Preparation and Photocatalytical Performance of TiO<SUB>2</SUB>:SiO<SUB>2</SUB> Nanocomposites Produced by the Polymeric Precursors Method

Abstract

Anatase TiO2 is a promising photocatalyst due to its chemical stability, non-toxic characteristics, notable UV light absorption as well as photo-corrosion resistance and oxidative properties. Surface area and TiO2 dispersion quality are important factors that affect photoactivity of TiO2:SiO2 nanocomposites. In order to improve these factors, TiO2 nanoparticles were immobilized on mesoporous silica substrate through the polymeric precursors method, obtaining the nanocomposites in a simple routine. The TiO2 resin was synthesized by the polymeric precursors method and different resin thickness (0.5; 1.0; 2.0; 3.5; 5.0 nm) on silica were synthesized by calcination during 4 hours at 450 degrees C in pH 1.5. The selected pH for immobilization ensured adhesion of TiO2 nanoparticles onto the silica substrate surface. X-Ray Diffraction patterns indicate that all samples were predominantly anatase phase and immobilization improved surface area. Ametryn kinetic evaluation presents better results for SAM 3.5 and SAM 0.5. The results show that difference in TiO2 loading, surface area and crystallinity of samples are factors that influence photocatalytic efficiency.

Preparation, characterization and application of phase-pure anatase and rutile TiO2 nanoparticles by new green route

“…RhB photocatalytic degradation under UV-C illumination for TiO 2 synthesized materials presents similar behavior to other TiO 2 materials synthesized by different methods [27][28][29][30]. The photocatalytic degradation mechanism of RhB is influenced by a dye-sensitizing mechanism due to the color aspect of RhB, and this could generally increase effective degradation: as such its k′ values are expected to be higher.…”

Vanadium pentoxide 1-D nanostructures applied to dye removal from aqueous systems by coupling adsorption and visible-light photodegradation

“…48 Then, in order to answer which atom (S or N) is responsible for interaction/binding of MB dye at adsorbent surface, the solid state 13 C NMR spectra were acquired for the MB pure and SAM02 aer adsorption experiments onto SAM02 sample. MB molecule showed 7 carbons with different chemistry environment in 13 C NMR spectra (see identication at Fig. 7a), however, the carbons identied how 2 and 3, 5 and 6, respectively, showed a slight shi between them.…”

“…The ethanol was chosen due to its better interaction with MB dye when compared to water and other solvents. 39 To check the presence of MB molecules adsorbed onto the as-synthesized nanostructures and their stability, the samples were separated through centrifugation, and then characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, XRD patterns and high-resolution 13 C nuclear magnetic resonance (NMR). For this analysis, we used the powders from MB solution with initial concentration of 50 mg L À1 .…”

“…Spectra of solid-state 13 C NMR with variable amplitude, cross-polarization and magic angle spinning (VACP/MAS) were obtained in a spectrometer Bruker (Avance III HD) operating at a frequency of 400 MHz for 1H and 100.59 MHz for 13 C, under the following experimental conditions: 10 kHz spinning speed, with the contact time of 45 ms and relaxation time of 5 s. About 50 mg of SAM02 + MB and MB pure were packed in a 5 mm cylindrical zirconium rotor with Kel-F end-caps. The chemical shi values were calibrated using tetramethylsilane as a reference.…”

“…8,10 Previous studies have focused on composites containing adsorbent and photocatalytic materials. [10][11][12][13] Composites of TiO 2 with activated carbon 10 and TiO 2 with SiO 2 13 have presented higher pollutant removal efficiencies compared with the isolated phases. On the other hand, additional studies have shown the application of one phase, which acts as an adsorbent and photocatalyst concomitantly.…”