Metastable Sr_0.5TaO₃ Perovskite Oxides Prepared by Nanosheet Processing

Abstract

Metastable Sr0.5TaO3 with a perovskite structure was prepared by using layer‐structured H2Sr1.5Ta3O10 by two different processes: direct dehydration and nanosheet processing, and the photocatalytic activities of the obtained structures were investigated for the evolution of H2 and O2 from distilled water under UV light irradiation. The average gas evolution rates were 66 μmol h–1 (H2) and 16 μmol h–1 (O2) for Sr0.5TaO3 prepared by direct dehydration, whereas those obtained by nanosheet processing were 126 μmol h–1 (H2) and 33 μmol h–1 (O2). It was shown that nanosheet processing is effective for obtaining metastable Sr0.5TaO3 with high photocatalytic activities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Promising Oxonitridosilicate Phosphor Host Sr3Si2O4N2: Synthesis, Structure, and Luminescence Properties Activated by Eu2+ and Ce3+/Li+ for pc-LEDs

“…47,48 The values of (αhυ) 1/2 are plotted as a function of the incident photon energy (hυ) as illustrated in the inset of Figure 8. From the linear extrapolation of (αhυ) 1/2 = 0, the E g value was estimated to be about 2.71 eV, which is consistent with the value of 2.84 eV obtained from DFT calculation.…”

Observation of octahedral tilted in Sr0.5TaO3 prepared by nanosheet processing: An EXAFS study

“…These planar defects are found to enhance the large Ta-O-Ta bond angle distortion of TaO 6 octahedra (smaller ␣) in RE-Sr 0.5 TaO 3 . It is tentatively proposed that the planar defects and/or the large Ta-O-Ta bond angle distortion of TaO 6 octahedra (smaller ␣) are the origin of the enhanced photocatalytic activity in RE-Sr 0.5 TaO 3 [32].…”

“…While Sr 0.5 TaO 3 is derived by direct dehydration from H 2 Sr 1.5 Ta 3 O 10 , RE-Sr 0.5 TaO 3 is obtained by nanosheet processing from RE-H 2 Sr 1.5 Ta 3 O 10 with a high concentration of stacking fault along the c-axis [32]. It is reasonable to consider that the stacking faults in RE-H 2 Sr 1.5 Ta 3 O 10 are partially inherited by RE-Sr 0.5 TaO 3 and that RE-Sr 0.5 TaO 3 has a planar defect resulting from the stacking faults in the parent RE-H 2 Sr 1.5 Ta 3 O 10 .…”

“…The mixture reacted at room temperature for 3 days, which produced the nanosheets of (Sr1.5Ta3O10) 2− suspended in the solution [32]. The resulting colloidal suspension of (Sr1.5Ta3O10) 2− nanosheets was subjected to centrifugal separation and the supernatant solution was taken for further use.…”

“…Inaba et al [32] have recently reported the photocatalytic properties of metastable Sr 0.5 TaO 3 with perovskite structure, which was obtained by two methods: direct dehydration and nanosheet processing. Sr 0.5 TaO 3 powder obtained by nanosheet processing exhibited a superior photocatalytic activity than that obtained by direct dehydration, but the detailed crystal structures such as Ta-O-Ta bond angle, Ta-O bond length and so on have not been elucidated by X-ray diffraction (XRD) analysis due to profile broadening.…”