Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Metal – metal oxide or metal hydroxide
Patent
1997-11-25
2000-08-22
Dunn, Tom
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Metal, metal oxide or metal hydroxide
502349, 502522, 423608, 423610, 588205, B01J 2300
Patent
active
061072419
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a photocatalytic body having a good photocatalytic function, a method for making the same, and a photocatalytic composition used therefor.
BACKGROUND TECHNOLOGY
When semiconductors are irradiated with light whose wavelength has an energy greater than a band gap thereof, an oxidation-reduction reaction is brought about. Such a semiconductor is called a photocatalytic semiconductor or merely a photocatalyst.
Photocatalysts are in the form of powder and may be used as suspended in a solution, or may be used as supported on a substrate. From the standpoint of photocatalytic activity, the former is more active owing to the greater surface area. From the standpoint of practical applications, it has been frequently experienced to inevitably adopt the latter rather than the former owing to the ease in handing.
In order to support a photocatalyst on a substrate, there has been adopted a method wherein the particles of a photocatalyst are sintered at high temperatures and supported on the substrate. Another method has been proposed wherein a certain type of fluoropolymer is used as a binder, with which a photocatalyst is supported on a substrate. For instance, Japanese Laid-open Patent Application No. 4-284851 sets out a method wherein a mixture of the particles of a photocatalyst and a fluoropolymer is built up as layers and bonded under compression pressure. Japanese Laid-open Patent Application No. 4-334552 sets forth a method wherein the particles of a photocatalyst are thermally bonded to a fluoropolymer. Moreover, Japanese Laid-open Patent Application No. 7-171408 sets out a method wherein the particles of a photocatalyst is bonded on a substrate through a hard-to-decompose binder including an inorganic binder such as water glass or an organic binder such as a silicone copolymer, and also a method for manufacturing a photocatalytic body which includes, on a substrate, a first layer made of a hard-to-decompose binder, and a second layer formed on the first layer and made of a hard-to-decompose binder and the particles of a photocatalyst. In addition, Japanese Laid-open Patent Application No. 5-309267 describes a method wherein the metal oxide obtained from a metal oxide sol is used to support and fix the powder of a photocatalyst therewith. It is stated that the metal oxide sols are obtained from organometallic compounds such as alkoxides, acetylacetonate, carboxylates of metals as used in a sol-gel method, or are obtained by hydrolysis of an alcohol solution of chlorides, such as titanium tetrachloride, in the presence of an acid or alkali catalyst.
DISCLOSURE OF THE INVENTION
In recent years, attempts have been made to decompose, purify and sterilize harmful substances, offensive odor components and oily components ascribed to daily living environments by use of photocatalysts, thus leading to a quick extension of the application range of photocatalysts. This, in turn, requires a method of causing the particles of a photocatalyst to be firmly supported on all types of substrates over a long time without a sacrifice of its photocatalytic function. Especially, where a titanium oxide sol, which exhibits the good photocatalytic function but is poor in the function of bonding to a substrate, is used as a photocatalyst, it is required to improve the bonding property.
However, in these prior art methods, the bonding strength is not satisfactory, so that few methods ensures the support over a long time. If it is intended to make a photocatalytic body which has an improved bonding strength and ensures the support over a long time, there has arisen the problem that the photocatalytic function lowers. In case where the substrate made of an organic polymer resin is employed and rutile titanium oxide, which is weaker in photocatalytic function than anatase titanium oxide, is used, the photocatalytic reaction proceeds. Not only the organic polymer resin per se undergoes a photochemical reaction, but also the use over a long time results in degradation and decomposition.
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REFERENCES:
patent: 3975197 (1976-08-01), Mikelsons
patent: 4756999 (1988-07-01), Swain et al.
patent: 4918138 (1990-04-01), Hara et al.
patent: 5173215 (1992-12-01), Clarke
patent: 5281496 (1994-01-01), Clarke
patent: 5360833 (1994-11-01), Eckberg et al.
patent: 5462674 (1995-10-01), Butters et al.
patent: 5589078 (1996-12-01), Butters et al.
patent: 5604339 (1997-02-01), Tabatabaie-Raissi et al.
patent: 5616532 (1997-04-01), Heller et al.
patent: 5658841 (1997-08-01), Tanaka et al.
patent: 5668076 (1997-09-01), Yamagushi et al.
patent: 5872072 (1999-02-01), Mouri et al.
Barksdale, Jelks. Titanium. Its Occurrence, Chemistry, and Technology. The Ronald Press Company: New York. Second Edition. Jun. 15, 1967. pp. 76-86.
Matsui Yoshimitsu
Ogata Shiro
Dunn Tom
Kabushiki Kaisha Tanaka Tensha
Nguyen Cam N.
Tao Inc.
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