JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Tianping Huang,Jianxin Zou,Ning Zhao,Xiaoqin Zeng,Wenjiang Ding
A new reversible hydrogen storage system, 3NaBH 4 -0.5ScF 3 -0.5YF 3 , was synthesized by using the ball-milling method. It is shown that no reaction occurs during the ball-milling process. The hydrogen desorption process of the ball-milled composite can be divided into three consecutive steps: (i) An initial stage from room temperature to 320 °C with about 0.42 wt% of hydrogen released, that can be ascribed to the substitution of H − by F − in NaBH 4 ; (ii) The second stage starts from 320 °C to 450 °C, releasing about 1.06 wt% of hydrogen; (iii) The final stage ranges from 450 °C to 480 °C, with 2.58 wt% of hydrogen released. The total yield of hydrogen reaches 4.06 wt% at 480 °C. The completely dehydrogenated products of the 3NaBH 4 -0.5ScF 3 -0.5YF 3 composite can absorb 2.15 wt% of hydrogen at 380 °C in 6.5 h, which shows greatly enhanced reversibility when compared with sole ScF 3 addition. It should be noted that one of the destabilizers ScF 3 was also regenerated besides NaBH 4 in the rehydrogenated products. Based on the XRD and FTIR analyses, the synergistic effects of 3d transition metal fluoride ScF 3 and rare earth metal fluoride YF 3 on the hydrogen desorption and absorption performance of NaBH 4 were discussed.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 17
·9211-9217
·
IF 2.936
Ning Zhao,Jianxin Zou,Xiaoqin Zeng,Wenjiang Ding
A new hydrogen storage composite containing NaBH4 and a 3d transition metal fluoride, 3NaBH4/ScF3, was synthesized via ball milling. The composite shows no reaction during milling and its dehydriding process can be divided into three steps upon heating: (i) partial substitution of H− by F− in NaBH4 to form NaBHxF4−x at the early stage, releasing about 0.19 wt% of hydrogen; (ii) formations of Na3ScF6, NaBF4 and ScB2 through the reaction between NaBH4 and ScF3, with 2.52 wt% of hydrogen release and a dehydriding activation energy of 162.67 kJ mol−1 H2; (iii) further reaction of residual NaBH4 and Na3ScF6 to form NaF, B and ScB2, with a dehydriding activation energy of 169.37 kJ mol−1 H2. The total hydrogen release of the composite reaches 5.54 wt% at 530 °C. The complete dehydrided composite cannot be rehydrogenated while the products after the second dehydriding step can be hydrogenated with an absorption activation energy of 44.58 kJ mol−1 H2. These results demonstrate that by adding 3d transition metal fluorides into NaBH4, a partial reversibility in NaBH4 can be achieved.
研究领域:
材料科学
·
氢存储
·
能源材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2018
·
IF 2.179
Rui Zhu,Yushun Zeng,Shanchuan Liang,Yu Zhang,Yunhui Qi,Yunfei Liu,Yinong Lyu
A facile microwave-assisted hydrothermal method has been employed to synthesize a series of ScF 3 : x Eu 3+ , y Bi 3+ ( x = 0 −0.20, y = 0–0.05) crystals to improve the fluorescence performance by optimizing the concentrations of Eu 3+ ions and Bi 3+ ions. The as-obtained products then were characterized by thermal field emission scanning electron microscope (FE-SEM), X-ray powder diffractometer (XRD), high resolution transmission electron microscope (HRTEM), and photoluminescence (PL) spectrometer, systematically. The results manifest that the reaction temperature and reaction time play an significantly important role on the morphologies and sizes of the as-prepared products. Furthermore, the optical properties of ScF 3 : x Eu 3+ , y Bi 3+ samples was investigated in detail. The emission spectra of ScF 3 : x Eu 3+ recorded upon the excitation wavelength of 394 nm showed a strong emission peak located at 592 nm, which is corresponding to the magnetic dipole of the 5 D 0 – 7 F 1 transition of Eu 3+ ions. Additionally, it was found that the luminescence of the samples has been deeply enhanced after the addition of an appropriate amount of Bi 3+ . The opportune concentration of Eu 3+ and Bi 3+ are x = 0.10 and y = 0.02, respectively.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2020
·Vol. 96
·期 3
·753-762
·
IF 2.008
Zhu Rui,Bi Zun,Jia Ke,Liu Yunfei,Lyu Yinong
A series of single-component ScF 3 :Dy 3+ , Eu 3+ , Ce 3+ phosphors prepared by means of microwave hydrothermal method were explored for light-emitting diodes. The as-prepared samples were characterized via X-ray diffraction (XRD), scanning electron microscope (SEM), and photoluminescence (PL) spectroscopy. In order to rationalize the experimental results, first-principle calculations based on density functional theory had been carried out to discover electronic structures. PL performance of the RE 3+ -doped phosphors exhibited well-defined bands in the visible region. By adjusting the ratios of Ce/Dy/Eu, the color of the as-prepared phosphors can vary from blue (0.24, 0.23) to red (0.51, 0.30) across the white (0.34, 0.26) region according to the chromaticity coordinates. The results suggested that the Dy/Eu/Ce-doped ScF 3 might act as down-convert phosphors for near ultraviolet light-emitting diodes, especially for white LEDs. What is more, it can also promote a deep comperhension of the relationship between structure and properties in ScF 3 -based phosphors.
ScF 3 :RE 3+ phosphors with alterable bandgaps can emit light from blue to orange–red across white under the excitation of near ultraviolet light. Introduction of rare earth ions induced the variation of energy band structures in ScF 3 -based phosphors because of the existence of f , p , and d orbits in RE 3+ , therein f and p orbits of RE 3+ made the band structure downwards, the p hybridizing with Sc-3 d promoted the band toward high-energy region.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 17
·5984
·
IF 3.4
Zhi Li,Chengwei Zhan,Huan Yu,Xitao Wang,Shouqiu Tang,Jixue Zhou,Jianhua Wu
Research on rare-earth fluorides is of urgent and critical importance for the preparation and emerging applications of high-purity alloys. The fluorination of Sc2O3by NH4HF2to fabricate ScF3is investigated. The effects of the fluorination temperature, time and mass ratio of reactant on the fluorination rate and fluoride are discussed in this work. The fluorination reaction was first confirmed using thermodynamic calculation. The thermal and mass stability of the fluorination process were analyzed by thermogravimetric and differential scanning calorimetric (TG-DSC). The as-obtained products at different fluorination temperatures were characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results indicated that the fluorination began at room temperature (RT) with the formation of (NH4)3ScF6. With the increase of temperature, the reaction proceeded sequentially through the formation of NH4ScF4, (NH4)2Sc3F11, and finally ScF3. The fluorination rate increased with the increase of fluorination temperature and holding time. ScF3with a purity of 99.997 wt.% could be obtained by fluorination at 400 °C for 2 h.Keywords:Sc2O3;(NH4)3ScF6;NH4ScF4;(NH4)2Sc3F11;ScF3
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materiomics
·
2025
·
IF 9.6
Jin Cheng,Hongye Wang,Xinwei Xu,Naichao Chen,Zhan Zeng,Xiaoyu Li,Biao Guo,Binfeng Zhao,Hong Wang
To meet the demands of miniaturization and integration in modern electronic packaging, developing materials with low coefficient of thermal expansion (CTE) is essential to reduce thermal stress and enhance device reliability. In this study, the dense negative thermal expansion ceramic ScF 3 was prepared with a CTE of –8.86×10 –6 /°C. The ScF 3 ceramic was cold sintered at 150 °C, exhibiting a low permittivity of 5.3 and a high quality factor ( Q × f ) of 14,700 GHz. By incorporating ScF 3 to the hexagonal boron nitride (BN) ceramic, the CTE of ScF 3 -BN composite ceramic was adjusted to 3.36×10 –6 /°C, establishing compatibility with silicon-based chips. And finite element simulations verified that ScF 3 -BN composite significantly reduces thermal stress compared to Li 2 MoO 4 or Al 2 O 3 ceramics. Furthermore, this work demonstrates the potential of cold-sintered ScF 3 to regulate thermal expansion in packaging substrates, paving the way for improved performance in next-generation electronic devices.
研究领域:
材料科学
·
电子工程
·
陶瓷学
·
热管理
·
微电子封装
·
功能材料
·
固态物理
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2025
·Vol. 13
·期 27
·e01552
·
IF 7.2
Yongjie Wang,Yingju Yan,Dongshuo Li,Qingzhou Bu,Guotao Xiang,Li Li,Sha Jiang,Xianju Zhou,Qilong Gao,Yaroslav Zhydachevskyy,Mikhail G. Brik,Andrzej Suchocki
Broadband near-infrared (NIR) phosphors with superior thermal stability are critical enablers of high-power NIR pc-LEDs, emerging as essential light sources for NIR spectroscopy applications. In this work, an unprecedented high-temperature negative thermal quenching (NTQ) phenomenon persisting up to 500 K is reported in Cr 3+ -activated ScF 3 phosphors, which emit broadband NIR emission in the 700–1200 nm (λ em = 850 nm, FWHM = 132 nm). The theoretical calculations employing the Exchange-Charge Model (EMC) for crystal field parameters of Cr 3+ ions in [ScF 6 ] octahedral sites remain in perfect agreement with the experimental results. Critically, Yb 3+ -codoping enables efficient Cr 3+ → Yb 3+ energy transfer, achieving substantial spectral broadening (FWHM = 254 nm) and significantly enhanced thermal stability. The temperature-dependent X-ray diffraction (XRD) and theoretical calculations reveal that anisotropic F-atom vibrations drive negative thermal expansion (NTE) in cubic ScF 3 , distorting [ScF 6 ] octahedra. It is demonstrated that synergistic electron-phonon coupling and NTE-driven structural dynamics underpin the superior thermal stability of NIR emission. These findings establish a design paradigm for new broadband NIR phosphors with outstanding thermal stability for next-generation high-power NIR pc-LED applications.
研究领域:
材料科学
·
光子学
·
固态化学
·
光学材料
·
发光
·
热性能
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2016
·Vol. 18
·期 31
·5940-5951
·
IF 3.849
Jingjing Cao,Li Yuan,Shanshan Hu,Jianfeng Tang,Xianju Zhou,Jun Yang
Monodisperse ScF3 and NaScF4 nano-/micro-crystals were prepared by a simple solvothermal method. There were many important factors including the molar ratio of Na/F/(Sc + Ln) and Ln3+ doping to control the synthesis of the products. A phase transformation from monoclinic ScF3 to hexagonal NaScF4 was observed with different molar ratios of Na/F/Sc. Herein, the products doped with 1% Ln3+ (La–Lu, except Pm) demonstrated abundant phases, morphologies and sizes. Moreover, the products with different Lu3+ doping concentrations from 1% to 60% were prepared. The results revealed that different kinds of 1% Ln3+ (La–Lu, except Pm) and diverse concentrations of Lu3+ can modify the phase, morphology and size of the prepared products. A possible formation mechanism for the products with diverse morphologies is proposed. In addition, Ln3+-doped ScF3 or NaScF4 nano-/micro-crystals presented characteristic up/down-conversion fluorescence spectra.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Liuhan Yi,Ruoyu Fu,Feng Zhang,Zheng Wei,Man Zhang
The anomalous luminescence thermal quenching performance caused by negative thermal expansion has attracted much attention due to the potential application in optical fields . However, the downshifting emissions with abnormal thermal quenching achieved by isotropic negative thermal expansion for optical temperature sensing applications are still lacking. Herein, a large enhancement of red emission and a high temperature sensing performance are realized by isotropic negative thermal expansion in ScF 3 :Tb 3+ /Eu 3+ phosphors ceramics. Specially, a selectively thermal enhanced red emission of Eu 3+ from 5 D 0 → 7 F 2 with hypersensitive transition characteristics could be obtained due to the thermal stimulated lattice distortion . Attributing to the shortening of cation spacing, the energy transfer efficiency between Tb 3+ and Eu 3+ is largely enhanced with the increasing of the temperature from 303 to 473 K. The enhanced energy transfer leads to that the emission of Tb 3+ firstly increases and then slightly decreases, whereas the emission from Eu 3+ has been largely improved. Finally, an optical temperature sensing strategy based on the fluorescence intensity ratio of the sensitizer Tb 3+ (signal ions) and the activator Eu 3+ (referring ions) is designed, attributing to the distinguishable luminescence response to the temperature. The obtained maximum relative sensitivity is 1.04 % K −1 (@303 K). Besides, the sensing strategy based on lifetime mode also suggests a maximum relative sensitivity of 1.00 % K −1 at 343 K. It provides a feasible strategy to obtain an optical temperature sensing material with high emission efficiency at a high temperature, which sheds light on the design of luminescence materials keeping high luminescence stability in a wide temperature range in the fields of optical temperature sensing.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2024
·Vol. 14
·期 11
·797
·
IF 3.8
Hanyang Zhang,Wen Liu,Jiale Hu,Qian Zhang,Zeguo Fang,Dong Li
An efficient method involving copper-catalyzed trifluoromethylthiolation and radical cyclization ofN-phenylpent-4-enamides using readily available and stable AgSCF3as the trifluoromethylthiolating reagent is described. The method enables the synthesis of a series of potential medicinally valuable trifluoromethylthio-substitutedγ-lactams and relative 2-oxazolidinone derivatives with broad functional group compatibility. Mechanistic investigations indicated that this reaction involved amidyl radical-initiated cascade5-exo-trigcyclization followed by trifluoromethylthiolation, resulting in the formation of new C-N and C-S bonds.
研究领域:
有机化学
·
药物化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）