Synthesis of wrinkled-SiO2-TiO2 for crystal violet photodegradation

KEYLA FUENTES; MARTINEZ RICCI, MARIA LUZ; SARA A. BILMES; MARIA CLAUDIA MARCHI; ROBERTO CANDAL; AMANDA PASQUOTO PERISSINOTTO; UBIRAJARA PEREIRA RODRIGUES-FILHO

Congreso; SBPMat-XVI Brazilian MRS Meeting; 2017

Our work group has recently reported that TiO2 nanoparticles supported on non-porous SiO2 spheres exhibit increased activity in the photocatalytic degradation of crystal violet due to a light confinement effect, highly favored by the good contrast of refractive indices. On the other hand, mesoporous silica has been widely used in adsorption processes due to their high specific area and pore volume. In this regard, this work focus in the synthesis of core-shell particles using wrinkled SiO2 spheres (W-SiO2@TiO2) for the crystal violet photodegradation under UV light. The porous SiO2 spheres were prepared using the bicontinuous microemulsion method, while the incorporation of TiO2 was carried out by hydrothermal treatment. To evaluate the influence of titania location into the porous net, surfactant used as silica pore template was not removed in some cases (not washed systems). We found that the presence of surfactant in the unwashed spheres would block the access of the TiO2 precursor to the internal porous net and favoring the formation of a layer. Whereas, the washed SiO2 spheres does not fully charge with the TiO2 nominal content and it crystallizes inside the silica pores. The exposed area of TiO2 is higher in the first case and consequently the adsorption of the contaminant and its photodegradation is greater. The comparison with non-porous systems reveals that the core@shell particle prepared with not washed silica spheres results more efficient for dye removal.