Synthesis and photocatalytic activity of boron-doped TiO2 in aqueous suspensions under UV-A irradiation

摘要

Boron-doped TiO2 photocatalysts were synthesized employing a sol-gel method. Boric acid wasnused as the boron source and titanium tetra-isopropoxide as the TiO2 precursor, both dissolvednin isopropanol. Nominal boron to titanium atomic ratios were in the range 0 to 4%. After thenhydrolysis step, two different procedures for the recovery of TiO2 were followed, based onneither centrifugation of the resulting reaction mixture or evaporation of the solvent undernreduced pressure, both followed by a subsequent calcination step performed at 400 or 5008C.nThe photocatalytic efficiency of the synthesized photocatalysts was assessed by measuring thenphotocatalytic mineralization of dichloroacetic acid in aqueous suspensions under UV-Anirradiation and it was compared to the corresponding efficiency of the commercial DegussanP 25 TiO2. Photocatalytic efficiency of the synthesized catalysts was higher for the boron-dopednTiO2 synthesized at 2% boron to titanium nominal atomic ratio, centrifuged after the hydrolysisnstep followed by calcinations at 4008C. However, all photocatalysts synthesized in this worknshowed lower photocatalytic activity than Degussa P 25 TiO2, thus highlighting the need ofnfurther improvements of the proposed method.