Titanium oxide photocatalyst and method for producing the same

• US 8,148,289 B2
• Filed: 04/18/2008
• Issued: 04/03/2012
• Est. Priority Date: 04/18/2007
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation), Sakai Chemical Industry Company Limited
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation), Sakai Chemical Industry Company Limited
• Inventors: Taniguchi, Noboru, Tokumitsu, Shuzo, Kuroha, Tomohiro, Tokuhiro, Kenichi, Nakashima, Akio, Kobayashi, Keita, Nakahara, Shinji
• Primary Examiner(s): Hailey, Patricia L
• Application Number:
  US12/596,293
• Publication Number:
  US 20100111817A1
• Time in Patent Office: 1,446 Days
• Field of Search: 502/224, 502/350, 423/610
• US Class Current: 502/224
• CPC Class Codes: A61L 9/18 Radiation A61L9/22 takes precedence
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 27/135 with titanium, zirconium, hafnium, germanium, tin or lead
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 37/26 Fluorinating
• CPC Class Codes: C01G 23/00 Compounds of titanium preparation of Ti-compounds from ores or scraps C22B34/12
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01P 2002/54 one element only
• CPC Class Codes: C01P 2006/12 Surface area

Abstract

A titanium oxide photocatalyst that is capable of improving a decomposition rate, and a method for producing the same are provided. The titanium oxide photocatalyst of the present invention is a titanium oxide photocatalyst containing at least an anatase-type titanium oxide and fluorine, wherein a content of the fluorine is 2.5 wt % to 3.5 wt %, and 90 wt % or more of the fluorine is chemically bonded to the anatase-type titanium oxide.

Claims

1. A method for producing a titanium oxide photocatalyst containing at least an anatase-type titanium oxide and fluorine, the method comprising the steps of:

mixing a fluorine compound and an aqueous dispersion solution of an anatase-type titanium oxide that absorbs n-butylamine in an amount of 8 μ

mol/g or less, and when a pH of the mixed solution exceeds 3, adjusting the pH at 3 or less with an acid, whereby the titanium oxide and the fluorine compound are caused to react with each other in the mixed solution; and

washing a reaction product obtained by the reaction, whereby a titanium oxide photocatalyst is obtained that contains at least the anatase-type titanium oxide and the fluorine, wherein a content of the fluorine is 2.5 wt % to 3.5 wt %, and, of an entirety of the fluorine, a proportion of fluorine chemically bonded to the anatase-type titanium oxide is 90 wt % or more.

2. The method for producing a titanium oxide photocatalyst according to claim 1, wherein the content of sodium in the anatase-type titanium oxide in the aqueous dispersion solution is 1000 wt ppm or less.

3. The method for producing a titanium oxide photocatalyst according to claim 2,

wherein the washing step is a step of washing the reaction product with water and

the reaction product is washed until an electric conductivity of water collected after the washing becomes 1 mS/cm or less.

4. The method for producing a titanium oxide photocatalyst according to claim 1,

wherein the washing step is a step of washing the reaction product with water and

the reaction product is washed until an electric conductivity of water collected after the washing becomes 1 mS/cm or less.

5. A method for producing a titanium oxide photocatalyst containing at least an anatase-type titanium oxide and fluorine, the method comprising the steps of:

adjusting a pH of an aqueous dispersion solution of a titanium oxide with an alkaline solution until the pH thereof becomes in a range of 7.5 to 9.5, and thereafter filtering the solution;

re-dispersing a filtration residue obtained by the filtration into water;

obtaining a suspension by adding a fluorine compound to the re-dispersion solution obtained by the re-dispersion, and thereafter adjusting a pH of the suspension with an acid until the pH thereof becomes 3 or less, whereby the titanium oxide and the fluorine compound are caused to react with each other; and

washing a reaction product obtained by the reaction, whereby a titanium oxide photocatalyst is obtained that contains at least the anatase-type titanium oxide and the fluorine, wherein a content of the fluorine is 2.5 wt % to 3.5 wt %, and, of an entirety of the fluorine, a proportion of the fluorine chemically bonded to the anatase-type titanium oxide is 90 wt % or more.

6. The method for producing a titanium oxide photocatalyst according to claim 5, wherein the alkaline solution contains at least one selected from the group consisting of ammonia water, an aqueous ammonium carbonate solution, and an aqueous hydrazine solution.

7. The method for producing a titanium oxide photocatalyst according to claim 6,

wherein the washing step is a step of washing the reaction product with water and

the reaction product is washed until an electric conductivity of water collected after the washing becomes 1 mS/cm or less.

8. The method for producing a titanium oxide photocatalyst according to claim 5,

wherein the washing step is a step of washing the reaction product with water and

the reaction product is washed until an electric conductivity of water collected after the washing becomes 1 mS/cm or less.