RSC Advances
·
2016
·Vol. 6
·期 80
·76867-76873
·
IF 3.289
Yunfei Zhang,Bo Yang,Jinhong Fan,Luming Ma
In this study, abrasives-reinforced metal matrix composites (MMCs) with a microscale size synthesized by ball milling (BM) could achieve highly active and stable dechlorination efficiency for aqueous 2-chlorophenol (2-CP). The preparation process of this composite via BM was optimized to obtain a high degradation efficiency, especially for the effect of the abrasives including B4C, SiC, α-Al2O3, SiO2, Fe3O4 and Na2SO4. The results showed that the hardness of the abrasives in the Fe-based MMCs was closely related with their dechlorination performance. Subsequently, the optimal abrasive, i.e. SiO2 was further investigated for its proper milling conditions with zero-valent iron (ZVI) particles including optimal SiO2 size, SiO2 loading, milling time, and the dosage of the process control agent (PCA). Additionally, the influence of other metal categories including Al and Si was also investigated for dechlorination; and their low reaction efficiencies were closely related with their passivating film. Finally, the longevity test suggested that the decreased reactivity of the SiO2–Fe MMC during the storage in air could be recovered when consecutively used, mainly due to the promoting effects of the inherent structure of SiO2–Fe MMC with the Fe/C and Fe/SiO2 interfaces, as well as the effective regeneration of the reactive sites by continuous iron dissolution.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2024
·Vol. 35
·期 12
·125601
·
IF 2.9
Xia Pu,Wanling Cai,Huayao Chen,Fujie Yang,Xiaomei Mu
The key step in preparing mesoporous silica is to remove the organic template agent, and the most common method used to achieve this goal is high-temperature calcination. However, this method has many disadvantages, one of which is that it reduces the silanol density on the surface of mesoporous silica, which affects its subsequent modification. Ionic liquids (ILs) are often used as extractants. In this work, the 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) IL is considered, and the effects of its concentration, reaction temperature, and reaction time as well as HCl concentration on the extraction rate and silanol density were investigated using an IL extraction template agent (cetyl trimethyl ammonium bromide (CTAB)). The results show that an IL concentration of 10%, a reaction temperature of 120 °C, a reaction time of 12 h, and an HCl concentration of 1% are the best reaction parameters; with these parameters, the extraction rate and the silanol density were found to be 93.19% and 2.23%, respectively. The silanol density of mesoporous silica treated by calcination is only 0.81%. A higher silanol density provides more reaction sites, so that the modified mesoporous silica treated with the IL can be loaded with more Zn ions.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2021
·
IF 3.498
Kai Su,Jiachengjun Luo,Yongjun Ji,Xingyu Jiang,Jing Li,Jianling Zhang,Ziyi Zhong,Fabing Su
Here we report the first synthesis of nearly pure-phase Cu 3 Si alloy that can be a highly efficient catalyst in the hydrochlorination of silicon reaction. This material was prepared by a high-temperature (1050 °C) calcination method in which copper and silicon powders were used as the reactants. The X-ray photoelectron spectroscopy (XPS) study revealed that the Cu and Si atoms in the Cu 3 Si alloy carried part of positive and negative charge, respectively. When employed as the catalyst in the silicon hydrochlorination to SiHCl 3 (TCS) for the production of Si polycrystals for Solar cell, the sample Cu 3 Si exhibited excellent low-temperature catalytic performance: the Si conversion and TCS selectivity respectively achieved 41.1% and 96.1% at 250 °C. Notably, its TCS yield at 250 °C was 1.2 times higher than that of the industrial catalyst-free system at 350 °C. Detailed analysis of the reaction process showed that the positively charged Cu atoms and negatively charged Si atoms in Cu 3 Si alloy could cleave the H–Cl bond in the reactant HCl and make the combination of H and Cl atom with Si atoms easier. Meanwhile, the reaction between the remaining Cu atom and Si was accelerated, leading to the generation of more active Cu 6.69 Si and ultimately superior catalytic performance. This work deepens the fundamental understanding of the hydrochlorination of silicon reaction, and provides an avenue for the synthesis of Si-based alloy catalysts .
研究领域:
材料科学
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化学工程
·
可再生能源
✓ 已验证
DOI
高影响因子
ADVANCED ENGINEERING MATERIALS
·
2022
·Vol. 24
·期 10
·2200125
·
IF 4.122
Xudong Yang,Mingrui Xie,Weiting Li,Junwei Sha,Naiqin Zhao
Silicon (Si) has a significant influence on the cellular structure and microstructure of the aluminum (Al) foams, which in turn will notably affect their mechanical responses. Herein, the Al–Si foams are fabricated via a novel powder metallurgy foaming approaches with multiple Si contents to investigate the role of Si concentrations on the structural and mechanical properties. The results show that the certain contents of Si can not only delay the expansion process, but also increase the maximum expansion rate to improve the cellular structure. Specifically, the AlSi7 foams process the optimal comprehensive compressive properties of yield stress (4.36 MPa), plateau stress (6.02 MPa), and energy absorption capacity (3.47 MJ m −3 ) with the relative density of 0.15. However, excessive Si can decrease the expansion rate and deteriorate the cellular structure. Moreover, the deformation mode of the Al foams during compressive process converts from plastic mode to brittle mode by the adding of Si. Generally, the AlSi7 foams possess an excellent trade-off between toughness and brittleness and exhibit the optimal mechanical responses.
研究领域:
材料科学
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机械工程
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2022
·Vol. 139
·期 45
·e53021
·
IF 3.057
Mingzhe Li,Bin Cao,Ruiqi Shang,Hongwei Mei,Liming Wang
Silicone rubber is used as an antipollution flashover material in outdoor insulation, which is susceptible to aging and has a shorter service life than other candidates. Microcracks are a common aging phenomenon that are difficult to be detected and repaired. The microcapsule self-healing technology can be used to repair microcracks and extend the service life of silicone rubber. This study considers hydrogen silicone oil as a representative of the polydimethylsiloxane healing agent system. Poly(urea–formaldehyde) microcapsules containing the hydrogen silicone oil are synthesized by in situ polymerization. The effects of the emulsifier concentration, initial pH value, initial ratio of the core–shell material, and sodium chloride (NaCl) concentration on the synthesis are investigated. Accordingly, the properties of the microcapsules before and after long-term storage are analyzed. The results demonstrate that microcapsules synthesized using poly(ethylene-alt-maleic anhydride) (EMA)+ polyvinyl alcohol (PVA) as the emulsifier have satisfactory morphology and performance, where the best synthesis conditions are 0.13 wt% EMA, 0.05 wt% PVA, initial ratio of the core–shell material of 1.5:1–2.0:1, initial pH value of 3.5–4.0, and 2 wt% NaCl. In long-term storage, the core material is well protected by the shell material. The synthesized microcapsule can serve as a material in the self-healing system of silicone rubber.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
TRIBOLOGY LETTERS
·
2022
·Vol. 70
·期 4
·1-11
·
IF 3.327
Liu Sisi,Deng Yuxing,Sun He,Jiang Shengqiang,Liu Jingang
A modified carbon nanotube composite film was designed and prepared by self-assembled molecular film technology. The carbon nanotubes modified by 3-glycidoxypropyltrimethoxy-silane (KH560) were grafted onto a silicon substrate by using N-3-(trimethoxysilyl)propylethyl-enediamine (DA) molecules as an intermediate connecting layer. Compared with the silicon surface, the surface wettability of the modified carbon nanotube composite thin film changes from super-hydrophilic to hydrophobic. At the nanoscale, the surface adhesion and friction forces decreased by nearly 91% and 87%, respectively, and at the microscale, the friction coefficient was reduced by 84%. The anti-wear lifetime is prolonged to 72 min under an applied load of 1 N, which is over 35 times longer than that of silicon. Due to the great wear-resistant properties of modified carbon nanotubes, they are expected to be widely used in micro/nanoelectromechanical systems.
研究领域:
材料科学
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纳米技术
·
表面工程
✓ 已验证
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2018
·
IF 2.488
Ting Zhou,Lunlun Gong,Xudong Cheng,Yuelei Pan,Congcong Li,Heping Zhang
The by-product silicon tetrachloride (SiCl 4 ) was usually obtained from polysilicon industry and was a cheaper alternative precursor. An economic method to produce silica aerogel using silicon tetrachloride under ambient pressure drying was presented in this work, which can also solve the pollution problem during the by-product silicon tetrachloride treatment process. The prepared aerogel samples were characterized by scanning electron microscopy, Brunauer-Emmett-Teller analysis, thermal conductivity analysis, contact angle test, Fourier transform infrared spectroscopy and thermogravimetric analysis . It was found that the molar ratio of H 2 O/SiCl 4 could affect the properties of aerogels seriously. The density and thermal conductivity first decreased and then increased as the molar ratio increased from 13 to 32. The porosity showed an opposite trend with the density. Silica aerogel with high specific surface area (856.7 m 2 /g), low density (0.077 m 3 /g) and low thermal conductivity (0.0213 W/m·k) were obtained at the optimal conditions when the molar ratio was 25. The resulting aerogel is also mesoporous material with super hydrophobicity and have a huge application in thermal insulation field.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Journal of Composites Science
·
2025
·Vol. 9
·期 1
·20
·
IF 3.7
Yuan La,Zengchao Wang,Junlin Zhu,Yao Yuan,Dexuan Cai,Fanghui Yin,Ximing Gao,Liming Wang
In recent years, transformer failures caused by the aging of bushing sealing materials have become increasingly common in power systems, posing significant risks to the safe and stable operation of transformers. Microencapsulated self-healing technology offers a promising solution by repairing microcracks and extending the service life of rubber sealing materials. This study developed polyurea-formaldehyde microcapsules encapsulating polydimethylsiloxane (PDMS) self-healing agents based on a Pt/PDMS curing system. A two-component microencapsulated self-healing system was further established for fluoro-silicone rubber materials. The feasibility of self-healing in these composite materials was validated through tensile property tests. Additionally, the effects of varying microcapsule contents and two-component ratios on material performance were systematically investigated, leading to the optimization of the mechanical and self-healing properties of the microcapsule/fluoro-silicone rubber composites. The results demonstrated that using SYLGARD™ 184 as the healing agent, with a two-component microcapsule ratio of 6:4 (A:B) and a microcapsule content of 10 phr, yielded a remarkable self-healing performance, achieving a healing efficiency of approximately 63%. The results of this paper can provide reference for the development of long-life rubber sealing materials.
研究领域:
材料科学
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高分子化学
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电力系统工程
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Zhuo Xing,Julong Song,Hong Pan
The zinc orthosilicate, Zn 2 SiO 4 ceramics, exhibit great potential as microwave dielectric materials due to their low dielectric constant and ultrahigh quality factor. The solid-state synthesis of Zn 2 SiO 4 ceramics often results in the presence of a secondary phase of ZnO, however, leading to significantly lower Q × f values. Cold-isostatic-pressing (CIP) and nonstoichiometry have been proven effective in purifying the Zn 2 SiO 4 but need elaborate process and composition manipulation. In this work, it was found that the particle size of SiO 2 plays a crucial role in purifying the Zn 2 SiO 4 phase. Specially, nano-sized SiO 2 particles (15 and 30 nm) led to the formation of a ZnO secondary phase in synthesized Zn 2 SiO 4 ceramics, while micro-sized (2 and 10 µm) resulted in pure-phase Zn 2 SiO 4 with excellent microwave properties. Notably, when prepared with 10 µm SiO 2 and sintered at 1 340°C, the resulting Zn 2 SiO 4 exhibited outstanding microwave performances with a Q × f value of 122 570 GHz, a temperature coefficient of frequency τ f of −51.9 ppm/°C, and a dielectric constant ( ε r ) of 6.5. These findings highlight the importance of controlling particle size during synthesis to achieve desired material properties such as purity and excellent microwave performances.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
Water
·
2024
·Vol. 16
·期 16
·2218
·
IF 3
Zhichao Chen,Yulin Min,Xin Zhao,Penghui Shi,Hongxiu Lu
Ceramsites are extensively employed as substrates for adsorbents in studies focused on phosphorus adsorption, leaving ceramsites crafted from diatomite less explored. Diatomite-based ceramsite, with its distinct porous architecture and surface silanol functionalities, is adept at supporting a variety of metal oxides, presenting a distinct advantage over other ceramsite variants. In light of this, the present study embarked on producing diatomite-based ceramsite using diatomite as the foundational material, subsequently enhancing it through the incorporation of Fe, thus yielding an Fe-modified diatomite-based ceramsite. Through adsorption testing, the modified ceramsite demonstrated a significantly improved adsorption capacity of 4.06 mg P/g, marking a substantial enhancement from the initial capacity of 0.9 mg P/g. The process of phosphorus adsorption exhibited a strong alignment with the Langmuir isotherm model and the pseudo-second-order kinetic model. In-depth analyses employing XRD, FTIR, zeta potential, and XPS techniques have revealed that the principal mechanisms driving the adsorption process are centered on interactions involving electrostatic forces, the formation of chemical precipitates, and the exchange of ligands. This investigation not only opens new avenues for the application of diatomite-based ceramsite but also lays down a theoretical foundation for its modification, thereby enriching the spectrum of its utility.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2020
·
IF 4.049
Yujie Zhang,Renling Lu,Ming Chen,Shouyong Zhou,Dabing Zhang,Haifeng Han,Mingliang Zhang,Hongdeng Qiu
An alternative method for efficient synthesis of urea-functionalized silanes was proposed on the basis of an N, N’ -carbonyldiimidazole-mediated acyl-transfer reaction between various amino-containing building blocks. The employment of different parent aminosilanes and alkylamines afforded an array of urea-containing silanes, which were subsequently immobilized onto silica gel to form corresponding urea-embedded alkyl stationary phases for high-performance liquid chromatography. The different substituents on the silicon core of the derivatized silane were found to significantly influence the final chromatographic behaviors. The comparative chromatographic characterization of thus-prepared silica packings with conventional octadecyl (C18) stationary phases revealed that the urea group was beneficial to suppress silanol activity towards basic probes, as well as to increase the water-compatibility of the alkyl stationary phases. The combination of a polar urea moiety and a non-polar long alkyl chain was favorable for an enhanced steric selectivity towards shape-constrained isomers. The polarizability-sensitive feature of such stationary phases made them good candidates for efficient separation of nitro-containing polar substances.
研究领域:
分析化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ORGANOMETALLIC CHEMISTRY
·
2025
·
IF 2.4
Zhiqing Liu,Zepan Sun,Haifeng Zhang,Yajing Pan,Pei Liu,Chonggang Wu,Tao Hu
Mussel inspired polydopamine (PDA) has been extensively applied as a linker in noble metal based heterogeneous catalysts to promote either metal dispersion or metal-support interaction. Herein, three heterogeneous Pt catalysts were first prepared by depositing Pt on PDA encapsulated porous silica (SiO 2 -PDA-Pt) with different PDA coating degree and their catalytic activity toward two model hydrosilylation reactions between methyldichlorosilane and a non-polar 1-octene and a polar allyl cyanide were investigated. Meanwhile, stability and recyclability of these catalysts were also explored. Results show that PDA coating degree may directly influence both Pt loading and its oxidation state, which then resultantly tailor the activity of the supported catalysts. The SiO 2 -PDA-Pt catalysts all showed excellent activity even after six catalytic rounds even though a gradual loss of Pt species were observed. Among them, the activity of the one with lowest PDA coating exhibited both higher activity and better recyclability, which is mainly ascribed to a higher content and retention of more active low valent Pt 0 species that may be well stabilized by proper PDA coating.
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
危险品化学品经营许可证（带存储）