Synthesis of complex niobate nanostructures via molten-salt reaction: Effect of ZrO2 on product morphology

• Small amount of ZrO2 impurity changed the morphology of products.
• Nanoscale niobate rods and ribbons were synthesized and characterized.
• A possibility was found to control the morphology of KNN nanostructures from rods to ribbons.

Lead-free (K, Na)NbO3 (KNN) one-dimensional (1-D) piezoelectric nanostructures can be synthesized by the facile method based on molten-salt reaction, for which the intermediate niobate-based products play a key role as the precursors of final KNN products. In this work, it was found that the morphology and structure of K6Nb10.8O30 precursors were sensitive to ZrO2 impurity introduced during synthesis process. The result was further confirmed by an experiment with intentional ZrO2 addition, which assisted the product morphology change from rods to ribbons. The present study also suggested a simple method to control the morphology of KNN nanostructures inherited from the niobate-based precursors.