Iranian Journal of Materials Science and Engineering

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Abstract:In the present research, SiO2–TiO2 nanostructure films were successfully prepared on windshields using the sol–gel technique for photocatalytic applications. To prevent the thermal diffusion of the sodium ions from the glass to TiO2 films, the SiO2 layer was pre-coated on the glass by the sol–gel method. The substrates were dipped in the sol and withdrawn with the speed of 6cm/min-1 to make a gel coating film. The coated films were dried for 2 days at 27 °C to allow slow solvent evaporation and condensation reactions due to rapid sol–gel reaction of Titania precursor. Then, the films were annealed at 100 °C for 30min and at the final temperature (500, 700 °C) for 30 min continuously. The structure and surface morphology properties, which are as a function of annealing temperature, have been studied by SEM FE-SEM and XRD. The FE-SEM surface morphology results indicate that the particle size increases from 19 to 42 nm by increasing the annealing temperature from 500 °C to 700 °C. Likewise, XRD illustrate the crystal anatase and rutile as main phases for TiO2-SiO2 films annealed at 500 °C and 700 °C respectively. This procedure resulted in transparent, crack-free SiO2–TiO2 films.

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Silicon carbide (SiC) is one of the most important silicon-based compounds, owing to its favorable physical, chemical, and biological properties, and is widely employed in various fields such as electronics, chemical industries, and quantum computing. Several methods have been reported for synthesizing SiC nanoparticles, including chemical vapor deposition (CVD), hydrothermal synthesis, carbothermal reduction, and sol–gel processing. Among these, the sol–gel method has attracted significant attention due to its high yield, process controllability, biocompatibility, accessibility of precursors, and ability to produce nanoparticles. In this study, SiC nanosized powders were synthesized through the sol–gel route combined with carbothermal reduction, using tetraethyl orthosilicate (C₂H₅)₄SiO₄) and sucrose (C₁₁H₂₂O₁₁) as the silicon and carbon sources, respectively. The silica/sucrose composite was subjected to carbothermal reduction under an argon atmosphere at a pressure of 10 mTorr in a vacuum furnace at 1350°C for 3 h. The structural properties of the synthesized SiC nanopowders were analyzed using X-ray diffraction (XRD), while their optical characteristics were investigated through FTIR, diffuse reflectance spectroscopy (DRS), and photoluminescence (PL). This work demonstrates a greener, lower-temperature route to phase-controlled SiC nanoparticles with optically active vacancy centers.