Photocatalyst composition

A photocatalyst composition comprising:

• (A) modified photocatalyst particles,
• said modified photocatalyst particles (A) being prepared by subjecting particles of a photocatalyst (a) to a modification treatment with at least one modifier compound (b) selected from the group consisting of different compounds each of which independently comprises at least one structural unit selected from the group consisting of a triorganosilane unit represented by formula (1), a monooxydiorganosilane unit represented by formula (2), and a dioxyorganosilane unit represented by formula (3):
• R3Si— (1)
• wherein each R independently represents a straight chain or branched C1–C30 alkyl group, a C5–C20 cycloalkyl group, a straight chain or branched C1–C30 fluoroalkyl group, a straight chain or branched C2–C30 alkenyl group or a C1–C20 alkoxy group,
• —(R2SiO)— (2)
• wherein each R is as defined for formula (1), and
• wherein R is as defined for formula (1), and
• (B) a binder component which comprises a phenyl group-containing silicone (BP), optionally containing an alkyl group, represented by formula (4):
• R1pR2qXrSiO(4-p-r)/2 (4)
• wherein:
• the or each R1 represents a phenyl group, and the or each R2 independently represents a straight chain or branched C1–C30 alkyl group, a C5–C20 cycloalkyl group or a straight chain or branched C2–C30 alkenyl group;
• the or each X independently represents a hydrogen atom, a hydroxyl group, a C1–C20 alkoxy group, a C1–C20 acyloxy group, an aminoxy group, a C1–C20 oxime group or a halogen atom;
• and
• p, q and r satisfy the following relationships:
• 0<p<4,
• 0≦q<4,
• 0≦r<4,
• 0<(p+q+r)<4, and
• 0.05≦p/(p+q)≦1.