Titanium dioxide nanoparticles co-doped with Fe3+ and Eu3+ ions for photocatalysis

Nanoparticles of titanium dioxide co-doped with Fe3+ and Eu3+ were prepared using the sol-gel method. The photocatalytic reactivities were evaluated by photodegradation of chloroform in solution. Nanocrystalline TiO2 co-doped with Eu3+ and Fe3+ at optimal concentration (1 at.% Fe3+, 0.5 at.% Eu3+) shows a synergistic effect, which significantly increases the photodegradation activity of nano-TiO2. The effects of the dopants in nanocrystalline TiO2 particles on the photocatalysis were studied using the photo-electrochemical method. Two dopants of Fe3+ and Eu3+ in nanocrystalline TiO2 play different roles in improving the photoinduced charge separation in the nanostructured semiconductor and in the interfacial charge transfer process at the semiconductor/solution interface. Fe3+ serves as a hole trap and Eu3+ as an electron trap in nanocrystalline TiO2, respectively. The separation of the charge carriers is attributed to such trappings. In the meantime, Fe3+ and Eu3+ also speed up anodic and cathodic processes via improving interfacial charge transfers. Superior photocatalysis of nanocrystalline TiO2 co-doped with Fe3+ and Eu3+ ions was related to the cooperative actions of the two dopants. (C) 2002 Elsevier Science B.V All rights reserved.