Template-Assisted Sol-Gel Synthesis of Nanocrystalline BaTiO3

Nanocrystalline perovskite barium titanate with an average particle size less than similar to 10 nm is produced using sol-gel route involving ligand-assisted templating. BaTiO3 is obtained by the controlled hydrolysis and condensation reaction of barium acetate (Ba(CH3COO)(2)) with titanium tetra chloride (TiCl4) in the reverse micelles of dodecylamine (DDA) which is used as the template. Our attempts to produce mesoporous BaTiO3 have resulted in the formation of nanocrystalline BaTiO3. The synthesis of nanostructured BaTiO3 is carried out using the ligand-assisted templating approach which proceeds through the sol-gel route. Dodecylamine is used as the template. The sol-gel process in general presents inherent advantages because the nanostructure of the desired materials can be controlled together with their porous structure. Ligand-assisted templating approach involves the formation of covalent bond between the inorganic analogue and the template. Ba(CH3COO)(2) and TiCl4 are used as barium-source and titanium-source respectively. The reaction between Ba(CH3COO)(2) and TiCl4 is found to take place deliberately on the pre-assembled species which acts as the template or occurring with in them which in turn will lead to the generation of the desired nanoscale structure (nanopores or nanoparticles)

Synthesis of mesoporous materials based on titanium(IV)oxide and titanium nitride

Nanoparticles of titania were obtained by the controlled hydrolysis of Ti(i-OC3H7)(4) in the reverse micelles of dodecylamine derived from dodecylamine-isopropanol-water solution (water/oil microemulsion). The mesolamellar phase based on titanium nitride (TiN) was obtained by first decomposing TiN atleast partially using the 1:1 solution of acid mixture (HF and HNO3 in the ratio of 9:1) in water and then templating onto the cationic surfactant namely, cetyltrimethylammaniumbromide (abbreviated as CTAB) at 80 degrees C. The synthesis of mesolamellar phase based on TiN involves the charge matched templating approach following the counter-ion mediated pathway. The samples thus obtained were characterized by small angle x-ray diffraction using Cuk(a) radiation, scanning electron microscopy and transmission electron microscopy, which indicated some satisfactory results. (C) 1999 Acta Metallurgica Inc

Nanocrystalline TiO2TiO_2 by three different synthetic approaches: A comparison

A comparison of the efficiency of three different synthetic routes viz. sol–gel method involving templating, mechanochemical synthesis and combustion synthesis for the production of nanostructured $TiO_2$, is reported. In the sol–gel method, nanocrystalline $TiO_2$ is produced when titanium tetraisopropoxide is templated onto dodecylamine which forms the liquid crystalline hexagonal structure and the template is then extracted using 1 : 1 solution of ethanol–hydrochloric acid mixture. Mechanochemical synthesis of nanocrystalline $TiO_2$ involved mechanical illing of stoichiometric amounts of titanium and cupric oxide in a planetary ball mill using stainless steel vial with wear resistant stainless steel balls. Nanocrystalline $TiO_2$ is produced by the combustion reaction involving titanyl nitrate and fuels like glycine and citric acid. Nanostructured $TiO_2$ with an average particle size of $\sim 14 nm$ is produced by the sol–gel method whereas the mechanochemical reaction between titanium and cupric oxide resulted in the formation of nanocrystalline $TiO_2$ with an average particle size of $\sim 20 nm$ after 12 h of milling. On the other hand, combustion synthesis resulted in the formation of nanocrystalline $TiO_2$ with an average particle size of less than $\sim 50 nm$. The microstructures of nanocrystalline $TiO_2$ produced by the above three methods are analysed

Nanocrystalline TiO2TiO_2 by three different synthetic approaches: A comparison

A comparison of the efficiency of three different synthetic routes viz. sol–gel method involving templating, mechanochemical synthesis and combustion synthesis for the production of nanostructured $TiO_2$, is reported. In the sol–gel method, nanocrystalline $TiO_2$ is produced when titanium tetraisopropoxide is templated onto dodecylamine which forms the liquid crystalline hexagonal structure and the template is then extracted using 1 : 1 solution of ethanol–hydrochloric acid mixture. Mechanochemical synthesis of nanocrystalline $TiO_2$ involved mechanical illing of stoichiometric amounts of titanium and cupric oxide in a planetary ball mill using stainless steel vial with wear resistant stainless steel balls. Nanocrystalline $TiO_2$ is produced by the combustion reaction involving titanyl nitrate and fuels like glycine and citric acid. Nanostructured $TiO_2$ with an average particle size of $\sim 14 nm$ is produced by the sol–gel method whereas the mechanochemical reaction between titanium and cupric oxide resulted in the formation of nanocrystalline $TiO_2$ with an average particle size of $\sim 20 nm$ after 12 h of milling. On the other hand, combustion synthesis resulted in the formation of nanocrystalline $TiO_2$ with an average particle size of less than $\sim 50 nm$. The microstructures of nanocrystalline $TiO_2$ produced by the above three methods are analysed

Combustion synthesis of nanostructured barium titanate

The synthesis of nanosize barium titanate by the combustion of redox mixtures containing different Ba-precursors (nitrate, acetate or peroxide) $TiO(NO3)_2$ and fuel (carbohydrazide, glycine or citric acid) was studied. The formation and nanosize nature of barium titanate were confirmed by X ray diffraction and transmission electron microscopy. A high order of porosity was observed as indicated by scanning electron microscopy. The combustion reaction was different depending on the precursor, fuel and the amount of gases liberated. This appears to control the product characteristics and microstructure. The liberation of a large amount of gases results in the product with greater porosit