Ultrasonic-Assisted Synthesis, Characterization, and Photocatalytic Application of SiO₂@TiO₂ Core-Shell Nanocomposite Particles

Abstract

In this study, we report the synthesis of SiO2@TiO2 core-shell nanocomposite particles by ultrasound irradiation of a mixture of dispersed SiO2 nanoparticles, titanium-tetra-n-butoxide (TBOT), and ammonia in an ethanol-water solution medium. The resulting core-shell nanocomposite particles were characterized by SEM, TEM, FT-IR, XPS, XRF, zeta potential measurements, XRD, and UV-visible spectroscopy. Results showed that TiO2 nanoparticles coated on the surface of SiO2 were 6–10 nm in size and retained an anatase crystalline phase. Zeta potential measurements confirmed that the surface property of the SiO2 changed after TiO2 coating. SiO2@TiO2 core-shell particles demonstrated better decolorization of methylene blue dye compared to commercial TiO2 in aqueous solution under UV light. After treatment, the catalysts were separated with low-speed centrifugation and successfully reused four times without loss of activity. This study may provide some inspiration for the synthesis of other metal oxide-metal oxide core-shell nanocomposite materials through ultrasound irradiation.

Photocatalysis of nanocomposite titania–natural silica as antibacterial against Staphylococcus aureus and Pseudomonas aeruginosa

“…The role of the addition of SiO 2 is described in Scheme 1. The mechanism of SiO 2 as a photocatalyst supporting material has been described by Bahadur et al (2019) 48 where the excited electrons move from the TiO 2 surface to the SiO 2 surface as electron storage thereby increasing photo-generation for the photocatalyst process. The nanocomposite activity was inuenced by the crystal phase, crystallinity, and particle size.…”

“…47 Furthermore, the antimicrobial activity of SiO 2 was more signicant at the nanoscale size due to the increased surface area. 49 However, SiO 2 showed poor antibacterial activity against S. aureus. The antibacterial activity in this study is in accordance with Erdural et al (2014), 30 who used SiO 2 from synthetic chemicals; hence, this study shows that the use of SiO 2 from natural materials is effective in inactivating bacteria.…”

Facile Fabrication of C–TiO2 Nanocomposites with Enhanced Photocatalytic Activity for Degradation of Tetracycline

“…55−57 On the other hand, compared to pristine TiO 2 , C–TiO 2 -2 nanocomposites showed a lowered ζ-potential value at pH = 4.5 (Figure S5), which means a better dispersion of C–TiO 2 -2 hybrid compared to that of pristine TiO 2 nanoparticles. 58 Cyclic experiments of TC degradation in the presence of C–TiO 2 -2 nanocomposites were carried out to study the stability and reusability of the photocatalyst. As revealed in Figure 7, after five cycles of operation, the photodegradation efficiency of TC did not decrease significantly, which shows that the C–TiO 2 -2 photocatalyst has the advantages of high efficiency, reusability, and good stability and has potential practical application value in wastewater treatment.…”

“…The rate constant of C–TiO 2 -2 is up to 5.69-fold higher than that of the bare TiO 2 . The higher photocatalytic activity of C–TiO 2 -2 was because its two-dimensional porous carbon layer enhanced the light absorption region, inhibited the recombination rate of photoelectrons and holes, and enhanced TC adsorption through the π–π stacking. − On the other hand, compared to pristine TiO 2 , C–TiO 2 -2 nanocomposites showed a lowered ζ-potential value at pH = 4.5 (Figure S5), which means a better dispersion of C–TiO 2 -2 hybrid compared to that of pristine TiO 2 nanoparticles . Cyclic experiments of TC degradation in the presence of C–TiO 2 -2 nanocomposites were carried out to study the stability and reusability of the photocatalyst.…”

Semiconductor Quantum Dots (CdX, X = S, Te, Se) Modify Titanium Dioxide Nanoparticles for Photodynamic Inactivation of Leukemia HL60 Cancer Cells

“…The holes and electrons generated by TiO 2 have excellent oxidation and reduction abilities, respectively, under the ultraviolet light irradiation [9,10]. However, due to the high band gap energy (3.2 eV) of TiO 2 , the visible light response is ineffective and fast recombination of the electron-hole generated on the surface, which limits the PDT efficiency of titanium dioxide in practical application [11,12].…”