Synthesis and characterisation of metastable phase Bi20TiO32 nanosheets

Bi20TiO32 was synthesised successfully by sol–gel and ultrasonic assisted surface impregnation methods using tetrabutyl titanate as titanium source and bismuth nitrate as bismuth source. The samples were characterised by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-vis diffuse reflectance spectrocopy (DRS) and so on. In order to evaluate its photocatalytic denitrogenation performance, simulate oil containing a certain concentration of pyridine was used as the target. The results showed that the synthesized Bi20TiO32 was a kind of tetragonal crystal system of Bi–Ti oxide in metastable phase, with nanosheet size of about 16 nm and band gap of 2·9 eV, which can absorb the light ranging from the UV to 500 nm wavelength. The activity of photocatalytic degradation of 0·05 mg photocatalyst on 50 mL simulated oil (pyridine containing 100 ug g−1) was up to 86·0% under the irradiation of visible light above 420 nm wavelength for 150 min.