Hydrothermal synthesis of sodium niobate with controllable shape and structure

Abstract

We describe the synthesis of hexagonal NaNbO 3 by mixing reactants at high temperature under hydrothermal conditions. The morphological and structural evolution of crystalline NaNbO 3 was studied in detail using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, high-resolution transmission electron microscopy, and Raman techniques. A variety of products in the form of irregular Na 8 Nb 6 O 19 $nH 2 O bars, microporous monoclinic Na 2 Nb 2 O 6 $nH 2 O fibers, self-assembled dandelion-like Na 2 Nb 2 O 6 $nH 2 O structures, and octahedral-shaped hexagonal NaNbO 3 have been prepared. The present synthetic strategy enables us to tune the morphologies and structures of the niobate products by controlling the reaction kinetics.

Investigation of local structure effect and X-ray absorption characteristics (EXAFS) of Fe (Ti) K-edge on photocatalyst properties of SrTi(1−x)FexO(3−δ)

“…At the K-edge X-ray excitation, electrons of 1s orbitals are transferred to partially occupied or empty states (XANES region) nearby the Fermi level (3d and 4p-related orbitals), at higher energy X-rays electrons jump to the continuum (EXAFS region, where the outgoing electrons are scattered by neighboring atoms) [55e57]. Structural data on cubic perovskite ABO 3 (A ¼ Sr, B ¼ Ti, Fe) suggest that 6 oxygen atoms are observed in the cation first coordination sphere in position B [58]. The second and third coordination spheres contain 8 strontium atoms and 6 metal atoms, respectively [59].…”

One‐Step Surfactant‐Free Hydrothermal Synthesis of Platelike Sodium Niobate Template Powders

“…19 The morphology of as-synthesized rhombohedral NaNbO 3 is shown in Fig. 19 The morphology of as-synthesized rhombohedral NaNbO 3 is shown in Fig.…”

“…In general, the stable phase at room temperature is orthorhombic NaNbO 3, and the synthesis of rhombohedral NaNbO 3 has rarely been reported. 19 The morphology of as-synthesized rhombohedral NaNbO 3 is shown in Fig. 2.…”

Preparation and photocatalytic activity of triangular pyramid NaNbO 3

“…From the viewpoint of morphology, nanostructured NaNbO 3 , such as nanowire, nanocube and nanoplate, were synthesized and investigated for the photocatalytic activity, revealing that the morphology control will bring the enhanced photocatalytic activity [11,12,15,[19][20][21]. Hydrothermal method is a good way to prepare the sample with special morphologies, and free substrate was usual in this method [22,23]. However, some single crystal substrate could be used as the substrate to grow the sample exposed certain facets [24,25].…”