Defects and interface states related photocatalytic properties in reduced and subsequently nitridized Fe_3O_4/TiO_2

摘要

The Fe_3O_4@TiO_2 catalyst was reduced in a mixed H_2/N_2 atmosphere at temperatures of 400, 600, 800 and 1000?C in order to produce the oxygen vacancies(O_v) and Ti^(3+); Simultaneously, Fe_3O_4 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?C, which possesses the good photocatalytic performance and recycled activities; Moreover, its saturation magnetization Msis 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?C, aiming to investigate the effects of N-doping in TiO_2. The 600?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 Ovand N dopant in TiO_2 as well as the interface states between TiO_2 and the magnetic particles.