Hydrothermal synthesis of sodium niobate with controllable shape and structure

We describe the synthesis of hexagonal NaNbO₃ by mixing reactants at high temperature under hydrothermal conditions. The morphological and structural evolution of crystalline NaNbO₃ 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 Na₈Nb₆O₁₉·nH₂O bars, microporous monoclinic Na₂Nb₂O₆· nH₂O fibers, self-assembled dandelion-like Na₂Nb ₂O₆·nH₂O structures, and octahedral-shaped hexagonal NaNbO₃ have been prepared. The present synthetic strategy enables us to tune the morphologies and structures of the niobate products by controlling the reaction kinetics.