Synthesis of N–Si co-doped TiO2 nanoparticles for the photodegradation of phenol

N–Si co-doped TiO 2 nanoparticles for the photodegradation of phenol were prepared by SiCl 4 and TiCl 4 co-hydrolysis and the effect of H 2 O 2 modification was studied. The characterization results revealed that the Si doped into the TiO 2 lattice was limited and the redundant silicon existed in segregated amorphous silica. The average crystallite size of the photocatalysts reduced from 14.8 to 5.5 with increasing Si doping ratio. The absorption edges of the as-prepared samples got an obvious red shift in which the best one reached 526 nm. N and Si co-doped into the photocatalysts replaced Ti and formed the Ti–O–Si and O–Ti–N link-ages. The photocatalysts modified by H 2 O 2 were well dispersed and changed the molecular structure. The degradation effect of the used Si doped photocatalysts was better than for undoped photocatalysts, and the H 2 O 2 modification could not further enhance the photocatalytic activity for N–Si doped TiO 2 . For the photodegradation of phenol, the optimal molar ratio of Si/Ti and the calcination temperature was 1:4 and 650 °C, respectively. For the optimal photocatalyst, the molar ratios of O/Ti, N/Ti, and Si/Ti were 0.54, 0.19, 0.29, and the phenol removed 94.4 % in 6 h under solar light. The reusability of N–Si co-doped TiO 2 was relatively good.