Member having photocatalytic function and method for manufacture thereof

A member having a photocatalytic function comprising:

• a substrate;
• a peel preventing layer, whose main component is an oxide, an oxynitride or a nitride of at least one of silicon and tin, provided on a surface of said substrate;
• an undercoat layer provided on said peel preventing layer, the undercoat layer including monoclinic zirconium oxide;
• and
• a photocatalyst layer formed on a surface of said undercoat layer, the photocatalyst layer including anatase type titanium dioxide,
• wherein said undercoat layer is crystalline, said photocatalyst layer is constituted of a crystalline phase, and no dead layer which is observed as a halo pattern in an electron diffraction image is substantially present between said undercoat layer and said photocatalyst layer,
• wherein an electron diffraction image obtained by perpendicularly irradiating a cross section of the undercoat layer includes an electron diffraction image from a (111) orientation plane or a (−111) plane of the monoclinic zirconium oxide, an interplanar spacing with respect to the (111) orientation plane measured by an electron diffraction image or by a bright-field image of a transmission electron microscope (TEM) is 2.6 to 3.0 Å, and an interplanar spacing with respect to the (−111) orientation plane measured by the an electron diffraction image or by a bright field image of a transmission electron microscope (TEM) is 3.0 to 3.5 Å, and wherein at least one of the distances between oxygen atoms in crystals which constitute the undercoat layer is in the range from 90 to 110%with respect to at least one of the distances between oxygen atoms in crystals which constitute the photocatalyst layer.

A method for manufacturing a photocatalytic member comprising the steps of:

• forming a peel preventing layer whose main component is an oxide, an oxynitride or a nitride containing at least one of silicon and tin on the surface of a substrate;
• forming an undercoat layer including monoclinic zirconium oxide at low temperature on said peel preventing layer;
• and
• forming a photocatalyst layer including anatase type titanium dioxide on said undercoat layer, wherein said undercoat layer is crystalline, said photocatalyst layer is constituted of a crystalline phase, and no dead layer which is observed as a halo pattern in an electron diffraction image is substantially present between said undercoat layer and said photocatalyst layer,
• wherein an electron diffraction image obtained by perpendicularly irradiating a cross section of the undercoat layer includes an electron diffraction image from a (111) orientation plane or a (−111) plane of the monoclinic zirconium oxide, an interplanar spacing with respect to the (111) orientation plane measured by an electron diffraction image or by a bright-field image of a transmission electron microscope (TEM) is 2.6 to 3.0 Å, and an interplanar spacing with respect to the (−111) orientation plane measured by the an electron diffraction image or by a bright field image of a transmission electron microscope (TEM) is 3.0 to 3.5 Å.