Promoting the photocatalytic activity of Bi₄Ti₃O₁₂ microspheres by incorporating iron

Small amounts of Fe(NO₃)₃ were added to the synthesis mixture prior to the hydrothermal synthesis of Bi₄Ti₃O₁₂ microspheres. The physicochemical properties of the resulting materials were changed accordingly. The photocatalytic activities of several samples were studied through the photocatalytic degradation of organic pollutants. The samples with a theoretical Fe atomic percentage of 5.9% showed the highest photocatalytic activity among these samples. The main active species in photocatalytic degradation was demonstrated by radical capturing experiments as h⁺. The introduction of a suitable amount of Fe to the photocatalyst can facilitate the separation of electron-hole pairs generated upon light irradiation, inhibit their recombination efficiently, and prominently expand the light absorption region, thus leading to higher photocatalytic activity.