Photocatalytic Properties of Nitrogen-Doped Bi₁₂TiO₂₀Synthesized by Urea Addition Sol-Gel Method

Undoped and nitrogen-doped Bi12TiO20materials were synthesized by urea addition sol-gel method. By adding urea, undoped, and N-doped gel-type precursors were synthesized by low-temperature dehydrolyzation. Nitrogen-doped and undoped nanocrystalline Bi12TiO20were prepared by annealing at 600∘C for 30 minutes. From UV-Vis absorption and diffuse reflection spectrum, the absorbing band shifted from 420 to 500 nm by nitrogen doping. The bonds of Ti–N and N–O were identified by XPS spectra from the prepared materials, and the enhancement of visible light absorption was attributed to nitrogen's substitution of oxygen. Photocatalytic properties of prepared materials were characterized by the decomposition of Rhodamine B illuminated by whole spectra of 300 W Xe light. The photocatalystBi12TiO20−yNy(y=0.03) with N/(N+O) mole ratio about 3% shows better performance than that of heavily dopedBi12TiO20−zNz(z=0.06), undoped Bi12TiO20, and light-dopedBi12TiO20−xNx(x=0.01) photocatalysts due to its better crystalline morphology.