Boron-doped TiO2 photocatalysts were synthesized employing a sol-gel method. Boric acid was used as the boron source and titanium tetra-isopropoxide as the TiO2 precursor, both dissolved in isopropanol. Nominal boron to titanium atomic ratios were in the range 0 to 4%. After the hydrolysis step, two different procedures for the recovery of TiO2 were followed, based on either centrifugation of the resulting reaction mixture or evaporation of the solvent under reduced pressure, both followed by a subsequent calcination step performed at 400 or 500°C. The photocatalytic efficiency of the synthesized photocatalysts was assessed by measuring the photocatalytic mineralization of dichloroacetic acid in aqueous suspensions under UV-A irradiation and it was compared to the corresponding efficiency of the commercial Degussa P 25 TiO2. Photocatalytic efficiency of the synthesized catalysts was higher for the boron-doped TiO2 synthesized at 2% boron to titanium nominal atomic ratio, centrifuged after the hydrolysis step followed by calcinations at 400°C. However, all photocatalysts synthesized in this work showed lower photocatalytic activity than Degussa P 25 TiO2, thus highlighting the need of further improvements of the proposed method.
Keywords: boron-doped TiO2, dichloroacetic acid, photocatalysis, sol-gel