JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Huilin Yi,Yujun Wang,Guangsheng Luo
Herein, we report a systematic investigation of the preparation of large-pore-volume Al 2 O 3 microspheres using a complex synthesis system with methylcellulose (MC) as the template and gelation initiator and organic solvents as the swelling agent and carrier medium under the flow characteristics of a coaxial microchannel. The adsorption of MC micelles on boehmite colloidal nanoparticles (NPs) was proven and determined by interfacial tension measurements, dynamic light scattering , and cryogenic transmission electron microscopy . Isothermal titration calorimetry demonstrated that the adsorption process was caused by nonspecific hydrophobicity ; one binding site was involved, and the affinity constant was 1060 M −1 . When the MC:NPs mass ratio exceeded 0.1, the template – NP bridged each other to form large aggregates, thereby forming large mesopores and enhancing the gelation speed. Alkanes, alcohols, and amines were applied to further enhance the porosity, and the swelling capacities were investigated experimentally and theoretically. Amines were efficient swelling agents owing to their excellent ability to swell MC micelles and insert into the acid colloid network. The coaxial microchannel was subjected to molding; this process significantly influenced the morphology and textural properties owing to the internal circulation during droplet formation. When trihexylamine with suitable steric hindrance , alkalinity , and polarity was used as the swelling agent, the microspheres exhibited an optimal specific surface area of 403 m 2 /g and a pore volume of 1.85 cm 3 /g.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Congqing Yang,Chao Gao,Hu Li,Mingxi Pan,Hui Huang
Silver-coated aluminum powder (Al/Ag) are anticipated to replace Ag powder in industrial production. However, the high activity of Al powder and insufficient understanding of the Ag deposition mechanism pose challenges in effectively controlling the Ag deposition process and morphology, thereby restricting which its applications. In this article, a diffusion-deposition competition mechanism is proposed to explain the growth path of Ag atoms on Al surfaces. This mechanism posits that the growth pathway of Ag atom is governed by the ratio between the surface diffusion rate and the deposition rate (V diffusion /V deposition ). Specifically, when surface diffusion dominates (V diffusion /V deposition ≫1), Ag atoms form a conformal layer, whereas the deposition-controlled (V diffusion /V deposition < 1 or V diffusion /V deposition ≪1), Ag atoms tend to form chains or clusters. Surface diffusion must be considered in regulation crystal growth process. By understanding this mechanism, Ag/Al particles with excellent electromagnetic wave (EMW) absorption properties (RL min = −37.8 dB, EAB max = 4.4 GHz) can be prepared simply by controlling only the experimental conditions that affect the surface diffusion and deposition rates. The insights gained from the proposed mechanism offer new ideas for the preparation of other noble metals or inorganic materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2024
·
IF 4.1
Chen Chang,Xuyang Wang,Xingyan Zeng,Yingfeng Wen,Hui Nie,Li Chang,Xingping Zhou,Xiaolin Xie,Lin Ye,Yiu-Wing Mai
The development of lithium-sulfur (Li–S) batteries is hindered by inhomogeneous Li plating and irreversible loss of active materials. In this work, a thermal conductive and electrocatalytic aramid nanofiber (ANF) composite separator containing surface-decorated alumina (Al 2 O 3 ) microspheres is prepared through a simple filtration approach using ZnO nanosheets decorated Al 2 O 3 microspheres (Al 2 O 3 @ZnO) as the thermal conductive filler and electrocatalyst. Compared with the separators fabricated by surface modification of commercial polyolefin separators, the as-prepared ANF/Al 2 O 3 @ZnO composite separator features homogeneous compositions and ensures uniform thermal distribution in both the through-plane and in-plane directions of the membrane. By rationally designing the structure of Al 2 O 3 @ZnO and adjusting the mass ratio of Al 2 O 3 @ZnO to ANF, excellent thermal conduction networks are formed by overlapping the ZnO nanosheets. Hence, the prepared ANF/Al 2 O 3 @ZnO composite separator possesses higher thermal conductivity than ANF/Al 2 O 3 composite separator, which benefits uniform thermal distribution and homogeneous Li plating within the battery. Moreover, the electrocatalytic ZnO nanosheets catalyze the conversion of lithium polysulfides, efficiently inhibiting the shuttle effect and improving sulfur utilization. When subjected to a temperature gradient, the ANF/Al 2 O 3 @ZnO composite separator assembled cells display high initial capacity, low decay rate, and superb cycle stability. This novel composite separator integrates both thermal conductive and electrocatalytic functional components with the heat-resistant ANF matrix, offering a new design strategy of separator towards high-performance Li–S batteries.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 7
·1603
·
IF 3.1
Yanfang Wu,Junjie Lan,Mingxuan Wu,Mingjun Wu,Li Tian,Hui Yang,Qijiang Li,Yue Li
The restoration of ancient ceramics has attracted widespread attention as it can reveal the overall appearance of ancient ceramics as well as the original information and artistic charm of cultural relics. However, traditional manual restoration is constrained due to its time-consuming nature and susceptibility to damaging ancient ceramics. Herein, a three-dimensional (3D) printing technique was employed to accurately restore Chinese Yuan Dynasty Longquan celadon using hollow Al2O3microsphere-modified 3D printing paste. The results show that the hollow Al2O3microsphere content plays a vital role in the printability, physical properties, and firing performance of the modified 3D printing paste. The printed green bodies show no noticeable spacing or voids under moderate rheological conditions. The as-prepared ceramic body modified with 6 wt.% hollow Al2O3microspheres and fired at 1280 °C exhibits optimal bending strength of 56.66 MPa and a relatively low density of 2.16 g∙cm−3, as well as a relatively uniform longitudinal elastic modulus and hardness along the interlayer. This 3D printing technique based on hollow Al2O3microsphere-modified paste presents a promising pathway for achieving non-contact and damage-free restoration of cultural relics.
研究领域:
材料科学
·
文物保护
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Surface Investigation
·
2023
·Vol. 17
·期 1
·202-207
·
IF 0.4
Iurina V. I.,Dudin A. N.,Neshchimenko V. V.,Mikhailov M. M.
Abstract The effect of a fluence of electrons with an energy of 30 keV in the range of (1–7) × 10 16 cm –2 on the concentration of color centers in micron-sized hollow particles of aluminum oxide is studied in comparison with bulk Al 2 O 3 microparticles. The analysis is carried out in situ according to diffuse reflection spectra in the range from 250 to 2500 nm. The radiation resistance of the studied microspheres is estimated relative to Al 2 O 3 microparticles from analysis of the difference spectra of diffuse reflection obtained by subtracting the spectra after irradiation from the spectra of nonirradiated samples. Changes in the difference spectra of diffuse reflection of aluminum-oxide microparticles and microspheres show that with an increase in the electron fluence, the induced absorption increases throughout the entire spectrum. It is established that the radiation resistance of aluminum-oxide microspheres to the action of electrons with an energy of 30 keV at a fluence of (1–7) × 10 16 cm –2 is greater than the radiation resistance of Al 2 O 3 microparticles. An increase in the radiation resistance of hollow aluminum-oxide particles is due to a low concentration of radiation-induced defects in the anion sublattice.
研究领域:
材料科学
·
辐射物理学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2015
·Vol. 40
·期 1
·589-595
·
IF 3.086
Hui Yang,Yuan Xie,Guisong Hao,Weiwei Cai,Xingzhong Guo
Porous alumina (Al2O3) microspheres with incontinuous multicavities have been successfully prepared via an oil-in-water (O/W) emulsion method accompanied by a sol–gel process in the presence of polyvinylpyrrolidone (PVP), sorbitan monooleate (Span 80) and ethyl acetoacetate (EAA). The introduction of PVP as a phase separation inducer into the oil phase of the O/W emulsion leads to the formation of incontinuous multicavities inside the microspheres, and the size of the cavities enlarges with the increase of the amount of PVP, while has no significant influence on the surface morphology and particle size distribution of the microspheres. EAA works as a chelating agent to ensure a spherical shape, and Span 80 acts as a stabilizer to preserve a smooth surface. An appropriate amount of PVP, EAA and Span 80 allow the formation of porous alumina microspheres with incontinuous multicavities. A preliminary mechanism based on phase separation for the structural evolution of alumina porous microspheres with multicavities is suggested. The spheres after heat treatment experience a phase transformation process in the following sequence: amorphous → γ-Al2O3 → α-Al2O3.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Tianyi Huang,Shafqat Ullah,Guangsheng Luo,Yujun Wang
The sol–gel technique combined with microfluidics is an effective approach for the preparation of microspheres. The formation and solidification of the sol can be influenced by the motion and extraction processes. The effects of extraction and motion were investigated using a real-time moisture content test, in situ observations, and CFD simulations. The microspheres retained their homogeneous internal structure with a narrow pore distribution when the extraction rate was less than 1 × 10 −4 ml/min·mm 2 , whereas extraction rates greater than 2 × 10 −4 ml/min·mm 2 resulted in clear hollows and stacking. A continuous phase devoid of extraction capability results in an internal hierarchy and bimodal pore size. Higher surface tension (greater than 4 mN/m) and lower fluid shear forces promoted high sphericity. These novel methods offer a promising approach for the preparation of alumina microspheres with a high spherical degree of 0.987 by matching the motion and extraction curing techniques.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2024
·
IF 4.5
Tianyi Huang,Zhiyuan Yu,Yujun Wang,Guangsheng Luo
Catalytic reactions play a central role in chemical production, wherein the strength of the catalyst support is key to long-term stable operation. Simple and efficient strength enhancement methods for heterogeneous catalysis have received significant attention. Herein, we developed a variable-temperature gradient elution technology for low-carbon alcohols to improve the crushing strength of microspheres prepared using the sol–gel method in a microfluidic system. Based on gel fiber growth and rearrangement utilizing the hydrogen-bonding effect between low-carbon alcohols and pseudo-boehmite, the pore structure and fiber network can be reconstructed. Low-carbon alcohols with strong hydrogen bonds and low steric hindrance are more conducive to the formation of short fibers when constructing a dense gel network coordinated with higher alcohols. By combining long and short fiber cross-linked networks, the crushing strength of microspheres is significantly improved, and a dense pore structure with a small pore volume forms. After gradient elution, a crushing strength of up to 71.78 N/mm 2 can be achieved with a high specific surface area of 254.27 m 2 /g, which significantly exceeds that of commercial alumina supports with the same pore volume. This efficient method provides an important solution for the long-term, stable operation of catalysts.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Fangyu Zhao,Ruihan Yang,Junxiang Ma,Yuan Gao,Yujun Wang,Guang sheng Luo
The efficient and economical removal of oxygenated compounds from Fischer-Tropsch synthetic oil is vital to the promotion of high-quality chemical development in the coal chemical industry. In this study, alumina microspheres with high specific surface area, high pore capacity, and small particle size were prepared. The adsorption thermodynamics, adsorption kinetics, and column adsorption experiments were systematically conducted on various fatty alcohols bearing different carbon numbers, in mixtures of α-olefins and alkanes with different carbon numbers. The competitive adsorption behavior between weakly polar, oxide-containing methyl acetate and 12-alcohols on an alumina surface was investigated to better reduce the actual system. The Freundlich model exhibited a better fit than the Langmuir model. The adsorption kinetics and proposed first-order kinetic equations fitted better to the Crank model. Comparing the adsorption effect of commercial alumina and the alumina microspheres prepared in this study, it was observed that a smaller particle size and larger pore volume reduced the internal and external diffusion resistance of adsorption, and a larger specific surface area provided more adsorption sites for the adsorption of the oxide-containing compounds. The competitive adsorption behavior of fatty alcohols and methyl acetate on the surface of γ-alumina was explored using a combination of density functional theory (DFT) calculations and experimental techniques. The results of this study can prove to be extremely useful for the efficient removal of oxide-containing compounds from Fischer-Tropsch synthetic oils.
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
Materials
·
2021
·Vol. 14
·期 16
·4712
·
IF 3.623
Fan Hu,Jun Gao,Biao Zhang,Fugang Qi,Nie Zhao,Xiaoping Ouyang
In this work, a new composite material with excellent dynamic impact resistance and outstanding quasi-static mechanical properties was synthesized. The composite material is composed of a polyurethane elastomer and a novel nano-polymer. The nano-polymer was composed of silane coupling agent-modified alumina microspheres and functionalized ionic liquids by double bond polymerization. The universal testing machine and split Hopkinson pressure bar were used to characterize the compression behavior, strength and energy absorption of the composite materials under static and dynamic conditions. Additionally, the comprehensive mechanical properties of polyurethane elastomer with different nano-polymer loadings (0.5–2.5 wt.%) were studied. The results show that whether it was static compression or dynamic impact, the polyurethane elastomer with 1% nano-polymer had the best performance. For the composite material with the best properties, its compressive yield strength under the static compression was about 61.13% higher than that of the pure polyurethane elastomer, and its energy absorption of dynamic impacts was also increased by about 15.53%. Moreover, the shape memory effect was very good (shape recovery is approximately 95%), and the microscopic damage degree was relatively small. This shows that the composite material with the best properties can withstand high compression loads and high-speed impacts. The developed composite material is a promising one for materials science and engineering, especially for protection against compression and impacts.Keywords:impact resistance;ionic liquid;nano-Al2O3;polyurethane elastomer
研究领域:
材料科学
·
工程力学
✓ 已验证
DOI
PubMed
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2019
·
IF 6.282
Linlin Ren,Xiaoliang Zeng,Xian Zhang,Rong Sun,Xingyou Tian,Yuping Zeng,Jian-Bin Xu,Ching-Ping Wong
Dielectric polymer composites consisting of inorganic fillers and polymers have wide applications in high energy density electronic devices. However, development of dielectric polymer composites with enhanced energy storage density and thermal conductivity is desired but challenge. Herein, we report polymer composites consisting of epoxy resin and silver nanoparticle-decorated Al 2 O 3 microspheres (Al 2 O 3 -AgNPs), which show enhanced energy storage density and thermal conductivity (1.11 W/m K), at 70 wt% Al 2 O 3 -AgNPs. The discharged energy density of Al 2 O 3 -AgNPs/epoxy resin composites with 70 wt% hybrid fillers is 4.28 × 10 -3 J cm −3 , while the composites without AgNPs is 3.09 × 10 -3 J cm −3 at 200 kV cm −1 . The enhanced energy storage density and thermal conductivity are attributed to the enhanced the interfacial polarization and the bridge role of AgNp in facilitating the heat flow across the interfacial boundary, respectively. The results support the potential applications of the Al 2 O 3 -AgNPs/epoxy resin composites used as dielectric materials in modern electronics and electric power systems.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Yanchun Wan,Huilin Yi,Yujun Wang,Guangsheng Luo
A novel and effective method is proposed to prepare uniform γ-alumina microspheres with large pore volumes using a coaxial microchannel. In this process, the so-called “temperature/pH-induced gelation” method, in which methylcellulose (MC) and hexamethylenetetramine (HMTA) are added to accelerate gelation of Al(OH)3 sol, is combined with microfluidics technology to ensure sphericity and dimensional homogeneity of the prepared microspheres. The influences of the sol concentration, the properties of pseudoboehmite (PB) used to obtain the sol, and the two-phase flow rates were investigated. By controlling the sol concentration at 10 wt % and the continuous to dispersed phase flow ratio at 14–50, 750–380-μm-diameter γ-alumina microspheres with uniform pore structures were synthesized using an Al(OH)3 sol obtained from PB3. The pore volume was 1.20 mL/g, and the crushing strengths were 8.19–16.67 N/mm2. Prepared at the maximum two-phase flow ratio, sample S9 exhibited the most uniform particle size of about 380 μm.
研究领域:
材料科学
·
化学工程
✓ 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）