Macroscopic TiO_2-SiO_2 porous beads: Efficient photocatalysts with enhanced reusability for the degradation of pollutants

摘要

A series of TiO_2-SiO_2 photocatalysts in the shape of macroscopic spherical beads (300-500 lm) with highly porous structure and different amount of TiO_2 as active phase was synthesized using a polymeric bead-shaped resin as template. The materials were characterized by a combination of techniques (SEM, TEM, XRD, N_2-physisorption, UV-Vis and FTIR spectroscopy) to correlate their physicochemical properties with their photocatalytic activity in the degradation of phenol and methylene blue under UV irradiation. The innovative shape of these photocatalysts allows straightforward separation and recycling of the material without centrifugation or filtration steps, thus circumventing one of the major issues of TiO_2 in powder form. The optimum activity of the bead-shaped photocatalysts is determined by a balance between high specific surface area and TiO_2 content. The most active among the synthesized TiO_2-SiO_2 porous bead materials showed higher photocatalytic turnover compared to P25 TiO_2.