Abstract: Titanium oxide-based photocatalysts which contain a metal halide in titanium oxide and which are prepared from titanium oxide and/or its precursor, which may optionally be heat treated, by contact with a reactive gas containing a metal halide of the formula MXn or MOXn (wherein M=a metal, X=a halogen, and n=an integer) with heating stably develop a high photocatalytic activity with visible light irradiation. The photocatalysts may subsequently be stabilized by contact with water or by heat treatment, and/or promoted by contact with a heteropoly acid and/or an isopoly acid so as to include a metal complex in the titanium oxide. Photocatalysts prepared in this manner exhibit novel ESR features. The present invention also provides methods for preparing these photocatalysts, a photocatalyst dispersion and a photocatalytic coating fluid containing such a photocatalyst, and photocatalytic functional products and methods for their manufacture using the photocatalyst.

Abstract: A titanium oxide photocatalyst responsive to visible light which can exhibit a high photocatalytic activity in response to visible light is produced by subjecting titanium oxide and/or titanium hydroxide obtained by neutralizing an acidic titanium compound with a nitrogen-containing base to heat treatment in an atmosphere containing a hydrolyzable metal compound (e.g., a titanium halide) and then to additional heat treatment in a gas having a moisture content of 0.5-4.0 volume % at a temperature of 350° C. or above. The photocatalyst which is a nitrogen-containing titanium oxide has no substantial peak at a temperature of 600° C. or above in a mass fragment spectrum obtained by thermal desorption spectroscopy in which the ratio m/e of the mass number m to the electric charged e of ions is 28, and the peak having the smallest half band width is in the range of 400-600° C. in the spectrum. The nitrogen content calculated from the peak appearing at 400 eV±1.

Abstract: Titanium oxide-based photocatalysts which contain a metal halide in titanium oxide and which are prepared from titanium oxide and/or its precursor, which may optionally be heat treated, by contact with a reactive gas containing a metal halide of the formula MXn or MOXn (wherein M=a metal, X=a halogen, and n=an integer) with heating stably develop a high photocatalytic activity with visible light irradiation. The photocatalysts may subsequently be stabilized by contact with water or by heat treatment, and/or promoted by contact with a heteropoly acid and/or an isopoly acid so as to include a metal complex in the titanium oxide. Photocatalysts prepared in this manner exhibit novel ESR features. The present invention also provides methods for preparing these photocatalysts, a photocatalyst dispersion and a photocatalytic coating fluid containing such a photocatalyst, and photocatalytic functional products and methods for their manufacture using the photocatalyst.

Abstract: A highly active titanium oxide photocatalyst of the type responsive to visible light is prepared by subjecting a titanium (hydr)oxide raw material obtained by neutralizing an acidic titanium compound in ammonia or an amine under conditions such that the final pH is 7 or below to heat treatment in an atmosphere containing a hydrolyzable compound followed by contact with water and additional heat treatment at a temperature of at least 350° C. The resulting titanium oxide photocatalyst comprises titanium oxide with a specific surface area of at most 120 m2/g and with the amount of surface hydroxyl groups being at least 600 ?eq/g. Preferably the density of surface hydroxyl groups is at least 8 ?eq/m2, and the ratio of the amount of terminal type hydroxyl groups (T) to the amount of bridge type hydroxyl groups (B) in the surface hydroxyl groups satisfies T/B?0.20. This titanium oxide photocatalyst has an ESR spectrum having two types of triplet signal for which the g values of the main spectra are 1.993-2.

Abstract: A photocatalytic composite material having a photocatalytic titanium oxide film on the surface of a substrate is produced by a CVD method in which TiCl4 vapor is reacted with water vapor. The TiCl4 vapor and the water vapor are injected into a vapor deposition chamber (9) through nozzles (5) and (6), respectively, such that the resulting two injected vapor streams meet before reaching the substrate, thereby mixing the two vapors. Within 3 seconds after this mixing, the mixed vapors are brought into contact with a substrate (1) which is moving in one direction. Preferably the TiCl4 vapor is injected in a reverse direction with respect to the direction of movement of the substrate through a multi-orifice nozzle (5), while the water vapor is injected through a slit nozzle (6) disposed at a smaller angle with respect to the substrate.

Abstract: Titanium oxide-based photocatalysts which contain a metal halide in titanium oxide and which are prepared from titanium oxide and/or its precursor, which may optionally be heat treated, by contact with a reactive gas containing a metal halide of the formula MXn or MOXn (wherein M=a metal, X=a halogen, and n=an integer) with heating stably develop a high photocatalytic activity with visible light irradiation. The photocatalysts may subsequently be stabilized by contact with water or by heat treatment, and/or promoted by contact with a heteropoly acid and/or an isopoly acid so as to include a metal complex in the titanium oxide. Photocatalysts prepared in this manner exhibit novel ESR features. The present invention also provides methods for preparing these photocatalysts, a photocatalyst dispersion and a photocatalytic coating fluid containing such a photocatalyst, and photocatalytic functional products and methods for their manufacture using the photocatalyst.