Preparation of Plate‐Like Sodium Niobate Particles by Hydrothermal Method

Abstract

Sodium niobate NaNbO3 hydrate (NN‐hydrate) particles with a plate‐like morphology were prepared at 140°C for 2 h in 12 mol/L of NaOH by the hydrothermal method. Bar‐like Na8Nb6O19·13H2O particles were synthesized at as low as 100°C for 2 h. This work demonstrates that by carefully optimizing the reaction condition, we can selectively fabricate niobate structures, including the bar‐like, plate‐like, fibers and cube particles through a direct reaction between NaOH solution and Nb2O5. It was found that Nb6O198− formed was an important premise for formation of the NN‐hydrate, and lower [OH–] was not favorable in preparing the NN‐hydrate as there was an optimum [OH−]. Through researching effects of the reaction temperature, time, concentration of NaOH, and content of Nb2O5 on the NN‐hydrate structure and evolution, the formation mechanism from solid reactants to the intermediate were investigated. After calcining at 800°C, the synthesized NN‐hydrate particles made a phase almost transform to the perovskite NaNbO3, and the morphology of these calcined particles was still plate‐like.