Effect of Synthesis Conditions on Crystal Morphology and Layer Thickness of Nanostructured Sodium Niobate Supported on Metallic Substrate

Abstract

Sodium niobate presents numerous interesting properties for technological application and can be produced in nanometric structures if synthesized by alkali hydrothermal route. Although the influence of synthesis conditions on the product morphology and crystal structure has been well explored for niobates synthesized from the powder of niobium oxide, the synthesis on metallic niobium platelets is not completely understood. Therefore, the present study seeks to correlate the synthesis' variables, of alkali hydrothermal route, to morphology and thickness of sodium niobate nanowire layer supported on niobium platelets. An experimental design was planned to evaluate whether temperature, alkali solution concentration, and reactional duration influence on the produced materials. The morphology of 1D niobates produced was investigated by scanning, while crystal structure was analyzed by X-ray diffraction. The cross sections of 1D sodium niobate layers were cut with a focused ion beam, and their thickness was quantified by scanning electron microscopy images. It was concluded that all chosen variables influenced the thickness of the sodium niobate layer, and a model describing the layer thickness with the chosen variables was proposed. A morphology change from nanowires at the mildest synthesis conditions to nanoribbons at the most severe ones was observed (see Supplementary Material for graphical abstract).