Topochemical synthesis and photocatalytic activity of 3D hierarchical BaTiO₃ microspheres constructed from crystal-axis-oriented nanosheets

Abstract

Novel BaTiO hierarchical porous microspheres were achieved by using HTiO·HO (HTO) hierarchical microspheres as a precursor template via a facile solvothermal method. Interestingly, the BaTiO microspheres were constructed with two-dimensional (2D) nanosheets, which were composed of many order nanocrystals with crystal-axis-orientation. The special hierarchical structure, which is both macroporous and mesoporous, exhibits a large specific surface area and a high total pore volume. The photocatalytic performance of BaTiO hierarchical microspheres for degradation of methyl orange (MO) under UV-light irradiation was tested, its apparent rate being up to 0.10183 min, almost 23 times higher than that for nanoscale BaTiO particles. The attractive photocatalytic properties are considered to benefit from the effective features of hierarchical BaTiO microspheres, such as the ultrathin thickness of nanosheets and their ordered interconnected macro-mesoporous structure and intrinsic photocatalytic activity. This study offers an in situ topochemical conversion route to synthesis of other titanium-based perovskite hierarchical nanostructures, and thus opening the door for the synthesis of other titanium-based functional materials and expanding their potential application.

Solvothermal Synthesis of Anatase TiO2 for the Detoxification of Methyl Orange Dye with Improved Photodegradation Efficiency

“…Since it has a wide surface area and large pore size, the adsorption property improves. [44] These findings show that the morphology, crystallite size, surface area and pore size plays an important role in the photocatalytic degradation of MO.…”

One-Dimensional Piezoelectric BaTiO3 Polycrystal of Topochemical Mesocrystal Conversion from Layered H2Ti4O9·H2O Single Crystal

“…BaTiO 3 (BT) is an important member of the lead-free piezoelectric family of materials and is one of the most promising candidate materials for replacing Pb-based piezoelectric materials owing to BT’s high piezoelectric property and simple preparation process. − At present, BT is mainly prepared by the sol–gel template method, − molten salt reaction, electrospinning, and hydrothermal reactions. , Hydrothermal reactions are a useful method to prepare and design functional inorganic materials. , These reactions are suitable for controlling the target material because they do not require expensive precursors or elaborate apparatuses, and they have the potential to yield high-purity, homogeneous, fine crystalline powders under moderate conditions. , In particular, products obtained from hydrothermal reactions show uniform morphology and small crystal sizes with uniform distribution . Usually, some significant templates with anisotropic morphologies are used as precursors to yield the target with the original framework of the precursor via an in situ topochemical conversion reaction during hydrothermal treatments. ,, Some one- or two-dimensional (1D or 2D) BT crystals can be prepared from protonated titanates, such as H 1.07 Ti 1.73 O 4 ­· n H 2 O, H 2 Ti 4 O 9 ­· n H 2 O, − H 2 Ti 3 O 7 , H 2 Ti 2 O 5 , and other protonated titanates, as precursors with layered structures . These precursors can react with an alkaline earth metal hydroxide to form the BT phase during the hydrothermal process. , Some 2D titanate polycrystals were developed using hydrothermal processes from titanate precursors in our previous works. ,,, Those titanate polycrystals were constructed from oriented nanocrystals and showed single-crystal diffraction points, i.e., they were mesocrystals.…”

“…19 Usually, some significant templates with anisotropic morphologies are used as precursors to yield the target with the original framework of the precursor via an in situ topochemical conversion reaction during hydrothermal treatments. 15,20,21 Some one-or two-dimensional (1D or 2D) BT crystals can be prepared from protonated titanates, such as H 1.07 Ti 26 and other protonated titanates, as precursors with layered structures. 27 These precursors can react with an alkaline earth metal hydroxide to form the BT phase during the hydrothermal process.…”

Hierarchical Porous Batio3 Nano-Hexagons as A Visible Light Photocatalyst

“…Perovskite alkaline earth titanates (ATiO 3 , A= Ca, Ba, Sr) are found to exhibit compelling properties in various applications like photocatalytic degradation of organics, photocatalytic water splitting and photo reduction of carbon dioxide due to their wide band gap, excellent catalytic activity, excellent chemical stability and good biocompatibility. 3 Barium titanate (BaTiO 3 ), a ternary metal titanate perovskite with a high dielectric constant and ferroelectric properties has been extensively investigated. It is also a very important semiconductor under UV light due to its band gap of 3.25 eV and its photocatalytic activity is hampered in visible light.…”