COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Dongbo Zhu,Jihui Wang,Wenbin Hu
Hydroxyapatite (HA) bioactive film is a standard surface modification method for biodegradable Mg alloys . However, the corrosion resistance of HA film prepared before was mediocre, and the preparation process was complicated. In this study, hydroxyapatite film was prepared for the first time on layered double hydroxides (LDHs) coated Mg alloy by hydrothermal method . The structure and composition of LDHs and HA films were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The corrosion resistance and immersion behavior of the films in simulated body fluid (SBF) were investigated by using potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) techniques. The effects of different pH and calcium to phosphorus molar ratios (Ca/P ratios) of HA hydrothermal solution were investigated. The experimental results show that HA films appear in petal-like, filamentous and flower-like. The corrosion resistance of the film first increases and then decreases with the pH from weak acid to alkaline. With the increase of the Ca/P ratio, the film is gradually denser, and the protective effect is enhanced. The immersion test results show that after 7 days of immersion, the impedance modulus of the composite film is about 5 × 10 3 Ω·cm 2 , which is ten times higher than the single LDHs film. The effects of the pH and Ca/P ratio of the HA hydrothermal solution on the preparation of HA film are simply explained by thermodynamic theory. The Mg-LDHs-HA composite film provide a corrosion protection barrier for Mg substrate and HA film is biologically active. The barrier effect and the mineralization behavior provide a better corrosion protection for Mg substrate.
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高影响因子
POLYMER
·
2022
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IF 4.432
Qisong Lin,Feng Gao,Yongjun Wang,Wangyang Lu,Wenxing Chen
Antimony-free poly(ethylene terephthalate) (PET) has been synthesized through polycondensation of p -phthalic acid and ethylene glycol , and then subjected to a viscosity-increasing process by liquid-state polycondensation (LSP). For both of these processes, a novel environmentally benign ethylene glycol-soluble Ti/Mg bimetal (TM) catalyst has been used. The structure of the TM catalyst has been comprehensively characterized and its catalytic activity in the polycondensation reaction has been evaluated and compared with those of other titanium-based catalysts. The results reveal that the TM catalyst is a chelated complex with high catalytic activity for polycondensation to afford PET without significant side reactions. Indeed, the LSP process catalyzed by TM affords a PET product with high intrinsic viscosity suitable for industrial yarn production (1.08 dL/g) within 60 min, and that exhibits higher thermostability with increasing intrinsic viscosity. Finally, the kinetics of the TM-catalyzed polycondensation has been probed based on the variation of intrinsic viscosity with increasing polycondensation time.
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高影响因子
APPLIED CATALYSIS A-GENERAL
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2021
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IF 5.706
Yankai Liu,Ruinian Zhou,Jianyu Qu,Feng Han,Shuai Zhang,Xingliang Xu
Upgrading carbon dioxide (CO 2 ) into valuable products is a highly promising strategy of artificial carbon cycle. In this study, a series of in situ reduced CuMgAl layered double hydroxides (R-CuMgAl-LDHs) composites were synthesized, in which Cu nanoparticles were effectively dispersed and anchored on MgAl-LDHs with formation of Cu + and Cu 0 species. The optimized R-Cu 1.5 Mg 1.5 Al 1 -LDH exhibited excellent catalytic performance for the carboxylative cyclization of 2-methyl-3-butyn-2-ol with CO 2 (turnover number of 243) under mild conditions. The layered structure of LDH stabilized the active Cu species with high dispersion, enhancing the catalytic efficiency of this carboxylative cyclization reaction. Simultaneously, the dual-activation of both CO 2 and propargylic alcohol by Cu 0 /Cu + species generated on the surface of LDH contributed significantly to the catalytic efficiency enhancement. Furthermore, R-Cu 1.5 Mg 1.5 Al 1 -LDH catalyzed the reaction of a wide range of terminal or internal propargyl alcohols with CO 2 , yielding various functionalized α-alkylene cyclic carbonates. Finally, a reasonable reaction mechanism was put forward according to the comprehensive analysis.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
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IF 13.273
Mewin Vincent,Venkata Sai Avvaru,Maciej Haranczyk,Vinodkumar Etacheri
Despite of their inexpensive and sustainable characteristics, practical application of Mg-Na hybrid batteries are limited due to the lack of high performance dual-ion compatible cathode materials. This is mainly due to the increased size of Na-ions and improved electrostatic repulsion resulting from the high charge density of Mg-ions. Herein, we report for the first time a fast charging and ultralong-life Mg-Na hybrid battery based on an extremely pseudocapacitive hierarchical bronze TiO 2 (TiO 2 -B) nanosheet cathode. This two dimensional cathode exhibited outstanding pseudocapacitance (up to 94%), specific capacities (195 mAh/g @ 25 mA/g), rate performance (140 mAh/g @ 1A/g), cycling stability (∼76% after 6000 cycles @ 1A/g), coulombic efficiency (∼100%) and fast-charging (∼8 min). These performances are vastly superior to the previously reported metal oxide type Mg-Na hybrid battery cathodes. Mechanistic investigations revealed Mg-Na dual-ion intercalation pseudocapacitance with no significant structural changes. Exceptional electrochemical performance of the TiO 2 -B nanosheet cathode is credited to the dominant pseudocapacitive Mg-Na dual-ion diffusion through the nanointerfaces resulting from the hierarchical microstructure of TiO 2 -B nanosheets. High surface area, ultrathin nature and mesoporous structure are also contributed as secondary factors by facilitating superior contact with the electrolyte solution. The demonstrated method of nanointerfaces induced pseudocapacitive Mg-Na dual-ion intercalation provides new opportunities for the development of high-performance Mg-Na hybrid batteries.
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高影响因子
CHEMICAL PHYSICS LETTERS
·
2021
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IF 2.328
Guanfeng Tian,Youqing Wu,Shiyong Wu,Sheng Huang,Jinsheng Gao
In 2 O 3 , MnO/In 2 O 3 , and MgO/In 2 O 3 catalysts are synthesized by the co-precipitation method and investigated for CO 2 hydrogenation to methanol. The introduction of Mn and Mg oxides dramatically enhances the CO 2 adsorption capacity of In 2 O 3 . The changing trend of methanol selectivity is consistent with the CO 2 adsorption capacity. MnO/In 2 O 3 and MgO/In 2 O 3 catalysts show higher methanol selectivity compared with that of In 2 O 3 .
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高影响因子
TRIBOLOGY INTERNATIONAL
·
2023
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IF 6.2
Chen Zhao,Xingwei Wang,Chuanpeng Li,Yu Liu,Shuang Sun,Shuangshuang Yang,Yuchen Sun,Zhenjun Peng,Qiangliang Yu,Meirong Cai,Bo Yu,Feng Zhou,Weimin Liu
Sodium dodecyl sulfate (SDS) and 8-Hydroxyquinoline (8-HQ) intercalated layered double hydroxides (LDH) sheets were in-situ formed in MAO layer to prepare a composite coating (CI@LDH-MAO) on AZ31 magnesium alloy . This composite coating demonstrates commendable anti-corrosion performance, primarily attributed to the formation of LDH sheets and insoluble Mg(HQ) 2 compounds. The electrochemical impedance modulus of the composite coating surpasses that of the MAO coating by three orders of magnitude after immersion of 360 h. Concurrently, the CI@LDH-MAO composite coating exhibits exemplary tribological properties, characterized by a friction coefficient of approximately 0.19 and a wear rate of (11.5 ± 1.5)× 10 −6 mm 3 /(N·m). This outstanding tribological performance can be ascribed to enhanced interaction of lubricants with the friction interface by 8-HQ and SDS anions.
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高影响因子
CORROSION SCIENCE
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2021
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IF 7.205
Jinlong Chen,Jianxin He,Lingjie Li
To gain insights into the effect of sodium dodecylbenzene sulfonate (SDBS) on Mg corrosion in NaCl medium, in-situ Raman spectroscopy was employed to monitor the interface evolutions of Mg surface in NaCl and NaCl+SDBS solutions. Accompanied by ex-situ Raman, SEM and XPS results, the evolution models during Mg corrosion in corrosive media were established to reveal the influence of DBS − . Competitive adsorption models about the interface of Mg/NaCl+SDBS between DBS − and Cl − were also presented to explain the inhibition effect of SDBS. These models guide the optimal usage of SDBS in Mg alloy corrosion inhibition.
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高影响因子
CELLULOSE
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2020
·Vol. 28
·期 1
·301-316
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IF 4.21
Yang Cong,Yuan Jun,Guo Yi,Luo Xiaogang
In this work, Mg/Al layered double hydroxides embedded phosphorylated cellulose microspheres (Mg/Al LDH@PCMs) were prepared first with solid-phase phosphorylation on CMs then in situ nano-assembly between Mg 2+ , Al 3+ and phosphate groups. Hence the synthesis degree of Mg/Al LDH was enhanced. The obtained Mg/Al LDH@PCMs were characterized by scanning electron microscopy (SEM), specific surface area test (BET), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), ζ potential, X-ray electron energy (XPS). The novel in situ nano-assembly method provided improved Mg/Al LDH load without compromising the porous structure of CMs, making Mg/Al LDH@PCMs suitable for water treatment. The Mg/Al LDH@PCMs adsorbed tetracycline hydrochloride (TC) with a kinetic pattern of pseudo second-order kinetic model, while isothermally fitted with the Freundlich isotherm model. The maximum theory adsorption capacity of Mg/Al LDH@PCMs q m was 25.107 mg g −1 with the Gibbs free energy ∆G = 7.523 kJ mol −1 under 298 K. The TC removal mechanism was deeply investigated via characterization results and also the batch experimental results, it was inferred that electrostatic attraction between LDH particles and the anion species mainly dominated the adsorption process. These properties make Mg/Al LDH@PCMs have a wide application prospect in the water purification field.
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高影响因子
RENEWABLE ENERGY
·
2020
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IF 6.274
Hui Yong,Xin Wei,Jifan Hu,Zeming Yuan,Ming Wu,Dongliang Zhao,Yanghuan Zhang
A composite catalyst Fe@C was successfully prepared by chemical blowing and carbonization method, at the same time its defect level, pore distribution and specific surface area were investigated. In addition, the Mg–Ce–Y + x wt.% Fe@C ( x = 1, 3, 6, 10) composites also were synthesized by mechanical ball-milling. The effect of the Fe@C content on hydrogen absorption and desorption property of the Mg–Ce–Y alloy was characterized by XRD, SEM , TEM, PCI , and DSC method. The activated composites exhibit an excellent absorption and desorption kinetic performance, which attributeed to the efficient catalysis of Fe@C composite catalyst. The Mg–Ce–Y + 6 wt % Fe@C composite exhibits the fastest hydrogen absorption/desorption kinetics and relatively lower decomposition temperature and it can absorb 90% of the maximum hydrogen capacity within 2 min and only takes 12 min to release the same amount of hydrogen under 300 °C. Besides, the dehydrogenation activation energy is reduced to 84.9 kJ/mol and the initial hydrogen release temperature is less than 250 °C, which is owing to the outstanding synergistic catalyst effect of Fe@C on Mg-based hydrogen storage alloy . However, the thermodynamic properties of the composites have not been improved, of which the enthalpy change is 80.6 kJ/mol.
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高影响因子
APPLIED CLAY SCIENCE
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2020
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IF 4.605
Yaowu Cao,Qinghai Guo,Mengsi Liang,Weihao Sun
Antimony enrichment in aquatic environments is of great concern to international community. High-temperature geothermal waters usually contain excessive Sb, which are apt to contaminate the groundwaters or surface waters used as drinking waters in and around a hydrothermal area. However, Sb removal from geothermal water is rarely documented and the effect of high temperature on Sb removal has not received much attention. In this study, batch sorption experiments were conducted to investigate Sb removal from water by a hydroxyl-intercalated, mechanochemically synthesized Mg-Fe-LDH (i.e. Mg-Fe-OH-LDH) capable of avoiding secondary pollutions commonly related to other Mg-Fe-LDH intercalated by undesirable anions, such as Cl − and NO 3 − . The sorption capacities of Mg-Fe-OH-LDH for Sb(III) and Sb(V) were up to 48.7 and 30.0 mg/g, respectively. Notably, Mg-Fe-OH-LDH performed even better in removing aqueous Sb(V) at higher temperatures, superior to sorption of Sb by iron oxides that is generally exothermic and tends to be inhibited by increasing reaction temperature. The removal of Sb(V) existing as Sb(OH) 6 − by Mg-Fe-OH-LDH was attributable to its exchange with interlayer hydroxyl, and therefore could be impaired to some degree by coexisting anions with stronger electronegativity or smaller ionic radii . In contrast, anion exchange didn't contribute so much to Sb(III) sorption, because the main Sb(III) species at pH < 10 is neutral Sb(OH) 3 . XPS analyses confirmed that inner-sphere complexation between sorbed Sb(III) and Fe on Mg-Fe-OH-LDH layers was formed, which was hardly affected by competitive anions. Mg-Fe-OH-LDH is promising to be practically applied in removing both Sb(III) and Sb(V) from contaminated natural waters, wastewaters, or geothermal waters potentially acting as a pollution source .
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2020
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IF 4.65
Jiahao Wang,Yang Li,Ruizhi Wu,Lin Xu,Zhen Zhang,Jing Feng,Jinghuai Zhang,Legan Hou,Yunlei Jiao
Mg-Li matrix composite containing Ni 0.4 Zn 0.4 Co 0.2 Fe 2 O 4 (NZCF) was fabricated by multi-layer composite rolling (MCR). Anti-electromagnetic interference composites with multi-scale microstructure were obtained, in which Mg-9Li alloy serves as the reflecting layer and NZCF particles serve as the absorbing layer. The microstructure, electrical conductivity , magnetic property , and electromagnetic interference (EMI) shielding property of the composites were investigated. The results show that, with the increase of NZCF content, the electrical conductivity of the composites decreases, the magnetic property increases, and its shielding capability increases. The electrical conductivity and magnetic property of the composites can be regulated and controlled by adding nano-scale Ni-Zn-Co ferrites, which provides an efficient strategy for producing metal matrix composites with high EMI property.
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高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2020
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IF 3.408
Si Li,Dakui Zhao,Huili Wang,Yu Zhang,Wenjiang Huang,Ying Zhou
The valence electron structure (VES) of MoSi 2 -based solid solution alloys was studied herein by the bond length difference (BLD) method based on the empirical electron theory (EET) of solids and molecules and the average atomic model. Compared to those for a MoSi 2 alloyed with Al or Mg separately, alloying with Mg + Al together significantly decreased the bond energy of the main bond branch and the ratio of the number of covalent valence electrons to the total number of valence electrons in the Mo(Si 0.92 Al x Mg 0.08- x ) 2 solid solutions and increased the lattice electrons. Thus, alloying MoSi 2 with Mg + Al together reduced the hardness and strength of MoSi 2 and increased its fracture toughness above what occurred when Mg or Al were added separately. The combined impact of the impurities was especially noticeable when MoSi 2 was alloyed with 4 at% Mg+4 at% Al. Based on those results, Mo(Si 0.92 Al x Mg 0.08- x ) 2 solid solution alloys were made, their mechanical properties were tested, and the experimental results were consistent with those of the theory.
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高影响因子
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