Cluster mediated conversion of amorphous Al(OH)3 to γ-AlOOH

Baccarella, Alicia; Garrard, Rhiannon; Beauvais, Michelle L.; Bednarksi, U.; Fischer, S.; Abeykoon, A. M. Milinda; Chapman, Karena W.; Phillips, Brian L.; Parise, John B.; Simonson, J. W.

doi:10.1016/j.jssc.2021.122340

Cited by 13 publications

(3 citation statements)

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“…The 27 Al NMR spectroscopy is widely used to clarify the local aluminum environment in various materials. In aluminate, the Al atom usually existed in four-fold coordination, five-fold coordination, and six-fold coordination. , As shown in Figure c, the [AlO 4 ], [AlO 5 ], and [AlO 6 ] are revealed to exist in phosphors corresponding to three kinds of 27 Al chemical shift of 77–82, 25–35, and 10–15 ppm, respectively. , The phosphors clearly show main resonances assigned to [AlO 4 ] (higher chemical shift) since the aluminum mainly exists as [AlO 4 ] in the two crystal structures of Ba 2 ScAlO 5 . The appearance of [AlO 5 ] and [AlO 6 ] may be due to the structural defects caused by the doping of Eu 3+ and the formation of small impurity phases, such as EuCaAl 3 O 7 and Ba 5 Sc 4 AlO 12.5 .…”

Section: Resultsmentioning

confidence: 94%

Synthesis of the Red-Emitting (Ba, Ca)₂ScAlO₅:Eu³⁺ Phosphors with Photoluminescence Properties

et al. 2022

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The light-emitting diodes (LED) are regarded as one of the most promising devices for inexpensive and widely used illumination; in particular, they are highly dependent on the development of red-emitting phosphors. Herein, we developed two types of red-emitting (Ba, Ca) 2 ScAlO 5 :Eu 3+ multiple excitations phosphors (λ ex = 255−465 nm) via freeze-drying followed by calcination. Powder X-ray diffraction and NMR results point out that they have hexagonal space group P6 3 /mmc (194), and the structural framework is composed of multi-coordinated Al 3+ −O 2− polyhedron and Sc 3+ −O 2− polyhedron. In addition, the valence state of europium (Eu 3+ ) is confirmed by X-ray photoelectron spectroscopy characterization. Investigation on the photoluminescence properties showed that the photoluminescence process of (Ba, Ca) 2 ScAlO 5 :Eu 3+ is attributable to the charge transfer band of Eu−O and abundant spectral terms of Eu 3+ . The α-(Ba, Ca) 2 ScAlO 5 :Eu 3+ and β-(Ba, Ca) 2 ScAlO 5 :Eu 3+ exhibited red emission under 465 and 395 nm excitation, respectively. The PL spectra and decay curves explain the intrinsic photoluminescence mechanism. The strongest emission peaks of the red-emitting α-(Ba, Ca) 2 ScAlO 5 :Eu 3+ and β-(Ba, Ca) 2 ScAlO 5 :Eu 3+ phosphors are at 615 and 619 nm, respectively, exhibiting a high fluorescence of 64 and 67% under the temperature of 423 K (150 °C). Further exploration of the red-emitting phosphors would provide a variety of choices for the design of red LEDs and white LEDs for the solid-state lighting system.

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Section: Resultsmentioning

confidence: 94%

Synthesis of the Red-Emitting (Ba, Ca)₂ScAlO₅:Eu³⁺ Phosphors with Photoluminescence Properties

et al. 2022

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“…AlOOH-80 showed a higher chemical shift field, which was attributed to the electronic shielding effect of the abundant OH defects on the Al nucleus. 37,44…”

Section: Resultsmentioning

confidence: 99%

Significantly enhanced catalytic performance of Pd nanocatalyst on AlOOH featuring abundant solid surface frustrated Lewis pair for improved hydrogen activation

Li,

Yin,

Liu

et al. 2024

RSC Adv.

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“…This is because NH 4 HCO 3 , the precipitant, provides CO 3 2− ions and creates an alkaline precipitation environment. In addition, there are diffraction peaks of Al(OH) 3 consistent with 24-0006, which are from AlOOH combined with H 2 O [ 13 ].…”

Section: Resultsmentioning

confidence: 99%

Synthesis of a Flaky CeO2 with Nanocrystals Used for Polishing

Zhang,

Gou

2024

Materials

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It is important to adapt the morphology of CeO2 to different applications. A novel flaky CeO2 with nanocrystals was successfully synthesized using the ordinal precipitation method and calcination. The size of the flaky CeO2 was about 10 μm, and the nanocrystals were about 100 nm. Under the action of the precipitant NH4HCO3, Ce3+ nucleated in large quantities. The nanosized crystals gathered into flakes driven by the surface energy. As the calcination temperature increased, the grains grew slowly by mass transfer due to the slow diffusion of reactants. By adding AlOOH to the starting material, the Al3+ doped into the CeO2 increased the content of Ce3+ in the CeO2, which improved the chemical activity of the CeO2. When the starting material’s Al:Ce ratio was 5:1, the Ce3+ increased to 31.11% in the CeO2, which provided good application potential in the polishing field. After polishing by the slurry of flaky CeO2 for 1 h, the SiC surface roughness reduced from 464 nm to 11 nm.

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Cluster mediated conversion of amorphous Al(OH)3 to γ-AlOOH

Cited by 13 publications

References 58 publications

Synthesis of the Red-Emitting (Ba, Ca)₂ScAlO₅:Eu³⁺ Phosphors with Photoluminescence Properties

Synthesis of the Red-Emitting (Ba, Ca)₂ScAlO₅:Eu³⁺ Phosphors with Photoluminescence Properties

Significantly enhanced catalytic performance of Pd nanocatalyst on AlOOH featuring abundant solid surface frustrated Lewis pair for improved hydrogen activation

Synthesis of a Flaky CeO2 with Nanocrystals Used for Polishing

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Cluster mediated conversion of amorphous Al(OH)3 to γ-AlOOH

Cited by 13 publications

References 58 publications

Synthesis of the Red-Emitting (Ba, Ca)2ScAlO5:Eu3+ Phosphors with Photoluminescence Properties

Synthesis of the Red-Emitting (Ba, Ca)2ScAlO5:Eu3+ Phosphors with Photoluminescence Properties

Significantly enhanced catalytic performance of Pd nanocatalyst on AlOOH featuring abundant solid surface frustrated Lewis pair for improved hydrogen activation

Synthesis of a Flaky CeO2 with Nanocrystals Used for Polishing

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Product

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Synthesis of the Red-Emitting (Ba, Ca)₂ScAlO₅:Eu³⁺ Phosphors with Photoluminescence Properties

Synthesis of the Red-Emitting (Ba, Ca)₂ScAlO₅:Eu³⁺ Phosphors with Photoluminescence Properties