Enhance the activity of the photocatalyst TiO2-P25 degussa by doping it with N and Mg on degradation of phenol under visible light

Tóm tắt

Catalyst TiO2 with N-doped, Mg-doped and N-Mg co-doped were created by impregnation method with Mg(NO3)2 (add Mg in) and mix method with urea (add N in). The XRD, SEM, DR, BET, FT-IR measurements were carried out for structural characterization of the TiO2 samples. The result performed, compared with the sample of initial TiO2-P25 particle size and specific surface area, samples of doped-catalyst changed insignificantly. The average crystalline size was 30-32 nm, specific surface area about 50 - 60 m2/g. The crystalline phase components did not change, including only anatase and rutile. Doped-catalyst samples narrowed the band gap of TiO2 (values of Eg decreased to under 3.0 eV). In there, N-doped sample possessed the lowest value of Eg (Eg = 2.53 eV), it meant this sample responded to the visible light area obviously. In the degradation of phenol, N-Mg co-doped TiO2 had better catalytic performance than N-doped and Mg-doped alone. The order of doping elements (N and Mg) shown to be an important factor on the catalytic activity of the doping catalysts. The catalysts TiO2 were doped by N first then Mg demonstrated synergic effect and activity of the catalysts increased 1.5- 1.6 times compared with pure TiO2. By contrast, in the reverse order (first Mg then N) the inhibited effect was observed and the catalytic activity would decrease.

Từ khóa: Photocatalyst, N-Mg co-doped TiO2, phenol, degradation

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