Preparation of Nano-TiO₂ by a Surfactant-Free Microemulsion–Hydrothermal Method and Its Photocatalytic Activity

Abstract

The TiO 2 nanoparticles with high photocatalytic activity were prepared by the surfactant-free microemulsion (SFME)−hydrothermal method at lower temperatures using oil-in-water SFME systems as templates. The phase diagram of the SFME ethyl acetate (EA)/propan-2-ol/water was determined by electrical conductivity and UV−visible spectroscopy. The synthesized TiO 2 nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, and N 2 adsorption− desorption techniques. They were all assigned to the anatase phase and showed type IV adsorption−desorption isotherms with type H2 hysteresis loops. As the EA content (f O ) of the SFME decreases, the Brunauer−Emmett−Teller (BET) specific surface area (S BET ) of the TiO 2 nanoparticles increases. This results in an increase in the photocatalytic activity of the TiO 2 nanoparticles. With an increase in temperature, the photocatalytic activity of the TiO 2 nanoparticles increases significantly, whereas the S BET values decrease and the crystal size increases. Under the same conditions, the degradation rate of the TiO 2 prepared at 190 °C reaches 97%, which is significantly higher than that of Degussa P-25 (66%). This may be due to the use of the SFME system to synthesize the TiO 2 nanoparticles, which avoids the blocking effects of surfactant molecules on the active sites of the nanoparticles.

Improving platinum dispersion on SBA-15 by titania addition

“…SBA-15 and corresponding Ti-modified solids had type IV N 2 adsorption isotherms (Figure 1(a)) with H1 hysteresis as defined by the International Union of Pure and Applied Chemistry (IUPAC) (Sing et al, 1985) those isotherm profiles being typical of mesostructured matrices containing cylindrical pores of uniform section (Leofanti et al, 1998). Hysthereses loops shape was progressively modified to H 2 -type probably by influence of titania segregated domains (Cui et al, 2019). Textural characteristics of various prepared solids (mixed supports and corresponding Pt-impregnated materials) are shown in Tables 1 and 2.…”

Design of functional nanoparticles by microfluidic platforms as advanced drug delivery systems for cancer therapy

“…17 For all these reasons, the NP fabrication methods represent an important tool for the reproducibility of biological assays. In particular, there are a variety of NP synthetic conventional methods such as nanoprecipitation, 18 solvent evaporation, 19,20 microemulsions, 21 sol-gel, 22,23 emulsion polymerization, 24 his master's degree in Biology cum laude from University la Sapienza (Rome) in 1995 and he did research activity as a research fellow at the same university in the field of genetic engineering and chemistry of fermentation processes. Since 2010 he has been a Production and R&D manager at Altergon ITALIA S.r.l and his research interests are related to fermentation plants of injectable grade polysaccharides and development of microneedles and microfluidics technology on the pilot scale.…”

“…17 For all these reasons, the NP fabrication methods represent an important tool for the reproducibility of biological assays. In particular, there are a variety of NP synthetic conventional methods such as nanoprecipitation, 18 solvent evaporation, 19,20 microemulsions, 21 sol–gel, 22,23 emulsion polymerization, 24 layer-by-layer self-assembly, 25 thin-film hydration, 26 bulk mixing by extrusion, 27 pipette mixing, 28 electrodeposition and thermal decomposition. 29,30 In these methods, the formation of the NPs can be divided into three stages, a) nucleation, b) growth and c) aggregation, which occur concurrently leading to some differences, in terms of physicochemical properties, from batch-to-batch of synthesized NPs.…”

CO2-Responsive Hydrophobic Deep Eutectic Solvent Based on Surfactant-Free Microemulsion-Mediated Synthesis of BaF2 Nanoparticles

“…This process requires high temperature and corrosion-resistant equipment. Although microemulsion droplets can be applied as a stencil for the synthesis of nanoparticles, they are still likely to suffer from recovery problems. , Therefore, an adjustable microemulsion is urgently needed to prepare and recover BaF 2 .…”