Preparation and Characterization of Sodium Tantalate Thin Films by Hydrothermal−Electrochemical Synthesis

Lee, Yungi; Watanabe, Tomoaki; Takata, Tsuyoshi; Kondo, Junko N.; Hara, Michikazu; Yoshimura, Masahiro; Domen, Kazunari

doi:10.1021/cm0500859

Cited by 54 publications

(29 citation statements)

References 20 publications

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“…Thus far, polycrystalline NaTaO 3 films have been prepared by hydrothermal reactions [12][13][14][15], synthesis under NaNO 3 flux [16,17], and magnetron sputtering [18]. In this study, hydrothermal and solvothermal reactions were employed to produce epitaxial films on SrTiO 3 substrates.…”

Section: Previously Reported Natao 3 Filmsmentioning

confidence: 99%

Heteroepitaxial barium-doped NaTaO 3 films on SrTiO 3 (001) substrate

Fujiwara

Park

et al. 2018

Thin Solid Films

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Perovskite-structured NaTaO 3 films were epitaxially deposited on centimeter-sized SrTiO 3 (001) wafers by hydrothermal and solvothermal reactions to examine the surface science for an efficient photocatalytic water-splitting reaction. The addition of Ba cations in the starting solutions afforded Badoped NaTaO 3 films. X-ray fluorescence holography was employed to investigate and confirm the heteroepitaxial relationship between the Ba-doped film and substrate.  Hydrothermal and solvothermal preparation of NaTaO 3 heteroepitaxial films on SrTiO 3 (001).  Doping with Ba 2+ cations up to 4 mol% relative to Ta.  Feasibility of X-ray fluorescence holography for NaTaO 3 film characterization.

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Section: Previously Reported Natao 3 Filmsmentioning

confidence: 99%

Heteroepitaxial barium-doped NaTaO 3 films on SrTiO 3 (001) substrate

Fujiwara

Park

et al. 2018

Thin Solid Films

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“…In parallel to that, significant attention has been paid to further factors such as crystallinity, particle size, morphology, and presence of structural defects (e.g., oxygen vacancies), equally crucial for developing efficient photocatalysts. Such properties are synthesis route-dependent and have been effectively tuned by a wide range of wet chemical synthesis methods including hydrothermal [ 15 , 16 ], sol-gel [ 17 ], and coating Ta substrate with molten NaNO 3 , followed by annealing treatment [ 18 , 19 ]. However, few works report the fabrication of NaTaO 3 thin films from vapor phase [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Widely Tuneable Composition and Crystallinity of Graded Na1+xTaO3±δ Thin Films Fabricated by Chemical Beam Vapor Deposition

et al. 2022

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Combinatorial approach has been widely recognized as a powerful strategy to develop new-higher performance materials and shed the light on the stoichiometry-dependent properties of known systems. Herein, we take advantage of the unique features of chemical beam vapor deposition to fabricate compositionally graded Na1+xTaO3±δ thin films with −0.6 < x < 0.5. Such a varied composition was enabled by the ability of the employed technique to deliver and combine an extensive range of precursors flows over the same deposition area. The film growth occurred in a complex process, where precursor absolute flows, flow ratios, and substrate temperature played a role. The deviation of the measured Na/Ta ratios from those predicted by flow simulations suggests that a chemical-reaction limited regime underlies the growth mechanism and highlights the importance of the Ta precursor in assisting the decomposition of the Na one. The crystallinity was observed to be strongly dependent on its stoichiometry. High under-stoichiometries (e.g., Na0.5TaO3−δ) compared to NaTaO3 were detrimental for the formation of a perovskite framework, owing to the excessive amount of sodium vacancies and oxygen vacancies. Conversely, a well-crystallized orthorhombic perovskite structure peculiar of NaTaO3 was observed from mildly under-stoichiometric (e.g., Na0.9TaO3−δ) to highly over-stoichiometric (e.g., Na1.5TaO3+δ) compositions.

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“…However, usual catalysis studies have been performed with NaTaO 3 powder samples, and it prevented the fine bulk and surface characterization. In order to approach and reveal the basic mechanism of bulk and surface reactions of the NaTaO 3 material, film and substrate preparations by the hydrothermal reaction [8−11], the sol-gel synthesis [12,13], the flux synthesis [14,15], and any other deposition methods [16−19] have been studied. However, prepared films by these methods were consisted to be polycrystalline NaTaO 3 crystals with complex orientation so that it was not suitable for detailed investigations of the bulk and surfaces of NaTaO 3 .…”

Section: Introductionmentioning

confidence: 99%

Preparation of the NaTaO<sub>3</sub> Crystal from the KTaO<sub>3</sub> Substrate via Topotactic Alkaline Cation Substitution as Confirmed by Transmission Electron Microscopy

Kitta

Ōnishi

2020

e-J. Surf. Sci. Nanotechnol.

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Orthorhombic-type sodium tantalite (NaTaO 3 ) is one of the most promising photocatalyst for hydrogen generation via water splitting reaction with ultraviolet-irradiation. In this research, we prepared NaTaO 3 crystal from KTaO 3 substrate via solid-state K + −Na + alkaline cation substitution. In the transmission electron microscopy (TEM) observation revealed the perovskite-type KTaO 3 crystal phase is transformed into the orthorhombic crystal phase via simple heating of KTaO 3 substrate with Na 2 O 2 . Atomic scale scanning TEM imaging with energy dispersive X-ray spectroscopy (EDS) are supported that this phase transformation clearly based on the topotactic alkaline cation substitution with K + and Na + at a common Ta-O basic lattice structure.

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Preparation and Characterization of Sodium Tantalate Thin Films by Hydrothermal−Electrochemical Synthesis

Cited by 54 publications

References 20 publications

Heteroepitaxial barium-doped NaTaO 3 films on SrTiO 3 (001) substrate

Heteroepitaxial barium-doped NaTaO 3 films on SrTiO 3 (001) substrate

Widely Tuneable Composition and Crystallinity of Graded Na1+xTaO3±δ Thin Films Fabricated by Chemical Beam Vapor Deposition

Preparation of the NaTaO<sub>3</sub> Crystal from the KTaO<sub>3</sub> Substrate via Topotactic Alkaline Cation Substitution as Confirmed by Transmission Electron Microscopy

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