Defects and interface states related photocatalytic properties in reduced and subsequently nitridized Fe3O4/TiO2

The Fe3O4@TiO2 catalyst was reduced in a mixed H-2/N-2 atmosphere at temperatures of 400, 600, 800 and 1000 degrees C in order to produce the oxygen vacancies (O-v) and Ti3+ Simultaneously, Fe3O4 was reduced to Fe, a strongly magnetic material, beneficial for the magnetic separation after the photo-degradation. The optimal catalyst was obtained at the reducing temperature of 800 degrees C, which possesses the good photocatalytic performance and recycled activities; Moreover, its saturation magnetization M-s is highest, reaching 23.8 emu g(-1) which improves the magnetic separability. This optimal catalyst was subsequently treated in the NH(3)atmosphere at temperatures of 500, 600 and 700 degrees C, aiming to investigate the effects of N-doping in TiO2. The 600 degrees C treated catalyst exhibited the optimal photocatalytic performance. The factors that affect the photocatalytic performance are revealed and discussed in detail, including the ratio of O-v and N dopant in TiO2 as well as the interface states between TiO2 and the magnetic particles. (C) 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.