Patent ID: 7799731

Claim:
A photocatalyst, comprising: a photocatalytic film of a compound of titanium and oxygen, wherein the photocatalytic film is an agglomerate of a number of grains, is formed to be porous including gaps among the number of grains at a surface of the photocatalytic film, and has 0.02 or higher value as a value calculated by dividing an arithmetical mean deviation of profile Ra with a film thickness, and the film thickness of the photocatalytic film is not thinner than 40 nm and not thicker than 100 nm, wherein the photocatalytic film is made of titanium oxide formed by sputtering, and the titanium oxide has 100 or less value as an intensity ratio of a ( 101 ) diffraction peak of an anatase structure of titanium oxide to a ( 215 ) diffraction peak of the anatase structure of titanium oxide measured using a Kα characteristic X-ray of copper; the titanium oxide has 5 or less value as the intensity ratio of the ( 101 ) diffraction peak of the anatase structure of titanium oxide to a ( 112 ) diffraction peak of the anatase structure of titanium oxide; and a density of the photocatalytic film is 4.45 g/cm 3 or less.