Patent ID: 7763113

Claim:
A method for producing a photocatalyst material, characterized in that more than one columnar photocatalyst basic structure is fixed to the surface of a substrate, said columnar photocatalyst basic structure consisting of a base portion comprising crystal nuclei that are fixed to the surface of the substrate, and a columnar photocatalyst crystalline body that connects to and is extended from the base portion and has a columnar structure having a hollow portion formed therein, and said columnar structure is quadra prismatic, said base portion consists of crystal nuclei and the photocatalyst constituting said columnar photocatalyst crystalline body is titanium oxide, said columnar photocatalyst crystalline body is formed by a shell portion consisting of a sidewall and an extension direction end and has a columnar shape such that a hollow portion is surrounded by said shell portion, wherein said shell portion is a polycrystalline body consisting of aggregated photocatalyst crystal grains, an aggregate of photocatalyst crystal grains in the hollow portion that is formed inside said columnar photocatalyst crystalline body, and the shell portion of said columnar photocatalyst crystalline body has an interior-exposing structure to expose an internal structure that is the hollow portion of said columnar photocatalyst crystalline body, the method comprises: a gelation step of immersing a substrate, to which crystal nuclei are fixed for use as a base portion of a columnar photocatalyst basic structure, in a sol solution comprising an organic metallic compound or inorganic metallic compound, or applying the sol solution comprising an organic metallic compound or inorganic metallic compound to said crystal nuclei fixed to said substrate, so as to obtain a prototype of a photocatalyst material by gelation; a solidification step of drying and solidifying said prototype obtained by said gelation step; and a heat treatment step of subjecting the solidified prototype to heat treatment so as to form a columnar photocatalyst crystalline body, so that a photocatalyst material is obtained, and said columnar photocatalyst basic structure is quadra prismatic and having a hollow portion formed therein.