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Synthesis of Solids
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
The third method was sol–gel synthesis. In one reported method, barium acetate dissolved in acetic acid and titanium butoxide (Ti(OC4H9)4) in glacial acetic acid and absolute ethanol were mixed to form a gel. The gel was heated at 120°C for 8 hours. The resulting dried gel was heated at 500°C for 2 hours. Overall, this process produces more carbon dioxide per molecule of barium salt and so more waste product than the first method (Principle 1). A lower percentage of the starting atoms is found in the product (Principle 2). Barium acetate is toxic if swallowed or inhaled. Titanium butoxide is an irritant for eyes, skin, and respiratory and digestive tracts. In addition glacial acetic acid causes severe burns to skin, eyes, and respiratory and digestive tracts. Absolute alcohol is toxic and irritating to skin and eyes (Principle 3). The solvents used are thus harmful (Principle 5). The temperature for the gel drying is relatively low and the temperature for the final process is lower than for the previous methods (Principle 6). Glacial acetic acid and absolute alcohol are flammable (Principle 12).
Rapid synthesis of TiO2 nanocrystal in aqueous solution at room temperature
Published in Inorganic and Nano-Metal Chemistry, 2022
To prepare TiO2 nanocrystal, 5 ml of titanium butoxide (Ti(C4H9O)4) was dissolved at room temperature (RT) in 50 ml of distilled water under magnetic stirring, then rapidly 2 g of ammonium persulfate ((NH4)2S2O8) was added to the mixture. A white precipitate appeared immediately when the ammonium persulfate was introduced. The obtained mixture was then further stirred for 10 min at room temperature and after that the white precipitate was recuperated by centrifugation or by filtration technique and finally dried at room temperature overnight. To obtain high crystalline nanomaterial, the precipitate was calcined for 30 min at 400 °C. Indeed, the second benefit of this step is to remove all organic/inorganic byproducts attached to the TiO2 surface which can after that limit and inhibit the photocatalytic activity of the nanomaterial. Table 1 displays a comparative study between the present work and the current dominant methods presented in literature.
Optimization of toluene removal over W-doped TiO2 nano-photocatalyst under visible light irradiation
Published in Environmental Technology, 2018
Ali Poorkarimi, Ayoub Karimi-Jashni, Sirus Javadpour
(1) First, the titanium butoxide were washed twice with deionized water by adding 12.655 g titanium butoxide dropwise to 240 ml of deionized water under vigorous stirring in order to ensure that butanol was released from the reaction and white titanium dioxide particles remained after dewatering by centrifuge. (2) Then, 300 ml of deionized water was added to the prepared dioxide titanium to make a mixture named solution I. (3) In the next step, 30 mg tungstic acid was dissolved in 2 ml H2O2 at 90°C, then 45 ml of H2O2 was added. This mixture is named solution II. (4) Solution II was added slowly to solution I while stirring vigorously for 20 min. Stirring continued for 3 h to obtain an orange viscous solution. (5) The final solution was kept at room temperature to turn to gel completely. (6) The produced gel was oven-dried for 24 h at 80°C and then the completely dried sample was ground into a fine powder. (7) Finally, the powder was transferred into a crucible and heated at a desired calcination temperature (300°C, 400°C, 500°C, 600°C and 700°C) for 2 h.
Thermochemistry and growth mechanism of TiC nanowires synthesized by carbothermal reduction
Published in Inorganic and Nano-Metal Chemistry, 2020
Xiaochun Xie, Guosong Ou, Hongquan Men, Min Jiang, Wenxin Lin, Jianjun Chen
A variety of synthesis techniques have been reported for the synthesis of TiC nanowires, such as, chemical vapor deposition,[21,22] carbothermal reduction,[23–25] templated reaction,[26,27] chemical solution deposition,[28] and modified traditional carbothermal reduction method.[29] Among them, carbothermal reduction is a widely-used technique for the synthesis of TiC nanowires. Yuan et al. synthesized TiC nanowires on porous ZrSiO4 substrate via infiltrating and chloride-assisted carbothermal reduction.[15] Xiong et al. reported the large-scale synthesis of TiC whiskers using microcrystalline cellulose as the carbon source by carbothermal reduction.[25,30] Although various synthesized strategies, morphology and the yield of TiC nanowires have been widely investigated by carbothermal reduction,[31–34] the thermodynamic reaction and the growth mechanism of the reaction system are not fully understood. In this work, titanium butoxide (Ti(OC4H9)4) and TiO2 were used as a liquid and solid titanium source, respectively. Carbon black (C) as a carbon source, Metal Ni catalyst and alkali metal halide (NaCl and KCl) as a chlorine precursor were also used. TiC nanowires with a smooth surface about 200 nm–600 nm were obtained by carbothermal reaction at 1473–1673 K in an argon atmosphere. The thermodynamic reactions of Ti-C-O-Cl system were investigated for the first time. Based on our previous thermochemistry and growth mechanism investigation of SiC nanowires,[35] a two-step growth mechanism of TiC nanowires was proposed. Some fundamental data in the work could help to analyze the thermochemistry and growth mechanism of the carbothermal reduction reaction of TiC nanowires in the Ti-C-O-Cl system. Furthermore, the thermochemistry and growth mechanism of TiC nanowires can offer novel theoretical experience for growth process of more crystal, such as, perovskite, metal-organic framework and functional oxides. The theory of crystal growth is benefical to expound the physical properties and chemical performance and optimize the preparation technology.[36–40]