The present invention provides for titanium oxide-based photocatalysts having a general formula of TiO.sub.2-X-.delta.C.sub.XN.sub..delta. and self-cleaning materials that are prepared by substituting O of pure TiO2 with C and N. A preparation method comprising a process for forming thin films of TiO.sub.2-X-.delta.C.sub.XN.sub..delta. by using gases such as Ar, N.sub.2, CO.sub.2, CO and O are used for reactive sputtering, and a process of heat treating at around 500.degree. C., thereby crystallizing, is provided. The titanium oxide-based photocatalysts having a general formula of TiO.sub.2-X-.delta.C.sub.XN.sub..delta. and self-cleaning materials according to the present invention have a smaller optical bandgap compared to pure titanium oxides, and therefore, the photocatalysts can be activated under the visible light range. In addition, they comprise only pure anatase crystallization phase, and since the crystallized particles are small in size, the efficiency and self-cleaning effect of the photocatalysts are very high.