Self-assembly and formation mechanism of single-crystal SrTiO3 nanosheets via solvothermal route with ethylene glycol as reaction medium

Magnetite Fe3O4 nanoparticles and hematite α-Fe2O3 uniform oblique hexagonal microdisks, drum-like particles and spindles and their magnetic properties

“…Nonetheless, EG is an organic solvent with two hydroxyls in the molecular structure and easily adsorbs on the solid surface by hydrogen bonding. Many experiments have demonstrated that the adsorption of organic modifiers strongly affects the crystallization and growth [24][25][26][27][28][29]. In the present experiment, the adsorption of EG makes the hematite α-Fe 2 O 3 crystals evolved from oblique hexagonal microdisks, drum-like particles and spindles with the EG/water volume ratio changing from 30:10 to 26:14 and 20:20.…”

“…In consequence, in the present experiment at the EG/water volume ratio of 40:0 and 35:5 the formed iron oxide species are composed of Fe 3 O 4 and crystallize to magnetite Fe 3 O 4 nanoparticles (Fig.1a-b and Fig.2a-b). Otherwise, it is known that the presence of trace water involved in the feedstock is essential for the metal oxide crystals derived from the metal hydroxides under the solvothermal conditions [25,28,33]. Whereas the volume fraction of the involved water in the feedstock is very small, the formed Fe 3 O 4 species located in the water accumulate to of high concentration.…”

“…Whereas the morphology of the hematite α-Fe 2 O 3 crystals evolves from the oblique hexagonal microdisks to drum-like particles and spindles with EG/water volume ratio changing from 30:10 to 26:14 and 20:20, it can be inferred that the further addition of water in the hydrothermal system makes the equilibrium disturbed. In our previous researching work, it has demonstrated that the water involved in the solvothermal system plays an important role in the formation of the SrTiO 3 nanosheets [25]. Because the volume fraction of water is very low in the solvothermal system, the local concentration of the formed SrTiO 3 species in the water is very high.…”

“…Thus, same as the ethanol, EG easily adsorbs on the surfaces of the crystals by hydrogen-bonding to alter the nucleation and crystal growth behavior. In our more recent works, single-crystalline SrTiO 3 nanosheets [25] and monodispersed LiFePO 4 nanoparticles [29] have been hydrothermally achieved with EG as reaction medium solvent in the presence of trace water. In the present work, we propose a facile and simple hydrothermal reaction route to realize the shape-controlled synthesis of α-Fe 2 O 3 crystals from oblique hexagonal microdisks to drum-like particles and spindles by simply tuning the volume ratio of EG and water in the used reaction medium solvent.…”

NaCl–H2O-assisted preparation of SrTiO3 nanoparticles by solid state reaction at low temperature

“…[5][6][7][8][9][10][11] Recently, a variety of SrTiO 3 nanoparticles with specific morphologies (e.g., nanocuboids, nanospheres, nanoparticles, nanosheets, nanowires, nanotubes, and microscale superstructures) have been prepared via high-temperature solidstate reaction, microemulsion, molten salt methods, hydrothermal or solvothermal methods, sol-gel methods, etc. [12][13][14][15][16][17][18][19] However, these methods suffer several problems associated with the environmental load and economical performance. Hydrothermal/solvothermal growth, sol-gel process, and precipitation have several disadvantages such as expensiveness of equipments and reagents, toxicity of the solvents, and complexity of the processes.…”