Boron-doped TiO2: Characteristics and photoactivity under visible light

Boron-doped TiO2 was prepared by the sol-gel method and by grinding TiO2 powder with a boron compounds (boric acid and boric acid triethyl ester followed by calcinations at temperature range 200 to 600°C. Three types of pristine TiO2: ST-01 (Ishihara Sangyo Ltd., Japan; 300 m2/g), P25 (Degussa, Germany, 50 m2/g), A11 (Police S.A., Poland 12 m2/g) were used in grinding procedure. The photocatalytic activity of obtained powders in visible light was estimated by measuring the decomposition rate of phenol (0.21 mmol/dm3) in an aqueous solution. The photocatalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS), UV-VIS absorption and BET surface area measurements. The best photoactivity under visible light was observed for B-TiO2 modified with 2 wt% of boron prepared by grinding ST-01 with dopant followed by calcinations at 400°C. This photocatalyst contains 16.9 at.% of carbon and 6.6 at.% of boron in surface layer and its surface area is 192 m2/g.