RUSSIAN JOURNAL OF APPLIED CHEMISTRY
·
2015
·Vol. 88
·期 3
·529-532
·
IF 0.276
Shang Hongzhou,Zhang Xin,Zhao Jingdong,Liang Hongyu
Firstly, micro-particles Fe 3 O 4 /SiO 2 were prepared by sol-gel method, with nano-Fe 3 O 4 and tetraethoxysilane (TEOS) as original materials. Secondly, γ-aminoproplytriethoxysilane (KH-550) was used as couple agent to deal with the surface of micro-particles Fe 3 O 4 /SiO 2 , therefore amine was introduced to the surface of micro-particles Fe 3 O 4 /SiO 2 /KH-550. Finally, acrylamide (AM) and methyl methacrylic acid (MMA) as the functional comonomers, were grafted on the surface of micro-particles Fe 3 O 4 /SiO 2 /KH-550. The structures and properties of the magnetic particles were characterized by the fourier transform infrared spectroscopy (FTIR), X-ray diffraction analyzer (XRD), laser particle size analyzer, and vibrating sample magnetometer (VSM). The results shows that the characteristic peaks of Si-O-Si, KH-550, and P (AM-MMA) all were displayed in the infrared spectra, respectively. Surface modification of nano-particle Fe 3 O 4 does not affect its crystalline structure, and the grafting copolymers P (AM-MMA) were a crystalline polymer. The median diameter of Fe 3 O 4 /SiO 2 /KH-550/P (AM-MMA) is 72.46 um, whose size is larger than particles Fe 3 O 4 and Fe 3 O 4 /SiO 2 . Fe 3 O 4 and its derivatives remain super-paramagnetism, and the saturation magnetization reduced with the increasing the thickness of the modifying material on the surface of Fe 3 O 4 .
研究领域:
材料科学
·
化学工程
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DOI
高影响因子
Materials
·
2026
·Vol. 19
·期 5
·
IF 3.7
Zenghui Qian,Yangyang Yu,Wenjing Chen,Guodong Jiang,Yucai Shen,Zepeng Mao
Silica aerogel microspheres demonstrate tremendous potential as fillers for diverse materials across various fields. Enhancing the strength of silica aerogel microspheres is therefore crucial for their practical applications. This study aims to develop novel hydrophobic polymer-reinforced silica aerogel microspheres using water glass as the precursor, hexamethyldisilazane (HMDS) as the modifier, and styrene as the crosslinking agent, with further strength enhancement achieved through short-term thermal post-treatment. The effects of varying polystyrene coating levels, crosslinker dosage, and short-term heat treatment on the structure and properties of silica aerogel were investigated. The optimized silica aerogel microspheres (Sample A-6) exhibited a specific surface area of 604.8 m2/g and a thermal conductivity of 0.030 W·m−1·K−1and demonstrated excellent hydrophobicity and mechanical stability.
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DOI
PubMed
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Cheng Qian,Zhaocai Zhang,Yu Zhu
In this paper, a modification method for physical surface coating of Field's metal particles (FMP) using individual/combined polyvinyl alcohol (PVA) and nano-silica (NS) is proposed. The properties of cement pastes modified by FMP@H 2 O, FMP@PVA, FMP@PVA@NS, FMP@NS were evaluated by mechanical test, EIS, NMR, XRD, TG, and SEM. The results showed that the flexural strength and compressive strength of cement pastes with FMP@PVA, FMP@PVA@NS, FMP@NS at 7 days increased 2.74–13.01 % and 9.18–18.10 %, respectively, compared to the control samples, due to the inhibition of calcium hydroxide (CH) nucleation crystallization in the connection region between FMP and matrix by PVA, and CH reacting with NS to generate CSH gels. The cement paste with FMP@PVA has the best matrix strength at 28 days, resulting from the optimized connection region. Additionally, the mechanism of modified FMP strengthening connection region was proposed to explain the uniform distribution of FMP in fresh state, and the directional growth of CH crystals, which has a good agreement with the results of mechanical properties, phase analysis, thermal analysis and SEM observation. In accordance with the research in this paper, FMP as a new functional raw material is expected to be applied in the mix design of large-volume concrete, oil-gas well cement, and geothermal cement, especially used for temperature self-regulation and crack self-healing of cementitious materials.
研究领域:
材料科学
·
土木工程
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Meng-Jie Chang,Wen-Yao Zhu,Jun Liu,Ge Bai,Xin Li,Xiao-Qian Lu,Yu-Hong Lei
The separation of oil from wastewater and materials for oil absorption are highly demanded in the modern industrialization. For these purposes, silica aerogels with high hydrophobicity and surface aera and low density are promising candidates for oil absorption, but limited by the poor mechanical strength and structure stability during the usage. In this study, we presented a novel compressive silica aerogel by silica nanofiber (SNF) reinforcement and subsequent hydrophobic polyurethane strengthening via moisture curing (PSAG). The obtained PSAG exhibits unique core/shell fibrous reinforcement and prominent crosslinked network structure. The porous PSAG has a porosity of 81.06 % and density of 0.43 g cm −3 at solid content of 20 %. The hydrophobic PSAG shows an impressive sorption capacity towards CH 2 Cl 2 (11.2 g g −1 ), THF (5.5 g g −1 ) and acetone (3.8 g g −1 ), being able to separate 100 % of oils from an immiscible oil–water mixture. The PSAG shows exceptional resistance to acidic and alkaline conditions and has high flexibility and desirable reusability in repeatedly oil adsorption. Most importantly, the mechanical strength of SAG can be improved to 0.27 MPa of PSAG at prepolymer solid content of 20 %, and no cracking or deformation were observed after 50 cycles. Additionally, the PSAG shows impressive thermal insulation and flame retardancy performance in the air, which should have potential application as insulator for the solar evaporation for the purification of wastewater. This work provides new understanding and insight for further design and optimization of polyurethane-based reinforced aerogels.
研究领域:
材料科学
·
环境工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Ziyang Qiu,Zhengzheng Shi,Rui Li,Han Yan,Qian Chen,Liping Ruan
A carbon-silica nanomaterial for electromagnetic wave (EW) absorption was synthesized using a modified one-pot method. The unique hydrolysis-polymerization process forms a SiO 2 @SiO 2 /Carbon@Carbon core-shell structure. The growth process of the material was studied by transmission electron microscope (TEM) and thermogravimetric analysis (TGA). Nanoparticles were successfully synthesized with a core-shell structure after 6 h of reaction, and the composite material showed excellent EW absorption performance with a thickness of 3.8 mm. The minimum reflection loss (RL min ) was −56.3 dB, and the broadest effective absorption bandwidth (EAB) (RL ≤ 10 dB, 90% absorption) covered 5.15 GHz (12.48–17.63 GHz) with 1.8 mm of thickness. There is no significant difference in the EW absorption performance with increasing reaction time. Thus, this study provides a method for synthesizing EW-absorbing materials with shorter reaction time, simpler process, and excellent absorption properties, possibly a candidate for further application.
研究领域:
材料科学
·
电磁学
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DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 86
·45939-45945
·
IF 3.708
Wenjun Dong,Yan Cheng,Liang Luo,Xiaoyun Li,Lina Wang,Chunguang Li,Lifeng Wang
Hierarchical SiO2–QDs@SiO2 (QDs = CdTe, PbTe or PbS) nanostructures have been prepared by an integrated synthesis and self-assembly strategy using 3-mercaptopropionic acid (MPA) to stabilize the QDs and NaOH to control the self-assembly of QDs on the SiO2 nanobead carriers. 3–10 nm QDs covered with a 1–2 nm SiO2 shells were separately embedded on the surface of 50 nm SiO2 nanobead carriers, resulting in hierarchical SiO2–QDs@SiO2 nanostructures. MPA and NaOH played important roles in the nucleation and growth of QDs, etching the SiO2 nanobead carriers to the colloidal surface, and the self-assembly of the QDs on viscous SiO2 nanobead carriers. The hierarchical SiO2–QDs@SiO2 nanostructures possess various advantages: (I) the growth of QDs and their self-assembly on SiO2 nanobead carriers were performed in a one-pot reaction by a facile aqueous phase refluxing approach; (II) the SiO2 shell with 1–2 nm in thickness can prevent the leakage of toxic Cd2+ or Pb2+ and avoid photobleaching or environmental pollution; (III) the surface of hierarchical SiO2–QDs@SiO2 nanostructures can be easily functionalized through silane-coupling chemistry. Because of the excellent photoluminescence and biocompatibility, the hierarchical SiO2–QDs@SiO2 nanostructures modified by carboxyl (–COOH) active group can be available for covalent coupling to various biomolecules, which have shown potential applications in fingerprint detection and in vivo cell imaging.
研究领域:
纳米材料
·
材料科学
·
纳米技术
·
光致发光
·
生物成像
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法医学
·
胶体化学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2015
·Vol. 39
·期 8
·6474-6481
·
IF 3.086
Yansheng Liu,Wei Zhang,Xinlin Li,Xuanduong Le,Jiantai Ma
In this study, Pd nanoparticles functionalized on the surface of a Fe3O4@SiO2@m-SiO2 nano-catalyst has been synthesised with accessible active sites and ultra-large surface areas. The Pd/Fe3O4@SiO2@m-SiO2 nano-catalyst can be recovered by applying an external magnetic field. The catalytic activity of Pd/Fe3O4@SiO2@m-SiO2 is tested in the catalytic reduction of 4-nitrophenol and the hydrodechlorination of 4-chlorophenol. The high catalytic activity is attributed to the well-dispersed Pd nanoparticles on the ultra-large surface of Fe3O4@SiO2@m-SiO2. Furthermore, the Pd/Fe3O4@SiO2@m-SiO2 nano-catalyst can be reused at least five times without significant loss in activity, which confirms its good stability. Therefore, the approach mentioned above that is based on core–shell structured magnetic Pd/Fe3O4@SiO2@m-SiO2 provides a useful platform for the fabrication of Pd NP based catalysts that feature easy accessibility, superior activity and convenient recovery.
研究领域:
环境科学
·
材料科学
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DOI
高影响因子
ELECTROCHEMISTRY COMMUNICATIONS
·
2017
·
IF 4.396
Jie Zhang,Wensheng Tan,Yongxin Tao,Linhong Deng,Yong Qin,Yong Kong
SiO 2 nanospheres were synthesized by the sol–gel method using tetraethoxysilane (TEOS) as the precursor, which was then modified with 3-aminopropyltriethoxysilane (APTES) for the grafting of NH 2 to the SiO 2 surface. Au nanoparticles (AuNPs) were anchored to the NH 2 grafted SiO 2 , and then l -cysteine (L-Cys) templates were introduced to the SiO 2 /AuNPs through forming Au S bond. Another layer of SiO 2 was then coated on the L-Cys doped SiO 2 /AuNPs as the coating layer, and then the templates were removed by calcination to form a sandwich-structured molecularly imprinted SiO 2 /AuNPs/SiO 2 . Finally, the molecularly imprinted chiral interface was applied for electrochemical enantioselective recognition of Cys isomers, and discernible differences in the current signals could be observed on the differential pulse voltammograms ( I D-cys / I L-cys , 2.36).
研究领域:
分析化学
·
材料科学
·
电化学
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DOI
高影响因子
Crystals
·
2021
·Vol. 11
·期 10
·1165
·
IF 2.589
Tianju Chen,Peng Zhang,Guoliang Chen,Qi Yang,Feiming Li
Perovskite nanocrystals (PNCs) have witnessed unprecedented development in optoelectronic fields over the past few years. However, their intrinsic ionic structural instability still dramatically hinders their practical applications. Reliably improving the stability of PNCs while retaining their colloidal dispersity remains a grand challenge. Herein, we report a new strategy whereby CsPbBr3nanoparticles are grown in situ in an entropy ligand-functionalized SiO2nanoreactor. Consequently, the as-obtained CsPbBr3@SiO2NPs show outstanding stability and colloidal dispersity in various non-polar solvents and have good solution processability, which are unattainable by conventional template-assisted methods.Keywords:perovskites nanocrystals;SiO2nanoreactor;entropy ligands;colloidal dispersity
研究领域:
材料科学
·
纳米技术
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DOI
高影响因子
ACS Applied Nano Materials
·
2020
·
IF 0
Bo Wang,Shan Zhang,Bin Liu,Jinkai Li,Bingqiang Cao,Zongming Liu
CsPbBr3 perovskite quantum dots (QDs) have attracted great attention due to their different photoluminescent and electronic properties. However, the toxicity and low stability hinder their practical application. Here, low-toxicity Sn-substituted cesium lead bromide perovskite QDs were synthesized via the room temperature crystallization method. A phase transition of the perovskite quantum dots with the concentration of Sn increasing was found: the crystal phase of CsPbBr3:Sn perovskite QDs starts to be transformed into Cs4PbBr6:Sn perovskite QDs when the SnBr2 precursor exceeds 30 at. %. In this process, the controlled-color emission of perovskite QDs from green to blue can be realized. To improve the stability of quantum dots, CsPbBr3:Sn@SiO2 and Cs4PbBr6:Sn@SiO2 were synthesized via a simple one-step synthesis with hydrolysis of tetramethoxysilane in toluene solution containing perovskite QDs. The results show that CsPbBr3:Sn@SiO2 and Cs4PbBr6:Sn@SiO2 exhibited higher water stability and water solubility than pure QDs. In a mixed solution of toluene and water, the PL intensity of the CsPbBr3:Sn@SiO2 retained 46.7% and the Cs4PbBr6:Sn@SiO2 was 59.6% even after 24 h of reaction compared with the initial intensities. These quantum dots with good stability and luminescent property developed in this work are expected to be widely used in light-emitting diodes.
研究领域:
材料科学
·
纳米技术
·
光电子学
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DOI
CATALYSIS LETTERS
·
2014
·Vol. 144
·期 6
·1001-1008
·
IF 2.291
Lin Chao,Tao Kai,Hua Dayin,Ma Zhen,Zhou Shenghu
Abstract Bimetallic Au 3 M (M = Ni, Co, Fe) nanoparticles (NPs) were synthesized by reducing a mixture of Au 3+ and metal cations (Ni 2+ , Co 2+ , Fe 3+ ) by butyllithium in the presence of oleylamine. Au 3 M NPs were then deposited onto a commercial SiO 2 support. The Au 3 M/SiO 2 samples were not particularly active in the catalytic reduction of p -nitrophenol unless they were converted into Au–MO
x
/SiO 2 after appropriate thermal treatment in air. The Au–MO
x
/SiO 2 catalysts showed good thermal stability and significantly higher p -nitrophenol conversions than Au/SiO 2 . Relevant characterization was conducted employing X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and ultraviolet–visible spectroscopy. Graphical Abstract
研究领域:
催化化学
·
材料科学
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DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Fei Wang,Songyin Yu,Hui Xu,Junfeng Feng,Feihong Guo,Xiaoxiang Jiang,Jianchun Jiang
To solve the problem of harsh reaction conditions in lipid hydrogenation into fatty alcohol over Cu based bimetallic catalysts, the cheap Ni-base catalyst with high activity was synthesized. By using the hydrothermal method, the flower-like SiO 2 -ZrO 2 support was prepared. The Ni-Fe/SiO 2 -ZrO 2 catalyst was further prepared by the impregnation method and utilized in the fatty acid hydrogenation to produce fatty alcohol. Under the reaction conditions (240 °C, initial H 2 pressure: 2 MPa and reaction time: 3 h), the Ni-Fe/0.13SiO 2 -ZrO 2 catalyst attained 96.0% conversion and 86.4% fatty alcohol yield, much higher than that of Ni-Fe/ZrO 2 without SiO 2 (conversion 86.1% and fatty alcohol yield 61.9%). The high catalytic activity of Ni-Fe/0.13SiO 2 -ZrO 2 was ascribed to the increase of surface area, reduction of NiO grain size, and formation of flower-like morphology. The high selectivity to fatty alcohol over Ni-Fe/0.13SiO 2 -ZrO 2 was related to the increase of Lewis acidity (extra active sites) and the decrease of oxygen vacancy which weakened the adsorption of aldehyde (enol) on the catalyst and thus facilitated the formation of fatty alcohol.
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高影响因子
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