DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 41
·18012-18018
·
IF 4.197
Yongfeng Liu,Yaxiong Yang,Xin Zhang,You Li,Mingxia Gao,Hongge Pan
The thermal dehydrogenation process of the KOH-containing Mg(NH2)2–2LiH system was systematically investigated by identifying changes in the structure and composition of its components by XRD and FTIR. During ball milling, the added KOH reacts with Mg(NH2)2 and LiH to produce MgO, KH and Li2K(NH2)3. During the initial heating process (<120 °C), the newly formed KH and Li2K(NH2)3 react with Mg(NH2)2 and LiH to yield MgNH, LiNH2 and Li3K(NH2)4 along with hydrogen release. Raising the temperature to 185 °C results in a reaction between Mg(NH2)2, MgNH and LiH that gives Li2Mg2N3H3 as the product and further releases hydrogen. As the temperature is increased to 220 °C, Li2Mg2N3H3 reacts with LiNH2 and LiH to produce Li2MgN2H2 and H2. Meanwhile, two parallel reactions between Li2Mg2N3H3, Li3K(NH2)4 and LiH also generate additional hydrogen. Specifically, the KH and Li2K(NH2)3, formed in situ during ball milling, serve as reactants in the dehydrogenation reaction of the Mg(NH2)2–2LiH system, which is responsible for the significantly improved thermodynamics and kinetics of hydrogen storage.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Lina Dai,He Wang,Yanduo Liu,Liru Cui
Direct light-driven methane selective conversion into useful chemicals remains a major challenge due to the need for photocatalysts with high photoactivity and selectivity in activating inert C-H bonds. In this study, we have developed highly photoactivity and selective photocatalytic CH 4 oxidation into C 2 H 6 using Ag-Mg tandem sites co-modified ultrathin ZnO hybrid photocatalysts in a flow reactor. Our system achieves an C 2 H 6 production rate of over 1860 μmol/g/h with 93 % selectivity, which is significantly higher than the efficiency of state-of-the-art photocatalytic systems. Various in-situ characterizations and theoretical studies reveal that the Ag-Mg tandem sites co-modified leads to enhanced photogenerated charge separation efficiency, while maintaining high ethane production rate owing to the strong selective adsorption capacity for methane and oxygen of the doped Mg sites and oxygen vacancy. Furthermore, the Ag nanoparticles cocatalyst can facilitate the removal of activated CH 4 in the form of methyl radicals in the gas phase, thereby promoting C 2 H 6 formation and inhibiting CH 4 overoxidation to produce CO 2 . Overall, these findings provide novel insights into the photocatalytic conversion of CH 4 on Ag/Mg-ZnO. These results offer valuable possibilities for developing more effective catalysts for the conversion of CH 4 to higher value-added products.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of the Australian Ceramic Society
·
2019
·Vol. 56
·期 2
·795-801
·
IF 0.692
Zhang Tao,Wei Yaowu,Chen Junfeng,Li Nan
In spite of the advantages of CaO refractories, such as high refractoriness, potential to produce pure steel molten, and high alkaline corrosion resistance, their application has been limited due to its poor hydration resistance. Introducing additives to improve the hydration resistance of lime is a novel method. The influences of Mg(OH) 2 and sintering temperatures on the sintering and hydration resistance of CaO aggregates that were produced by thermal decomposition were investigated in this paper. The purpose of this work was to produce high-purity CaO raw material with high density, low porosity, well grain growth, and good hydration resistance economically. The sintered samples were characterized by bulk density, apparent porosity, surface appearance, and microstructure. The results indicated that (1) Mg(OH) 2 promoted the grain growth of CaO, reduced the apparent porosity, and improved the density of the specimens. The hydration resistance of the samples was increased. (2) Increasing the sintering temperature improved the hydration resistance of the specimens obviously in the experiment. (3) Grain size of CaO was more uniform with the increment of Mg(OH) 2 content, and the density of the compacts was improved.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Applied Nano Materials
·
2023
·
IF 5.9
Xiaoqian Peng,Jing Zhang,Jinqiang Sun,Xiaochan Liu,Xinfu Zhao,Shimo Yu,Zhipeng Yuan,Sijia Liu,Xibin Yi
One of the most promising methods for capturing carbon dioxide (CO2) is solid physical adsorption, which is an efficient and simple technique. The key to effective CO2 capture is the development of high-performance solid adsorbents with excellent CO2 adsorption capacity, CO2/N2 selectivity, and rapid adsorption/desorption kinetics. In this paper, a Mg-MOF-74/sodium alginate composite aerogel was prepared by loading Mg-MOF-74 on sodium alginate sheets followed by directional freeze-drying. The composite aerogel exhibited a hierarchical porous structure, in which sodium alginate provided an open mesoporous/macroporous structure that promoted diffusion and contact with the active center of CO2. The Mg-MOF-74 micropores/mesopores promoted the strong interaction between CO2 and the adsorbent in the micropore and rapid mass transfer of CO2 to the adsorbent through the mesopores. The experimental data showed that MSA-6 achieved CO2 adsorption of 2.461 mmol·g–1 at 298 K. Furthermore, the CO2/N2 adsorption selectivity of MSA-6 reached 35.108, indicating its strong CO2 selective adsorption potential.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2024
·Vol. 36
·期 1
·1-14
·
IF 2.8
Han Xinghai,Song Guihong,Luo Di,Wu Yusheng,You Junhua
Mg 3 Bi 2 /Mg/Mg 2 Sn multilayer films with varying modulation periods were deposited on single crystalline Si substrate by alternating sputtering using high pure metal Mg, Mg 3 Bi 2 and Mg 2 Sn targets. The chemical and phase composition, surface and cross section image and thermoelectric performance of deposited films were observed, measured and studied. The results revealed that the deposited films were comprised of an evident layered structure containing the metal Mg, the Mg 2 Sn and the Mg 3 Bi 2 layer. The modulation period affected the carrier transport and thermoelectric properties of multilayer films. Carrier concentration, mobility, electrical conductivity and thermal conductivity of the multilayer films decreased with increasing heterogeneous interface, which severely scatter the carriers and phonon, reducing mobility and thermal conductivity. An increase in the Seebeck coefficient, power factor ( PF ), and thermoelectric figure of merit ( ZT ) was obtained by reducing modulation period. At room temperature, the film, which possessed the shortest modulation period of 677 nm, had a maximum ZT value of about 0.26. The carrier and phonon scattering processes were significantly strengthened by the more layer interface, enhancing the deposited film’s thermoelectric figure of merit.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 150
·期 6
·1591-1604
·
IF 2.372
Du Boyu,Chen Changzhou,Sun Yang,Liu Bingyang,Yang Yingying,Gao Si,Zhang Zhenshu,Wang Xing,Zhou Jinghui
Abstract Catalytic depolymerization of lignin to produce bio-oil, liquid fuels, and aromatic chemicals in high yields is important for a biorefinery to remain competitive. In this study, undoped and Ni-doped catalysts for depolymerization of rice husk lignin (RHL) were developed and analyzed. The results showed that the catalysts had hydrotalcite-like structures with lamellar morphology. With suitable Ni-doping amount, the catalysts had high activity, thus better promoted the depolymerization of RHL. Among all catalysts, the Ni1/4MgAl catalyst could best promote the cleavage of the β-O-4 aryl ether bond in RHL molecule and thus could substantially increase the yields of bio-oil. The depolymerization catalyzed by this catalyst was also found to be temperature-, time-, and solvent-dependent. This study provides information that can be beneficial to the biorefinery industries and may help promote the valorization of lignin. Graphic Abstract
研究领域:
生物质能
·
催化化学
·
可再生资源
✓ 已验证
产品关联
DOI
高影响因子
Journal of Sustainable Metallurgy
·
2023
·Vol. 9
·期 4
·1456-1465
·
IF 2.4
Li Hui-Fang,Li Li-Juan,Ji Lian-Min,Shi Dong
To develop a more stable and more efficient extraction system, a novel amide extraction system, containing extractant N , N -bis(2-ethylhexyl) acetamide (N523) and diluent diisobutyl ketone (DIBK), was proposed in this work. A series of operation conditions, such as the concentration of initial lithium in aqueous phase, the volume ratio of N523 and DIBK, phase ratio of O / A , the molar ratio of Fe/Li, were carried out. The lithium extraction rate reached up to 92% under the optimal extraction conditions. Considering the mass transfer of two phases and consumption of extractant, the three-stage counter-current extraction experiment was conducted. After 6 cycles experiment of the three stage counter-current extraction, the lithium extraction rate reached 99.89% and the separation factor of Li/Mg, Li/Na, Li/K, and Li/Ca were 103,300, 5288, 5233, and 760.4, respectively. The stoichiometry of the complex was LiFeCl 4 ·N523 by the slope method. The results indicated that N523-DIBK extraction system was effective to recovery of lithium from salt lake brine with high mass ratio of Mg/Li. Furthermore, the extraction thermodynamics study revealed lithium extraction was an exothermic process, which meant lower temperature promoted lithium extraction. Graphical Abstract
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2019
·Vol. 166
·期 4
·A658
·
IF 3.12
Zhenya Wang,Limei Sun,Wenyun Yang,Jinbo Yang,Kai Sun,Dongfeng Chen,Xiangfeng Liu
Li4Ti5O12 (LTO) has attracted great interest as an anode material due to the "zero strain" during Li+ insertion and extraction. But the intrinsic ionic diffusion coefficient and electronic conductivity are very poor. Herein, a strategy of Mg2+ and Zr4+ co-doping has been proposed to modulate the crystal structure and improve the electrochemical performances. More importantly, the synergic roles of Mg/Zr co-doping has been unveiled based on the analysis of X-ray diffraction, Neutron powder diffraction, X-ray photoelectron spectroscopy, and electrochemical measurements. Firstly, Mg-Zr co-doping expands the lattice parameter, cell unit volume and even Li-O bond length, which reduces Li+ migration barrier and benefits to Li+ insertion/extraction. Secondly, Ti-O shrinkage induced by Mg-Zr co-doping enhances the structure stability and subsequently the cycle performance. Thirdly, Mg-Zr co-doping promotes more Ti4+/Ti3+ which facilitates electron conductivity. Moreover, Mg-Zr co-doping also decreases the polarization and charge transfer impedance. Li3.8Mg0.2Ti4.9Zr0.1O12 delivers a discharge capacity of 180.5, 150.7, 110.4 and 78.9 mAh/g at 0.2C, 1C, 5C and 10C, respectively. Moreover, the capacity retention is greatly increased from 57.9% of LTO to 98.59% at 10C after 500 cycles.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Coatings
·
2024
·Vol. 14
·期 4
·383
·
IF 2.9
Chunling Xin,Shufen Hou,Lei Yu,Xiaojing Zhou,Yunkai Fu,Xiaoteng Yang,Weiwei Sun,Fan Yang,Xia Wang,Lili Liu
Yellow nanorod Mg-MOF-74 was obtained through a solvothermal synthesis method. The XRD, N2adsorption–desorption isotherms, SEM, and TGA results suggest that the particle size of Mg-MOF-74 reaches 400 nm after the introduction of sodium acetate in the precursor of Mg-MOF-74. Furthermore, the morphology of Mg-MOF-74 changed from cauliflower- to rod-shaped particles. At the same time, the BET specific surface area and pore volume of Mg-MOF-74 also increased a lot. Then, the CO2dynamic adsorption capacity of Mg-MOF-74 was measured with a self-made fixed bed at 30 °C and a 0.1 bar CO2partial pressure. The results show that the CO2adsorption capacity of Mg-MOF-74-N2 reaches 3.67 mmol/g, and its CO2adsorption capacity remains unchanged after 10 CO2adsorption–desorption cycles.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
·
2017
·
IF 3.101
Minwang Laipan,Haoyang Fu,Runliang Zhu,Luyi Sun,Rachel M. Steel,Sujuan Ye,Jianxi Zhu,Hongping He
Acid drainage (AD) poses a significant concern for water pollution due to its strong acidity and the toxicity of its various contaminants (e.g., heavy metal ions). In order to minimize the harmful effects of AD, the acidity must be neutralized and the contaminants be removed. The capacity of calcined Mg/Al layered double hydroxide (Mg/Al-CLDH) for simultaneously neutralizing the pH of AD and removing various heavy metal cations and oxyanions (Cr(VI) and phosphate) was studied herein. The interactions throughout co-removal between metal cations (in short M) and oxyanions were particularly investigated. In the solution with only M, Mg/Al-CLDH was capable of neutralizing solution pH and removing M. The reconstruction of LDH from Mg/Al-CLDH produced OH – to neutralize pH and partially remove M through precipitation. FT-IR results suggested that forming H-bonds with the reconstructed LDH (R-LDH) might also contribute to M removal. In the solution containing both M and oxyanions, M and oxyanions could mutually affect their removal efficiency by Mg/Al-CLDH. M weakened the removal capacities of Cr(VI) and phosphate, because it could compete for adsorption sites on R-LDH. Cr(VI) and phosphate showed complex effects on the removal of M: Low concentrations of Cr(VI) promoted the removal of M by providing extra adsorption sites; high concentrations of Cr(VI), however, had the opposite effect, as a high concentration of Cr(VI) might largely occupy the adsorption sites on R-LDH. By contrast, phosphate inhibited the removal of M considerably, which might be ascribed to its strong buffering ability that maintained a relatively strong acidic nature of the solution. Our results, for the first time, showed that Mg/Al-CLDH is particularly suitable for the treatment of AD containing various contaminants.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2013
·
IF 5.008
Chaoran Li,Zanyong Zhuang,Feng Huang,Zhicheng Wu,Yangping Hong,Zhang Lin
Treatment of wastewater containing low-concentration yet highly-expensive rare earth elements (REEs) is one of the vital issues in the REEs separation and refining industry. In this work, the interaction and related mechanism between self-supported flowerlike nano-Mg(OH)2 and low-concentration REEs wastewater were investigated. More than 99% REEs were successfully taken up by nano-Mg(OH)2. Further analysis revealed that the REEs could be collected on the surface of Mg(OH)2 as metal hydroxide nanoparticles (<5 nm). An ion-exchange model was proposed as a critical factor for both guaranteeing the reaction speed and maintaining the self-supported structure of the materials. In addition, a method was developed to further separate the immobilized REEs and the residual magnesium hydroxide by varying the solution pH. In a pilot-scale experiment, the REEs from practical wastewater were immobilized effectively at a high flow rate. We anticipate this work can provide a good example for the recycling of valuable REEs in practical industrial applications.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2016
·
IF 2.758
Weixuan Zeng,Xianfeng Yang,Minghui Shang,Xiewen Xu,Weiyou Yang,Huilin Hou
The tailored doping levels towards the band gap tunability are one of the challenges to push forward the potential application of one-dimensional (1D) ZnO nanostructures in the opto/electric nanodevices . In present work, we reported the exploration of Mg-doped ZnO nanofibers via electrospinning of polyvinylpyrrolidone (PVP), Zn(CH 3 COO) 2 (ZnAc) and Mg(CH 3 COO) 2 (MgAc), followed by calcination in air. The resultant products were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM), and X-ray photoelectron spectroscopy (XPS). The optical measurements (UV–vis) of the Mg-doped ZnO nanofibers suggested that the optical band gaps of the ZnO nanofibers could be tuned from 3.33 to 3.40 eV as a function of the Mg doing levels. This tunability of the band gap of ZnO nanofibers with an intentional impurity could eventually be useful for optoelectronic applications .
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）