The Morphology Control of BaTiO₃ Particles Synthesized in Water and a Water/Ethanol Solvent

Abstract

The experimental conditions for the growth of shape-controlled BaTiO 3 particles in NaOH and Ba(NO 3 ) 2 aqueous and water/ ethanol solutions using various TiO 2 -containing precursors were studied at 80°C-100°C. The different chemistries and physical characteristics of the precursors resulted in different BaTiO 3 formation rates and morphologies . Nanocrystalline anatase led to irregularly shaped BaTiO 3 particles, whereas star-like, single-crystalline BaTiO 3 particles grew from aerogel TiO 2 and sodium titanate (NT) belts in alkaline aqueous solutions. With the addition of ethanol, the star-like BaTiO 3 particles changed to square-like, the size of which decreased with an increase in the ethanol content. The electron microscopy observations supported a dissolution-precipitation mechanism as the primary reaction mechanism for the formation of BaTiO 3 nanocrystals, which further aggregated into single-crystalline star-or square-like particles by oriented attachment. The modification in the water solution with ethanol is believed to influence both the nucleation and aggregation process and consequently influence the particle shape and size.M. Parans Paranthaman-contributing editor Manuscript No. 33061.

Hydrothermal conditions for the formation of tetragonal BaTiO3 particles from potassium titanate and barium salt

“…The current tendency for the miniaturization of electronic components, together with the development of nanotechnology, has increased the interest in preparing and investigating defined one-(1D) and two-dimensional (2D) nanoparticles of ferroelectric perovskites, including tetragonal BaTiO 3 . Among the low-temperature methods, hydrothermal and solvothermal syntheses are considered to be the most successful approaches for controlling the shape of BaTiO 3 particles [1,2]. These methods, which under moderate conditions (T≤240°C) usually yield pseudo-cubic particles with a partially controllable shape, still represent a major research challenge for the preparation of highly tetragonal, non-aggregated BaTiO 3 particles with a defined shape [2,3].…”

“…Among the low-temperature methods, hydrothermal and solvothermal syntheses are considered to be the most successful approaches for controlling the shape of BaTiO 3 particles [1,2]. These methods, which under moderate conditions (T≤240°C) usually yield pseudo-cubic particles with a partially controllable shape, still represent a major research challenge for the preparation of highly tetragonal, non-aggregated BaTiO 3 particles with a defined shape [2,3]. In recent decades, considerable research has focused on the conditions for the formation of tetragonal BaTiO 3 at hydrothermal temperatures of 200-240°C.…”

“…The mechanism for BaTiO 3 crystallization under hydrothermal conditions has been well studied [2,4,13,14]. Two generally accepted explanations for BaTiO 3 formation have been proposed in the literature: (a) a dissolution-precipitation and (b) an in-situ transformation.…”

“…The formation of BaTiO 3 has been mostly studied from anatase, amorphous TiO 2 , Na 2 Ti 3 O 7 nanotubes and nanowires, TiCl 4 and Ti(OiPr) 4 [1][2][3][4][5][6][7][8][9][10][12][13][14][15][16]. Despite a promising one-dimensional structure, expectations that the K2T6 nanostructure (nanowires, nanorods) could serve as a good template for the preparation of BaTiO 3 with a preserved precursor shape [21].…”

Hydrothermal synthesis of tetragonal barium titanate nanopowders under moderate conditions

“…In recent years, hydrothermal method has been proved to be a valid route to prepare BaTiO 3 powders with a controllable shape and a narrow particle size distribution [10,11]. Generally, when the hydrothermal temperature is lower than 240°C, the as-prepared BaTiO 3 powders have paraelectric cubic structure and particle size of less than 0.1 µm.…”