Rationalization of Hydrothermal Synthesis of NaNbO3 by Rapid in Situ Time-Resolved Synchrotron X-ray Diffraction

Abstract

In situ monitoring of the formation of crystalline phases during conventional hydrothermal synthesis is experimentally challenging. Here, we report an in situ time-resolved synchrotron X-ray diffraction study during hydrothermal synthesis of NaNbO3 using a high-pressure custom-made capillary cell penetrable to X-rays. The high time resolution (0.1 s) revealed a sequence of transient intermediate phases, including several unknown phases, before the final perovskite NaNbO3 was formed. These new findings highlight the complexity of the hydrothermal synthesis of NaNbO3 and demonstrate the potential for obtaining in-depth knowledge of the reactions taking place by time-resolved in situ X-ray diffraction.