Gas Science and Engineering
·
2023
·
IF 0
Guanhua Zhang,Shaocong Mo,Hongtao Xu,Xiaoyu Yan,Binlin Dou,Guomin Cui,Qiguo Yang,Wei Lu
Metal-organic frameworks (MOFs) are popular crystalline materials owing to their high porosity, tunable pore structure, and large surface area. By introducing a carboxylic acid to compete with 2,5-dihydroxyterephthalic acid for magnesium ions in solution, a crystal defect method was used to prepare multi-level pore Mg-MOF-74 with an unregular framework structure of Mg-MOF-74 in this paper. In the prepared samples, the adsorption amounts varied in descending order with various carboxylic acid species: Mg-MOF-74-Propionic acid (37.95 cm 3 /g STP) > Mg-MOF-74 (15.46 cm 3 /g STP) > Mg-MOF-74-Acetic acid (9.19 cm 3 /g STP) > Mg-MOF-74-Formic acid (7.81 cm 3 /g STP). At 1.5 kPa, the CO 2 adsorption of 2,5-dihydroxyterephthalic acid and propionic acid with a ratio of 2:1 can reach 2.78 cm 3 /g STP (standard temperature and pressure) with the comparison to 0.47 cm 3 /g STP of pristine Mg-MOF-74. Under atmospheric pressure, the adsorption capacity of modified Mg-MOF-74 can reach 37.95 cm 3 /g STP, equivalent to 2.45 times of the original Mg-MOF-74.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
Science China-Chemistry
·
2010
·Vol. 53
·期 7
·1497-1501
·
IF 0
Ma Hong,Nie Xin,Cai JiaYing,Chen Chen,Gao Jin,Miao Hong,Xu Jie
The catalytic oxidation of biomass-derived polyhydroxyl compounds provides an efficient and green route for biomass resource utility. Gold nanocrystals supported on Mg(OH) 2 were synthesized by sol-immobilization method, characterized by XRD, TEM, UV-vis DRS, and tested in the selective oxidation of 1,2-propanediol to lactic acid. The gold particle size and the ratio of Au to 1,2-propanediol strongly influenced the catalytic activity. Over Au/Mg(OH) 2 with the majority of gold particles concentrated in 14–18 nm, excellent catalytic performance with 94.4% conversion and 89.3% selectivity to lactic acid has been achieved under 0.3 MPa O 2 at 60 °C for 6 h.
研究领域:
化学工程
·
环境科学
·
催化科学
✓ 已验证
产品关联
DOI
Catalysts
·
2020
·Vol. 10
·期 5
·485
·
IF 3.52
Ming Zhang,Zhen Song,Mengquan Guo,Xiangxiang Li,Yanjun Lin,Lihong Zhang
The effect of reduction atmospheres, H2/N2, C3H8/H2/N2, C3H8and CO, on the structure and propane direct dehydrogenation performance of PtIn/Mg(Al)O/ZnO catalyst derived from ZnO-supported PtIn-hydrotalcite was studied. The physicochemical properties of the as-prepared and used catalytic system were characterized by various characterization methods. The results show that the dehydrogenation performance, especially the stability of the PtIn/Mg(Al)O/ZnO catalyst, was significantly improved along with the change in reduction atmosphere. The highest catalytic activity (51% of propane conversion and 97% propylene selectivity), resistance toward coke deposition, and stability for more than 30 h were achieved with the H2/N2-reduced catalyst. The optimal dehydrogenation performance and coke resistance are mainly related to the high Pt dispersion and In0/In3+molar ratio, strong Pt–In interaction and small metal particle size, depending on the nature of the reduction atmospheres. The reconstruction of meixnerite favors the stability and coke resistance to some extent.Keywords:propane dehydrogenation;reduction atmosphere;coke deposition;meixnerite;PtIn/Mg(Al)O/ZnO
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2020
·
IF 2.779
Yanying Bi,Hang Yang,Xiaohan Yun,Hang Zhang,Xiangjie Ma,Guogang Li,Yujun Liang,Yongjun Chen
Currently, the development of highly efficient emission tunable phosphor materials is necessary for improving the lighting quality of UV light based white emitting diodes (WLEDs). Herein, a series of new blue-emitting Ca 7 (Mg, Zn) 2 P 6 O 24 : Eu 2+ (CM/ZP: Eu 2+ ) phosphors were successfully synthesized through a high temperature solid phase reaction process. Interestingly, through constructing Ca 7 (Mg, Zn) 2 P 6 O 24 : Eu 2+ solid solutions based on a complete substitution of Mg 2+ by Zn 2+ , the controllable blue-shift emission from 441 to 418 nm could be realized. This result could be attributed to the selective occupation of different Ca 2+ ions for Eu 2+ ions due to distortion of coordination polyhedron. The corresponding full width at half maximum (FWHM) exhibits a gradual narrowing from 66 to 27 nm after [Zn→Mg] replacement, and the color purity of Eu 2+ emission in Ca 7 Zn 2 P 6 O 24 (CZP) could reach 93.2%. Finally, the thermal quenching resistance of the as-prepared Ca 7 (Mg, Zn) 2 P 6 O 24 : Eu 2+ phosphors show remarkably excellent performance. Moreover, the thermal stabilities working at 150 °C of CMZP: Eu 2+ were gradually improved from 71% for CZP: Eu 2+ to 97% for CMP: Eu 2+ of original photoluminescence intensity. Generally, the cation substation induced selective occupation of Eu 2+ to control FWHM is an efficient design to achieve emission-tunable phosphors, and the developed narrow-band Ca 7 (Mg, Zn) 2 P 6 O 24 : Eu 2+ blue-emitting phosphors could serve as potential blue phosphors for WLEDs application.
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
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Xin Song,Fangjun Shao,Zijiang Zhao,Xiaonian Li,Zhongzhe Wei,Jianguo Wang
Precise regulation of reaction selectivity at high conversions is the key to non-terminated alkyne semi-hydrogenation. Herein, a support modification strategy was employed to incorporate trace amounts of Mg elements into alumina support. The modified support loaded Pd catalyst optimized the activity and selectivity of the non-terminated alkyne semi-hydrogenation reaction. The TEM and XRD characterization of the catalysts demonstrated the entry of Mg elements into the Al 2 O 3 lattice to achieve the modification of the support. For the 2-butyne-1-ol semi-hydrogenation reaction, the Pd 0.5 /Mg 1 @Al 2 O 3 catalyst showed 99 % conversion and 97 % selectivity of the cis product at hydrogen pressure of 0.1 MPa and 25 °C. The introduced Mg element changed the electronic structure of Pd nanoparticles in the catalyst. The precise regulation of the 2-butyne-1-ol semi-hydrogenation reaction was achieved by adjusting the ratio of Pd 0 to Pd 2+ using the synergistic effect of Pd 0 and Pd 2+ .
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Haifei An,Weijian Tian,Xin Lu,Huanmei Yuan,Liyun Yang,Hao Zhang,Haoming Shen,Hao Bai
Adsorbents with high adsorption capacity and high selectivity are crucial for carbon capture, utilization and storage (CCUS) technology applied to industrial flue gas to reduce carbon emissions. In this paper, a defect-rich hierarchical porous Mg-MOF-74 was synthesized successfully with MgCl 2 ·6H 2 O used as a metal source considering that the weak coordination of Cl − may interfere with the normal coordination process of metal centers and organic ligands, which causes the formation of crystal defects. Through the analysis of a series of characterizations, ligand deletion of Mg-MOF-74 prepared with MgCl 2 ·6H 2 O was confirmed, and the deleted ligand was estimated to be approximately 20% compared with the traditional Mg-MOF-74 prepared with Mg(NO 3 ) 2 ·6H 2 O, which led to mesopores accounting for 36.9%, and the width of mesopores reached 13.1 nm. Compared with traditional Mg-MOF-74, the adsorption heat of CO 2 at zero load of the defect-rich hierarchical porous Mg-MOF-74 increased from 36 kJ·mol −1 to 46 kJ·mol −1 , and the saturated adsorption capacity of CO 2 under ambient pressure was improved by 15%. Interestingly, the IAST selective adsorption performance of CO 2 /N 2 was increased by 20 times. Compared with the saturated adsorption capacity for traditional Mg-MOF-74, the equivalent adsorption capacity of hierarchical porous Mg-MOF-74 only needs 17 kPa, indicating that it is suitable for carbon capture operation in a real flue environment. Calculations of density functional theory (DFT) confirmed that the active site of the hierarchical porous Mg-MOF-74 has a lower adsorption energy with CO 2 due to the presence of defects, which is regarded to play a key role in improving the CO 2 capture performance.
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
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Lingxia Wu,Feifei Yang,Kai Niu,Jian Zhao,Xiong Zhang,Xianbo Lu,Xuning Li,Yanqiang Huang,Jiping Chen
Bisphenol compounds [bisphenol A (BPA), etc.] are one class of the most important and widespread pollutants in food and environment, which pose severe endocrine disrupting effect, reproductive toxicity, immunotoxicity, and metabolic toxicity on humans and animals. Simultaneous rapid determination of BPA and its analogues (bisphenol S, bisphenol AF, etc.) with extraordinary potential resolution and sensitivity is of great significance but still extremely challenging. Herein, a series of single-atom catalysts (SACs) were synthesized by anchoring different metal atoms (Mg, Co, Ni, and Cu) on N-doped carbon materials and used as sensing materials for simultaneous detection of bisphenols with similar chemical structures. The Mg-based SAC enables the potential discrimination and simultaneous rapid detection of multiple bisphenols, showing outstanding analytical performances, outperforming all other SACs and traditional electrode materials. Our experiments and density functional theory calculations show that pyrrolic N serves as the adsorption site for the adsorption of bisphenols and the Mg atom serves as the active site for the electrocatalytic oxidation of bisphenols, which play a synergistic role as dual active centers in improving the sensing performance. The results of this work may pave the way for the rational design of SACs as advanced sensing and catalytic materials.
研究领域:
环境科学
·
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED ENERGY
·
2020
·
IF 8.848
J. Yan,Z.H. Pan,C.Y. Zhao
Thermochemical heat storage uses a reversible chemical reaction to store thermal energy. This thermal energy storage method has high energy density and allows long-term thermal energy storage. MgO/Mg(OH) 2 is a promising reversible reaction for thermochemical heat storage systems. The performance of this reversible reaction inside a reactor plays a key role in its practical applications. The direct type heat transfer reactor is a novel design compared with an indirect powder bed reactor. It allows the gaseous heat transfer fluid to flow through the powder in order to break the heat transfer limitation from the heat exchanger between the MgO/Mg(OH) 2 powder and the heat transfer fluid. In this study, we evaluated the performance of a direct type MgO/Mg(OH) 2 reactor under various operating conditions. Parametric analyses indicated that the heat output is limited by the reaction rate rather than the heat transfer efficiency. Results also showed the best bed thickness in order to achieve the highest temperature output. Material characterization indicated that the MgO/Mg(OH) 2 particles did not agglomerate with each other after 15 heat charging and discharging cycles.
研究领域:
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Progress in Natural Science-Materials International
·
2017
·
IF 2.038
Xuezhang Xiao,Teng Qin,Yiqun Jiang,Fulei Jiang,Meng Li,Xiulin Fan,Shouquan Li,Hongwei Ge,Qidong Wang,Lixin Chen
Mg(AlH 4 ) 2 nanoparticles with a particle size less than 10 nm have been successfully synthesized by mechanochemical method using LiAlH 4 and MgCl 2 as raw materials together with LiCl buffering additive. In comparison to Mg(AlH 4 ) 2 microparticles, Mg(AlH 4 ) 2 nanoparticles exhibit a faster hydrogen desorption kinetics and lower desorption temperature. The hydrogen desorption temperatures of the first and second dehydrogenation steps are 80 and 220 °C for the Mg(AlH 4 ) 2 nanoparticles, which are about 65 and 60 °C, respectively, lower than those of Mg(AlH 4 ) 2 microparticles. The decomposition activation energy is reduced from 135 kJ/mol for Mg(AlH 4 ) 2 microparticles to 105.3 kJ/mol for Mg(AlH 4 ) 2 nanoparticles. It is proposed that the shortened diffusion distance and enhanced diffusivity of Mg(AlH 4 ) 2 /MgH 2 nanoparticles provide an energy destabilization for lowering the dehydrogenation temperature, and thus being the key factor for promoting the hydrogen desorption kinetics. More importantly, it is demonstrated that the dehydrided nano MgH 2 hydride with a particle size below 10 nm can be formed after rehydrogenation process, resulting in the good cycling hydrogen desorption performance of nano MgH 2 .
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Longgong Xia,Kai Wang,Hongjun Wang,Zhihong Liu
Thermodynamic studies of the Mg-Te-O system have significant importance in improving Te recovery from pyrometallurgical processes and materials preparation in related fields. Ternary compounds, Mg 3 TeO 6 , Mg 2 Te 3 O 8 , MgTe 2 O 5 and MgTe 6 O 13 , in the Mg-Te-O system have been synthesized in the present study, and their decomposition behaviors at various atmospheric conditions have been experimentally studied with the TGA-DSC technique. Obtained results showed that: 1) Mg 3 TeO 6 started to decompose to MgO , TeO 2 , and O 2 at 1255.9 °C in the carrying gas of 20% O 2 - 80% Ar, and the initial decomposition temperature decreased along with decreasing oxygen concentration in the gas; 2) Mg 2 Te 3 O 8 decomposed to MgO and TeO 2 , and when the O 2 was rich in the gas, Mg 3 TeO 6 was also found in the product. The initial decomposition temperature of Mg 2 Te 3 O 8 was 832.1 °C, 839.2 °C, and 839.9 °C, when the O 2 concentration in the carrying gas was 20%, 0.1%, and 0.0001%, respectively; 3) The decomposition products of MgTe 2 O 5 were same with that of Mg 2 Te 3 O 8 , and its initial decomposition temperature decreased along with decreasing the O 2 concentration in the gas; 4) MgTe 6 O 13 decomposed to MgTe 2 O 5 and TeO 2 around 700 °C, and the initial decomposition temperature decreased with decreasing O 2 concentration in the gas. Along with increasing temperature, MgTe 2 O 5 converted to Mg 3 TeO 6 through oxidation reactions, and Mg 3 TeO 6 decomposed at elevated temperatures.
研究领域:
材料科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
CLAYS AND CLAY MINERALS
·
2021
·Vol. 69
·期 4
·434-442
·
IF 1.609
Zhang Mingzhu,Sun Shiyong,Lv Rui,Golubev Yevgeny Aleksandrovich,Wang Ke,Dong Faqin,Kotova Olga Borisovna,Kotova Elena Leonidovna
Lipase is an industrial enzyme, the catalytic efficiency of which is restricted by various environmental factors. To improve this efficiency, immobilization technology has been utilized in the past to improve the stability of lipase in harsh conditions. Immobilization technology can be divided into physical methods and chemical methods. Some unsolved problems remain in current immobilization technology. The interaction between enzyme and immobilization support is weak and reversible during physical adsorption, resulting in poor stability of the immobilized enzyme and the contamination of substrate solution by leached enzymes. In chemical methods, enzyme-active sites might be inactivated due to the chemical reactions between enzyme molecules and support, resulting in a decrease in the enzymes’ catalytic activity (Liu et al., 2018a ). The objective of the current study was to construct a nanostructured lipase via Mg-amino-clay as a carrier and improve the catalytic activity and stability of lipase by immobilization. Lipase produced by Aspergillus oryzae was immobilized on aminopropyl functionalized magnesium phyllosilicate (a 2:1 trioctahedral talc-like silicate Mg-amino-clay) via a 1-(3-Dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) coupling agent. The physical and chemical properties of the Mg-amino-clay and Mg-amino-clay-based nanostructured biocatalyst (Mg-clay-lipase) were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Optimal immobilization conditions were determined by taking into account the following variables: amount of initial lipase, EDC concentration, and reaction time. The results revealed that the optimum temperature, pH, and thermal stability of Mg-clay-lipase were greater than equivalent values for free lipase under optimal conditions (described below – Process for Immobilization of Lipase on Mg-amino-clay ). The Michaelis-Menten constant (K m ) values were 5.25 mM and 7.42 mM while the maximum reaction rates ( v max ) were 30.58 mM/(L·min) and 55.87 mM/(L·min) for free lipase and Mg-clay-lipase, respectively. The present study provided a new nanostructured biocatalyst and demonstrated that the enzyme activity and stability of Mg-clay-lipase were superior to those of free lipase due to the mechanism of 'interface activation'.
研究领域:
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
KEY ENGINEERING MATERIALS
·
2017
·
IF 0
Meng Xia Qian,Jian Li Ma,Min Hong Xu
A novel supported catalyst is prepared through immobilization of water soluble phthalocyanine, which is synthesized by modifying tetraminophthalocyanine with cyanuric chloride, onto the supporting material Mg-Al hydrotalcite via co-precipitation method. The structure of the catalyst is characterized by infrared spectroscopy instrument (FT-IR) and X-ray diffractometer. Catalytic activity is examined through comparative experiments. The results show that it exhibits high catalytic activity for degradation of methylene blue (MB) in the presence of H2O2, the remaining rate of MB is 12.02% after 6 h. The reaction process conforms to the equation of pseudo-first-order kinetics, and the correlation coefficient R2> 0.99. The recycling tests for five times are also carried out and prove its reusability in catalytic application.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
危险品化学品经营许可证（带存储）