Patent ID: 7030058

Claim:
A modified photocatalyst sol comprising a liquid medium having dispersed therein particles of a modified photocatalyst, said particles of a modified photocatalyst being prepared by subjecting particles of a photocatalyst to a modification treatment with at least one modifier compound comprising at least one structural unit selected from the group consisting of a monooxydiorganosilane unit represented by formula (1), a dioxyorganosilane unit represented by formula (2), and a difluoromethylene unit represented by formula (3): —(R 1 R 2 SiO)— (1) wherein each of R 1 and R 2 independently represents a hydrogen atom, a straight chain or branched C 1 –C 30 alkyl group, a C 5 –C 20 cycloalkyl group or a C 6 –C 20 aryl group which is unsubstituted or substituted with at least one substituent selected from the group consisting of a C 1 –C 20 alkyl group, a C 1 –C 20 alkoxy group and a halogen atom, wherein R 1 is as defined for formula (1), and —(CF 2 )— (3), wherein said modifier compound contains at least one silicon atom having bonded thereto at least one hydrogen atom, wherein said modification treatment is conducted in the presence of a dehydrogenation-condensation catalyst which has dehydrogenation-condensation activity with respect to said hydrogen atom bonded to the silicon atom of the modifier compound, said modified photocatalyst particles having a volume mean particle diameter of 800 nm or less.