalline titania having a nanotube crystal shape which comprises treating a crystalline titania starting material with an alkali to form a crystalline titania having a nanotube crystal shape, wherein the alkali treatment is conducted at a temperature of from 50 to 120°

C. with from 30 to 50 percent by weight of sodium hydroxide in water.

2. The process of claim 1, wherein said alkali treatment is conducted under increased pressure in a sealed vessel.

3. The process of claim 1, wherein after a step of water washing in the alkali treatment, the product is further neutralized.

4. The process of claim 1, wherein after said alkali treatment, the product is further heat-treated at a temperature of from 200 to 1,200°

C. for from 10 to 400 minutes.