RARE METALS
·
2025
·
IF 11
You Lv,Qiang Yang,Jixing Zhu,Dongyue Zhao,Junyuan Fan,Valery Konstantinovich Sheleg,Xin Qiu
en Mg−Ni−Y alloy is considered to be one of the most promising hydrogen storage materials, but its high dehydrogenation energy barrier hinders its practical application. A dual-stage heat treatment (490°C × 4 h + 550°C × 4 h) is applied to optimize the microstructure and hydrogen storage performance of a vacuum-melted Mg 94 Ni 3 Y 3 alloy. This process induces a two-level phase transformation of the long-period stacking ordered (LPSO) structure (18R + 14H→14H→18R), facilitating Ni/Y atom pre-distribution via stacking fault recombination at 490°C and promoting a eutectic-like reaction at 550°C. As a result, a large-scale eutectic-like structure composed of finely dispersed and uniformly interwoven Mg 2 Ni and LPSO phases is formed, characterized by a high density of phase boundaries. The optimization of the microstructure directly leads to the enhancement of hydrogen storage performance, as evidenced by a reduction in dehydrogenation activation energy from 139.7 to 113.5 kJ mol −1 and a decrease in enthalpy change from 85.8 to 71.7 kJ mol −1 . This work demonstrates a convenient microstructure regulation strategy, which is expected to advance Mg−Ni−Y alloys toward industrial applications. 摘要 zh Mg−Ni−Y 合金因其优异的储氢潜力而备受关注,但较高的脱氢能垒仍制约其工程化应用。针对真空熔炼的Mg 94 Ni 3 Y 3 合金,本研究采用双阶段热处理工艺(490°C×4 h+550°C×4 h)调控其显微组织与储氢性能。结果表明,该工艺诱导长周期堆垛有序(LPSO)结构经历两级相变过程(18R+14H→14H→18R):在490°C通过层错重组实现Ni/Y原子的预分布,在550°C进一步促进类共晶反应的发生。由此形成的大尺度类共晶组织由细小弥散且均匀交织的Mg 2 Ni相与 LPSO 相构成,具有高密度相界特征。显微组织的显著优化有效降低了脱氢活化能(由139.7降至113.5 kJ mol −1 )和焓变(由85.8降至71.7 kJ mol −1 ),从而提升了储氢动力学性能。本工作提出了一种简便高效的组织调控策略,为Mg−Ni−Y合金的工程化应用提供了新思路。
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DOI
高影响因子
ANTI-CORROSION METHODS AND MATERIALS
·
2023
·Vol. 70
·期 3
·129-138
·
IF 1.2
Jiao Li,Tianshu Li,Jodie A. Yuwono,Guozhe Meng,Zhiyuan Feng
Purpose This study aims to develop a sol-gel-based coating to provide a long-lasting corrosion protection on AZ31 Mg alloy. Silane-based sol-gel coatings have been successfully applied to Mg alloys for corrosion protection. However, the micro or nano defects formed during condensation and solidification will cause the coating failure during a long-lasting immersion in a saline solution. More durable corrosion-protective sol-gel coatings are needed. Design/methodology/approach A sol-gel-based coating was modified on AZ31 Mg alloy by levodopa (DOPA). The long-lasting corrosion protection mechanism was studied by multiple electrochemical testing methods and surface characterization techniques. Findings Long-term testing by electrochemical impedance spectroscopy in aqueous 0.1 M NaCl indicated that the modified DOPA@sol-gel coating exhibited significant corrosion protection performance (>14 days). In comparison, the DOPA-free sol-gel coating failed only after three days of testing. The improved corrosion protection is attributed to the self-polymerized DOPA filling to the micro or nano defects in the glassy cross-linked networks of the sol-gel coating, which greatly improves the compactness of the coating. Originality/value The method of this study is simple and easy to process, the raw materials are green and the protective effect is excellent, which is of significance for the study of magnesium alloy corrosion protection.
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DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Weiping Liao,Haoyi Lin,Mengdie Yin,Jiaxing Zhang,Zhiguo Zhu,Hongying Lü
The confinement of metal-based matrix such as clusters, particles and even isolated single atoms in zeolite framework was intensively reported, while it was highly untoward to realize this goal for non-metallic ions due to the mutually-exclusive electrostatic interaction between the zeolite framework with negative charges and non-metallic anions. Herein, confinement of iodide ions in Mg-Beta zeolites (I@Mg-Beta) was successfully accomplished via the methodology of structural reconstruction, whose physicochemical property, channel connectivity as well as the location of Mg 2+ and I - ions were investigated systematically. It was found that Mg 2+ ions were located in the zeolitic framework and I - ions were mainly confined in Mg-Beta zeolite via the electrostatic interaction with tetraethylammonium cations. The establishment of structure–function relationship in CO 2 cycloaddition reaction with epoxides indicated the presence of synergistic effect between framework Mg 2+ ions and confined I - ions. The immobilisation of halide ions onto a zeolite support enabled it the recoverable ability from reaction systems, giving rise to relatively stable reusability. The catalytic transformation of CO 2 cycloaddition with epoxides in this work was devoted to ameliorate environmental stress from anthropogenic greenhouse gases of CO 2 by means of elaborately constructing metallosilicate zeolite confined non-metallic catalysts with dual functions.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Jiaguang Zheng,Xuezhang Xiao,Yan He,Man Chen,Meijia Liu,Shouquan Li,Lixin Chen
The Mg(BH 4 ) 2 -AlH 3 - x LiH ( x = 0, 0.5, 1) novel ternary composites have been synthesized through mechanical ball milling, their favorable dehydrogenation properties and mechanism have been experimentally investigated. It can be found that during ball milling, a slight amount of Mg(BH 4 ) 2 would react with LiH and transform into LiBH 4 , while most Mg(BH 4 ) 2 remained stable after ball milling. Two major dehydrogenation steps can be detected in the Mg(BH 4 ) 2 -AlH 3 - x LiH composite, which belong to the decomposition of AlH 3 and Mg(BH 4 ) 2 , respectively. Remarkably, the onset hydrogen desorption temperature of Mg(BH 4 ) 2 -AlH 3 - x LiH composite can be reduced to 125.9 °C, with a total hydrogen desorption capacity of 10.3 wt%. It is worth emphasizing that the reversible dehydrogenation capacity is obviously improved to 3.8 wt%, compared to the Mg(BH 4 ) 2 -AlH 3 composite. This reversible capacity can be held for 3 cycles without obvious degeneration. Microstructural analysis on de/rehydrogenated composite has identified the regeneration of [BH 4 ] - in Mg(BH 4 ) 2 -AlH 3 -0.5LiH composite and revealed the role of LiH in the cycling hydrogen desorption and absorption processes. The formation of LiBH 4 and MgH 2 resulted from the rehydrogenation between MgAlB 4 and LiH could be helpful for the stability of reversible hydrogen storage performance.
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2015
·Vol. 91
·期 4
·985-993
·
IF 2.349
Jiang Lu,Xiaodan Wei,Yu Chang,Shuanghong Tian,Ya Xiong
BACKGROUND An ozonation catalyst needs to be recycled easily and to exhibit high activity in view of its practical application in wastewater treatment. In this study, magnetic mesoporous MgFe 2 O 4 was successfully prepared and used as a new ozonation catalyst for degradation of Acid Orange II (AOII). The role of Mg in MgFe 2 O 4 was revealed to explain the high activity by catalytic experiments and XPS analysis. RESULTS The degradation efficiency of AOII in the MgFe 2 O 4 /O 3 process exceeds 90% over a wide pH range of 4.6–9.6, slightly affected by the solution pH. The catalytic activity of MgFe 2 O 4 is much higher than that of MgO, Fe 2 O 3 and also their mixture (MgO+Fe 2 O 3 ) with identical molar ratio of Mg 2+ to Fe 3+ , indicating the first role of Mg, i.e. coupling with Fe to present a synergistically catalytic effect. Furthermore, MgFe 2 O 4 possesses a reaction rate constant at least 2.3 times that of NiFe 2 O 4 , MnFe 2 O 4 , and CuFe 2 O 4 . It illustrates the second role of Mg, i.e. causing the high electron density on lattice oxygen in MgFe 2 O 4 indicated by XPS and thus favoring activation of the electrophilic ozone. CONCLUSIONS This study demonstrated the easy recycling and high activity of MgFe 2 O 4 in catalytic ozonation, and revealed the role of Mg in MgFe 2 O 4 . © 2015 Society of Chemical Industry
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·
IF 4.939
Xuelei Feng,Jianguang Yuan,Yujie Lv,Bogu Liu,Haixiang Huang,Bao Zhang,Youhua Yan,Shumin Han,Ying Wu
Magnesium borohydride (Mg(BH 4 ) 2 ) is an attractive materials for solid-state hydrogen storage due to its high hydrogen content (14.9 wt%). In the present work, the dehydrogenation performance of Mg(BH 4 ) 2 by adding different amounts (10, 20, 40, 60 wt%) of two-dimensional layered Ti 3 C 2 MXene is studied. The Mg(BH 4 ) 2 -40 wt% Ti 3 C 2 composite releases 7.5 wt% hydrogen at 260 °C, whereas the pristine Mg(BH 4 ) 2 only releases 2.9 wt% hydrogen under identical conditions, and the onset desorption temperature decreases from 210 °C to a relative lower temperature of 82 °C. The special layered structure of Ti 3 C 2 MXene and fluorine plays an important role in dehydrogenation process especially at temperatures below 200 °C. The main dehydrogenation reaction is divided into two steps, and activation energy of the Mg(BH 4 ) 2 -40 wt% Ti 3 C 2 composite is 151.3 kJ mol −1 and 178.0 kJ mol −1 , respectively, which is much lower than that of pure Mg(BH 4 ) 2 .
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高影响因子
Advanced Materials Interfaces
·
2020
·Vol. 8
·期 1
·2001606
·
IF 4.948
Zuohao Wen,Yujie Ke,Chengchen Feng,Shuliang Fang,Miuyang Sun,Xinghai Liu,Yi Long
The VO 2 -based smart windows can dynamically and reversibly adjust the indoor solar irradiation to reduce the energy consumption for building glasses. This paper reports the first successful preparation of Mg-doped VO 2 @ZrO 2 core−shell nanocrystals with promoted thermochromic performance as well as tunable appearance and wettability. The achieved combination of T lum of 52.4% and ∆ T sol of 7.1% is comparable to the best-reported results of VO 2 -based core−shell rod structures. The thickness of ZrO 2 shell is tunable between 3 and 14 nm, resulting in a slightly hydrophobic surface and a slight color change toward blue-green and brighter produced films. The preparation method based on hydrothermal and UV-curing methods is facile. This work may inspire future development of VO 2 synthesis, their structure−property, and the application the thermochromic films for energy-saving purposes in buildings or automobiles.
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DOI
高影响因子
Chemistry-An Asian Journal
·
2015
·Vol. 10
·期 11
·2452-2459
·
IF 4.587
Yuepeng Pang,Yongfeng Liu,Xin Zhang,Qian Li,Mingxia Gao,Hongge Pan
Herein, an initial attempt to understand the relationships between hydrogen storage properties, reaction pathways, and material compositions in LiBH 4 – x Mg(AlH 4 ) 2 composites is demonstrated. The hydrogen storage properties and the reaction pathways for hydrogen release from LiBH 4 – x Mg(AlH 4 ) 2 composites with x =1/6, 1/4, and 1/2 were systematically investigated. All of the composites exhibit a four-step dehydrogenation event upon heating, but the pathways for hydrogen desorption/absorption are varied with decreasing LiBH 4 /Mg(AlH 4 ) 2 molar ratios. Thermodynamic and kinetic investigations reveal that different x values lead to different enthalpy changes for the third and fourth dehydrogenation steps and varied apparent activation energies for the first, second, and third dehydrogenation steps. Thermodynamic and kinetic destabilization caused by the presence of Mg(AlH 4 ) 2 is likely to be responsible for the different hydrogen desorption/absorption performances of the LiBH 4 – x Mg(AlH 4 ) 2 composites.
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高影响因子
RARE METALS
·
2014
·Vol. 33
·期 1
·86-90
·
IF 0.806
Zhu Xi-Lin,Han Shu-Min,Zhao Xin,Li Yuan,Liu Bao-Zhong
Hydrogen storage properties of 2LiNH 2 –MgH 2 – x NbH ( x = 0 and 0.05) composites and the catalysis of NbH on hydrogen sorption reaction of the Li–Mg–N–H system were investigated. Hydrogen sorption properties of 2LiNH 2 –MgH 2 system are effectively improved by adding NbH. Temperature programmed desorption results show the addition of NbH reduces the dehydriding onset temperature of 2LiNH 2 –MgH 2 system by 21 K. Approximate 3.62 wt% hydrogen in 2LiNH 2 –MgH 2 –0.05NbH composite is released following a 500 min at 433 K, whereas the amount of hydrogen desorption is only ~3.16 wt% for the pristine system under the same condition. The sample with NbH exhibits higher dehydriding rate compared with the pristine one. Moreover, hydrogen absorption rate increases by adding NbH into the 2LiNH 2 –MgH 2 system. Hydrogen absorption capacity of the samples with NbH is 3.23 wt% within 400 min, which is higher than that of pristine sample. Fine NbH particles homogeneously distribute in the 2LiNH 2 –MgH 2 –0.05NbH composite, and catalyze the hydrogen sorption reaction rather than reacts as a reactant into new compound.
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高影响因子
NANO
·
2024
·
IF 1
Xiaoying Lin,Xiuchun Fan,Lifang Xu,Hao Lin,Qinhua Zhong
A porous carbon material (Mg-MOF-C) was prepared by carbonization in the N 2 atmosphere using Mg-MOF-74 as the precursor. Physicochemical properties of Mg-MOF-C materials were well characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FIRT), Thermogravimetric analyzer (TG), transmission electron microscope (TEM), energy dispersive spectrometer (EDS), N 2 adsorption/desorption isotherms (BET) and EDS. The adsorption properties of the products were studied Mg-MOF-C has a high specific surface area of up to 1739.29 m 2 /g, and the pore volume of micropores was 0.98 m 3 /g. Besides, 95% of the first adsorption is retained after five cycles. The adsorption processes agreed well with the pseudo-second-order kinetic model and Langmuir isotherm model.
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高影响因子
Journal of Building Engineering
·
2024
·
IF 6.7
Wenxin Wang,Shikun Chen,Xin Chen,Hao Qian,Yajun Zhang,Yi Liu,Dongming Yan
In this study, Mg–P coatings, prepared on steel alloy substrates, were exposed to temperature from 25 °C to 900 °C. The effects of high temperature exposure and the salt spray test on the anti-corrosion ability of Mg–P coating were investigated in detailed. The results show that the corrosion resistance of coatings decreases continuously from 25 °C to 700 °C, then increases at 900 °C of exposure. However, the corrosion resistance of coatings after 2000h salt spray test was significantly improved. In particular, the corrosion rate of the coating is only one-ninth that of the coating before the salt spray test when the temperature is 900 °C. Furthermore, the microscopic characterization test revealed that a dense oxide layer form between the steel alloy substrate and the coating when temperature exceed 400 °C. Besides the crystal phase transition and oxide layer , the synergistic effect of the secondary reaction of the raw material is the key factor to ensure that the coating still has good corrosion resistance at a high temperature.
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高影响因子
Nano Research
·
2018
·Vol. 11
·期 3
·1227-1237
·
IF 7.994
Zhang Hongchao,Meng You,Song Longfei,Luo Linqu,Qin Yuanbin,Han Ning,Yang Zaixing,Liu Lei,Ho Johnny C.,Wang Fengyun
Although In 2 O 3 nanofibers (NFs) are well-known candidates as active materials for next-generation, low-cost electronics, these NF based devices still suffer from high leakage current, insufficient on–off current ratios ( I on / I off ), and large, negative threshold voltages ( V TH ), leading to poor device performance, parasitic energy consumption, and rather complicated circuit design. Here, instead of the conventional surface modification of In 2 O 3 NFs, we present a one-step electrospinning process (i.e., without hot-press) to obtain controllable Mg-doped In 2 O 3 NF networks to achieve high-performance enhancement-mode thin-film transistors (TFTs). By simply adjusting the Mg doping concentration, the device performance can be manipulated precisely. For the optimal doping concentration of 2 mol%, the devices exhibit a small V TH (3.2 V), high saturation current (1.1 × 10 –4 A), large on/off current ratio (>10 8 ), and respectable peak carrier mobility (2.04 cm 2 /(V·s)), corresponding to one of the best device performances among all 1D metal-oxide NFs based devices reported so far. When high- κ HfO x thin films are employed as the gate dielectric, their electron mobility and V TH can be further improved to 5.30 cm 2 /(V·s) and 0.9 V, respectively, which demonstrates the promising prospect of these Mg-doped In 2 O 3 NF networks for highperformance, large-scale, and low-power electronics.
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高影响因子
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