Revealing the Role of the Intermediates during the Synthesis of BaTi₅O₁₁

Abstract

BaTi5O11 has been extensively studied because of their microwave dielectrics properties. Traditionally, it is difficult to achieve this material as single-phase. Here, we report an effective method to obtain BaTi5O11 powder with nanometerscale crystals, by solid-state reaction at moderate temperatures and using as precursors nanostructured particles consisting of BaTiO3 and TiO2. The main advantage is the intimate contact between the BaTiO3 and TiO2 that ensure, when the solid-state reaction takes place, the formation of complex solid compounds from three or more constituents. The formation mechanism of BaTi5O11 has been studied as a function of both the thermal treatment and the time reaction. The reaction was monitored by Raman spectroscopy combined with Confocal microscopy, the aim of this characterization technique is to provide the description of the general strategy and design principles to obtain BaTi5O11 powder. Consequently, this work is a challenging task for the compositional and structural study of complex inorganic nanoparticles.

Nano Anatase TiO2 Quasi-Core–Shell Homophase Junction Induced by a Ti3+ Concentration Difference for Highly Efficient Hydrogen Evolution

“…38 The self-doping Ti 3+ in the interior of TiO 2 can induce vacancy-related electronic states under the CBM from Ti 3+ 3d 1 , leading to redshift of the CBM. 11,47 In the meantime, the existence of high Ti 3+ concentration in the interior could break the lattice periodicity and octahedral symmetry of TiO 6 , inducing the blueshift of VBM from O 2p 6 . 47 Therefore, the interior region of TiO 2 exhibits considerable band bending of both the conduction band (CB) and valence band (VB), showing a narrower bandgap at the quasi-core region compared with the quasi-shell region.…”

“…Semiconductor photocatalysis has been widely investigated for energy conversion and environmental purification due to the direct utilization of solar energy. − Among all kinds of semiconductors, TiO 2 is well-known to be one of the most attractive photocatalysts owing to its cheapness, stability, and high photoreactivity. − However, the low efficiency of the charge separation and the wide band gap (∼3.2 eV) hamper the practical applications of TiO 2 . − Various efforts have been made to facilitate the separation of photogenerated electron–hole pairs and to narrow the band gap of TiO 2 for promoting photocatalytic activity. − …”