Rationalization of Hydrothermal Synthesis of NaNbO<sub>3</sub> by Rapid <i>in Situ</i> Time-Resolved Synchrotron X-ray Diffraction

Skjærvø, Susanne Linn; Wells, Kristin Høydalsvik; Sommer, Sanna; Vu, Tuong Dan; Tolchard, Julian R.; Beek, Wouter van; Grande, Tor; Iversen, Bo B.; Einarsrud, Mari Ann

doi:10.1021/acs.cgd.7b01192

Cited by 20 publications

(18 citation statements)

References 22 publications

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“…The experiments were conducted in transmission mode, using the PILATUS@SNBL platform [23]. The experimental setup is described elsewhere [18,24,25]. In short, it consists of a single crystal sapphire capillary (1.15 ± 0.1 mm outer and 0.8 ± 0.08 mm inner diameter) that is pressurized with a high-pressure liquid chromatography (HPLC) pump and heated with a high temperature heat blower with nitrogen flow.…”

Section: Characterizationmentioning

confidence: 99%

Facile Low Temperature Hydrothermal Synthesis of BaTiO3 Nanoparticles Studied by In Situ X-ray Diffraction

et al. 2018

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Ferroelectric materials are crucial for today's technological society and nanostructured ferroelectric materials are important for the downscaling of devices. Controlled and reproducible synthesis of these materials are, therefore, of immense importance. Hydrothermal synthesis is a well-established synthesis route, with a large parameter space for optimization, but a better understanding of nucleation and growth mechanisms is needed for full utilization and control. Here we use in situ X-ray diffraction to follow the nucleation and growth of BaTiO 3 formed by hydrothermal synthesis using two different titanium precursors, an amorphous titania precipitate slurry and a Ti-citric acid complex solution. Sequential Rietveld refinement was used to extract the time dependency of lattice parameters, crystallite size, strain, and atomic displacement parameters. Phase pure BaTiO 3 nanoparticles, 10-15 nm in size, were successfully synthesized at different temperatures (100, 125, and 150 • C) from both precursors after reaction times, ranging from a few seconds to several hours. The two precursors resulted in phase pure BaTiO 3 with similar final crystallite size. Finally, two different growth mechanisms were revealed, where the effect of surfactants present during hydrothermal synthesis is discussed as one of the key parameters.

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Section: Characterizationmentioning

confidence: 99%

Facile Low Temperature Hydrothermal Synthesis of BaTiO3 Nanoparticles Studied by In Situ X-ray Diffraction

et al. 2018

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“…Orthorhombic T-Nb 2 O 5 powder 27 was synthesized by precipitation from (NH 4 )NbO(C 2 O 4 ) 2 ·5H 2 O (Sigma-Aldrich, 99.99%) dissolved in water by adding aqueous ammonia solution (25 wt %, Emsure) before drying and then calcining at 600 °C for 12 h, as described by Mokkelbost et al 25 , 28 Highly concentrated suspensions were made by mixing T-Nb 2 O 5 powder with 9 or 12 M NaOH aqueous solutions, giving a Na/Nb ratio of 9.5 or 13.2. The suspensions were stored in PET bottles and injected with a plastic syringe into a custom-made in situ cell, making sure to fill the entire volume of the cell.…”

Section: Methodsmentioning

confidence: 99%

Understanding the Hydrothermal Formation of NaNbO₃: Its Full Reaction Scheme and Kinetics

et al. 2021

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Sodium niobate (NaNbO 3 ) attracts attention for its great potential in a variety of applications, for instance, due to its unique optical properties. Still, optimization of its synthetic procedures is hard due to the lack of understanding of the formation mechanism under hydrothermal conditions. Through in situ X-ray diffraction, hydrothermal synthesis of NaNbO 3 was observed in real time, enabling the investigation of the reaction kinetics and mechanisms with respect to temperature and NaOH concentration and the resulting effect on the product crystallite size and structure. Several intermediate phases were observed, and the relationship between them, depending on temperature, time, and NaOH concentration, was established. The reaction mechanism involved a gradual change of the local structure of the solid Nb 2 O 5 precursor upon suspending it in NaOH solutions. Heating gave a full transformation of the precursor to HNa 7 Nb 6 O 19 ·15H 2 O, which destabilized before new polyoxoniobates appeared, whose structure depended on the NaOH concentration. Following these polyoxoniobates, Na 2 Nb 2 O 6 ·H 2 O formed, which dehydrated at temperatures ≥285 °C, before converting to the final phase, NaNbO 3 . The total reaction rate increased with decreasing NaOH concentration and increasing temperature. Two distinctly different growth regimes for NaNbO 3 were observed, depending on the observed phase evolution, for temperatures below and above ≈285 °C. Below this temperature, the growth of NaNbO 3 was independent of the reaction temperature and the NaOH concentration, while for temperatures ≥285 °C, the temperature-dependent crystallite size showed the characteristics of a typical dissolution–precipitation mechanism.

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“…Such in situ and in operando studies have given valuable new insight into the synthesis of materials, e.g. under hydro-and solvo-thermal conditions (Millange et al, 2010;Jensen et al, 2012;Skjaervø et al, 2018), catalysts under operating conditions (Frenkel et al, 2012;Andersen et al, 2017) and materials under high pressure (Jiang et al, 2016;Briggs et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Experimental setup for high-temperature in situ studies of crystallization of thin films with atmosphere control

Blichfeld¹,

Bakken²,

Chernyshov³

et al. 2020

J Synchrotron Radiat

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Understanding the crystallization process for chemical solution deposition (CSD) processed thin films is key in designing the fabrication strategy for obtaining high-quality devices. Here, an in situ sample environment is presented for studying the crystallization of CSD processed thin films under typical processing parameters using near-grazing-incidence synchrotron X-ray diffraction. Typically, the pyrolysis is performed in a rapid thermal processing (RTP) unit, where high heating rates, high temperatures and atmosphere control are the main control parameters. The presented in situ setup can reach heating rates of 20°C s−1 and sample surface temperatures of 1000°C, comparable with commercial RTP units. Three examples for lead-free ferroelectric thin films are presented to show the potential of the new experimental set-up: high temperature, for crystallization of highly textured Sr0.4Ba0.6Nb2O6 on a SrTiO3 (001) substrate, high heating rate, revealing polycrystalline BaTiO3, and atmosphere control with 25% CO2, for crystallization of BaTiO3. The signal is sufficient to study a single deposited layer (≥10 nm for the crystallized film) which then defines the interface between the substrate and thin film for the following layers. A protocol for processing the data is developed to account for a thermal shift of the entire setup, including the sample, to allow extraction of maximum information from the refinement, e.g. texture. The simplicity of the sample environment allows for the future development of even more advanced measurements during thin-film processing under non-ambient conditions.

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

Cited by 20 publications

References 22 publications

Facile Low Temperature Hydrothermal Synthesis of BaTiO3 Nanoparticles Studied by In Situ X-ray Diffraction

Facile Low Temperature Hydrothermal Synthesis of BaTiO3 Nanoparticles Studied by In Situ X-ray Diffraction

Understanding the Hydrothermal Formation of NaNbO₃: Its Full Reaction Scheme and Kinetics

Experimental setup for high-temperature in situ studies of crystallization of thin films with atmosphere control

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

Cited by 20 publications

References 22 publications

Facile Low Temperature Hydrothermal Synthesis of BaTiO3 Nanoparticles Studied by In Situ X-ray Diffraction

Facile Low Temperature Hydrothermal Synthesis of BaTiO3 Nanoparticles Studied by In Situ X-ray Diffraction

Understanding the Hydrothermal Formation of NaNbO3: Its Full Reaction Scheme and Kinetics

Experimental setup for high-temperature in situ studies of crystallization of thin films with atmosphere control

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Product

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

Understanding the Hydrothermal Formation of NaNbO₃: Its Full Reaction Scheme and Kinetics