Invention relates to water remediation technology and is expected to be used for photocatalysis in visible light, for example, in water purification reactors. The invention is narrow n- and p-type semiconductor system with high oxidation-reduction potential and low photo induced charge carrier recombination, which is provided by Z-scheme charge transfer mechanism. System contains photocatalysts from earth abundant chemical elements. For synthesis of proposed photocatalyst system water based industrializable methods are used. Photocatalyst system Fe2O3/Ca2Fe2O5 can be used for visible light photocatalysis: (i) water purification; (ii) disinfection; (iii) air purification; (iv) sterile surface; (v) water cleavage; (vi) synthesis of chemical compounds from ambient CO2.