Journal of Physical Chemistry C
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2013
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IF 4.814
Yongfeng Liu,Chao Li,Bo Li,Mingxia Gao,Hongge Pan
The hydrogen storage properties and mechanisms of the Mg(NH2)2–2LiH system with potassium halides (KF, KCl, KBr, and KI) were investigated and discussed. The results show that the KF-added sample exhibits superior hydrogen storage properties as ∼5.0 wt % of hydrogen can be reversibly stored in the 0.08KF-added sample via a two-stage reaction with an onset dehydrogenation temperature of 80 °C. However, hydrogen storage behaviors of the samples with KCl, KBr, and KI remain almost unchanged. The fact that KF can readily react with LiH to convert to KH and LiF due to the favorable thermodynamics during ball milling should be the primary reason for its significant effects, as the presence of KH provides a synergetic thermodynamic and kinetic destabilization in the hydrogen storage reaction of the Mg(NH2)2–2LiH system by declining the activation energy of the first-step dehydrogenation as a catalyst and reducing the desorption enthalpy change of the second step as a reactant. The understanding on the role played by KF sheds light on how to further decrease the operating temperature and enhance the hydrogen storage kinetics of the metal–N–H system.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-12
·
IF 14.7
Zhang Chang,Yu Jiameng,Cui Yuanyuan,Lv Yinjie,Zhang Yue,Gao Tianyi,He Yuxi,Chen Xin,Li Tao,Lin Tianquan,Mi Qixi,Yu Yi,Liu Wei
Garnet oxide is one of the most promising solid electrolytes for solid-state lithium metal batteries. However, the traditional interface modification layers cannot completely block electron migrating from the current collector to the interior of the solid-state electrolyte, which promotes the penetration of lithium dendrites. In this work, a highly electron-blocking interlayer composed of potassium fluoride (KF) is deposited on garnet oxide Li 6.4 La 3 Zr 1.4 Ta 0.6 O 12 (LLZTO). After reacting with melted lithium metal, KF in-situ transforms to KF/LiF interlayer, which can block the electron leakage and inhibit lithium dendrite growth. The Li symmetric cells using the interlayer show a long cycle life of ~3000 hours at 0.2 mA cm −2 and over 350 hours at 0.5 mA cm −2 respectively. Moreover, an ionic liquid of LiTFSI in C 4 mim-TFSI is screened to wet the LLZTO|LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM) positive electrode interfaces. The Li|KF-LLZTO | NCM cells present a specific capacity of 109.3 mAh g −1 , long lifespan of 3500 cycles and capacity retention of 72.5% at 25 °C and 2 C (380 mA g −1 ) with an average coulombic efficiency of 99.99%. This work provides a simple and integrated strategy on high-performance quasi-solid-state lithium metal batteries.
研究领域:
材料科学
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电化学
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产品关联
DOI
PubMed
高影响因子
SYNTHESIS-STUTTGART
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2024
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IF 2.2
Taijie Guo,Wei Wang,Long Xu,Jiajia Dong
Here we report the utilization of NH-sulfamoyl fluorides (RNHSO2F) as reliable SuFEx synthons for the construction of various sulfamate esters. By using potassium fluoride as base, we are able to convert RNHSO2F to azasulfene intermediates under mild conditions and guarantee their further efficent ligation with phenols and alcohols.
研究领域:
有机化学
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合成化学
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DOI
高影响因子
ELECTROCHEMISTRY
·
2019
·Vol. 87
·期 3
·142-147
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IF 1.293
Handong JIAO,Junxiang WANG,Donghua TIAN,Shuqiang JIAO
The electrochemical behaviour of Ti4+ (K2TiF6) at liquid tin and bismuth electrodes has been investigated by cyclic voltammetry, square wave voltammetry and chronoamperometry in the LiF–NaF–KF eutectic melt. Result shows that, on the liquid metal electrodes, the reduction reaction of the solvent occurs at more positive potential than that on the inert molybdenum electrode. There are two reduction steps including Ti4+ + e = Ti3+ and Ti3+ + 3e = Ti (Ti–Sn alloys) on the liquid tin electrode within the electrochemical window of the melt. However, only one redox process corresponding to the redox of the Ti4+/Ti3+ couple is observed at liquid bismuth electrode.
研究领域:
电化学
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材料科学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2017
·Vol. 7
·期 3
·725-733
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IF 5.773
Ning Liu,Zhimin Wu,Meng Li,Shanshan Li,Yongfei Li,Rongdong Yu,Langsheng Pan,Yuejin Liu
Bimetallic Al–La oxides were conjointly precoated on SBA-15 prior to the introduction of potassium fluoride to achieve solid superbases at low temperature by a modified wetness impregnation method. This breaks the tradition of decomposition of KNO3 at high temperature and gives rise to a new approach to generating superbasic sites on SBA-15. The physico-chemical characteristics of the prepared KF/Al–La@SBA-15 materials were investigated using FT-IR, XRD, TG-DTG, N2 adsorption–desorption, TEM, SEM-EDS, acid–base titration, Hammett indicators and CO2-TPD measurements. The results demonstrated that the addition of Al species promoted the dispersion behavior of La species inside the channels, and the bimetallic species could synergistically protect the mesoporous structures of SBA-15 against KF corrosion. With increasing Al content, KF/Al–La@SBA-15 exhibited a long-range ordering of the pores with relatively narrow pore size distribution as well as high specific surface area. The research results showed that the KF/Al–La@SBA-15 (0.4) catalyst possessed a total basicity up to 0.79 mmol g−1 and superbasicity with a strength of 26.5. The catalytic activity of the prepared materials was evaluated in the ring-opening reaction of propylene oxide with methanol. Compared with the SBA-15 supported monometallic oxide (Al or La) catalysts, KF/Al–La@SBA-15 (0.4) exhibited the highest catalytic activity for the ring-opening reaction of propylene oxide with methanol. This is associated with the synergistic effects between Al and La species and the high dispersion of active components on the SBA-15 support.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
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2024
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IF 5.5
Yueyue He,Huaigang Cheng,Zihe Pan,Xiangping Zhang
Heterogeneous catalysts can avoid the problem of difficult separation and recovery of homogeneous catalysts in transesterification reactions, but there is a lack of basis for process optimization because the quantitative influence mechanism of supports is not clear. In this work, we firstly attempt to make a comprehensive comparation on the effect of potassium fluoride (KF) catalysts on various supports (carbonates and oxides of cerium, magnesium and calcium) on the transesterification reaction, especially on the kinetics. According to the results, oxide-supported catalysts are significantly more active than carbonate-supported catalysts because they have more active sites. When oxides were used as supports, KF/MgO exhibited good activity because of its stronger basicity and higher number of active sites on the surface. Under the same process conditions, the stability time of KF/CeO 2 , KF/CaO and KF/MgO catalysed transesterification reaction was 240 min, 90 min and 30 min, respectively. KF/MgO achieved a conversion of 68.0 %. The activation energies of the KF/CeO 2 , KF/CaO and KF/MgO catalysed transesterification reaction were 22.22 kJ/mol, 15.93 kJ/mol and 15.80 kJ/mol, respectively. The surface alkalinity of KF/MgO increased the frequency of molecular collisions of the reactants and exhibited a faster reaction rate.
研究领域:
催化化学
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材料科学
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反应工程学
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DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 1
·239-246
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IF 2.305
Peng Jianping,Wei Zheng,Di Yuezhong,Wang Yaowu,Sun Ting
NaF-KF-LiF-AlF 3 -based low-temperature electrolytes have attracted great interest because of their potential to optimize and improve current industrial aluminum production methods. In the present study, the saturated alumina solubility in quaternary NaF-KF-LiF-AlF 3 -based melts (total cryolite molar ratio \( {\text{CR}} = \left( {n_{\text{NaF}} + n_{\text{KF}} + n_{\text{LiF}} } \right)/n_{{{\text{AlF}}_{3} }} \) of 1.3) with both KF and LiF content of 0 mol.% to 20 mol.% were evaluated by measuring the weight loss of a rotating corundum disk over the temperature range of 800–920°C. The effects of the KF content, LiF content, and temperature on alumina solubility are discussed in detail. The results fit well with the following empirical equation within the temperature of 830–890°C: ω (Al 2 O 3 ) sat = A × ( t /1000) B , where A = 0.3101[KF] − 0.1254[LiF] − 0.0057[KF] 2 + 0.0028[LiF] 2 + 4.486, B = 0.3839[KF] + 0.0368[LiF] − 0.0140[KF] 2 + 0.0057[LiF] 2 + 4.913, and t is the temperature in Celsius. Alumina solubility diagrams at various temperatures are illustrated based on the empirical regression equation obtained. Finally, some problems and challenges preventing the application of these low-temperature melts in industry are discussed.
研究领域:
冶金学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
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