The surface of a substrate is coated with an abrasion-resistant
photocatalytic coating comprised of a semiconductor photocatalyst. upon
irradiation by a light having a wavelength of an energy higher than the
bandgap energy of the photocatalyst, water is chemisorbed onto the surface
in the form of hydroxyl groups (OH.sup.-) whereby the surface of the
photocatalytic coating is rendered highly hydrophilic. In certain
embodiments, the surface of a mirror, lens, or windowpane is coated with
the photocatalytic coating to exhibit a high degree of antifogging
function. In another embodiment, an article or product coated with the
photocatalytic coating is disposed outdoors and the highly hydrophilic
surface thereof is self-cleaned as it is subjected to rainfall. In a still
another embodiment, an article is coated with the photocatalytic coating
and, when the article is soaked in, rinsed by or wetted with water, fatty
dirt and contaminants are readily released without resort to a detergent.
