Photocatalyst, preparation method and application thereof

The invention relates to an organic waste water decoloration treatment technology, in particular to a photocatalyst, a preparation method and application thereof. The grain size of the photocatalyst is 1 to 100 nanometers; nano cuprous oxide particles are attached to the surface of fine kieselguhr to form a nano cuprous oxide/kieselguhr carrier photocatalyst, wherein the weight ratio of cuprous oxide to kieselguhr is (0.58-0.87) to (1.0-2.0). By using the nano cuprous oxide/kieselguhr carrier photocatalyst, visible light or sunshine can be used as a light source for decoloration of organic colored waste water of pharmacy, papermaking or printing and dyeing industries. The production process is simple, industrialization is easy to realize, the problem of solid and liquid separation in the process of producing nano Cu2O by a hydrolysis method is solved, nanoparticles are effectively prevented from being agglomerated and the photocatalyst can be conveniently recycled and utilized.