ACS Applied Materials & Interfaces
·
2019
·
IF 8.456
Zhe Qu,Lin Yao,Jing Li,Junhui He,Jie Mi,Shihui Ma,Siyao Tang,Lili Feng
Thermochromic vanadium dioxide (VO2) as one of the most promising candidates for smart windows has attracted widespread attention in recent years. Excellent optical performances (luminous transmittance, Tlum, and solar modulation efficiency, ΔTsol) of VO2-based coatings are usually pursued as crucial issues. In the current work, we report an ingenious approach for the synthesis of VO2@SiO2 dual-shell hollow nanospheres (DSHNs) and the preparation of DSHNs thermochromic coatings. A sequential bifunctional template-induced mechanism for the formation of DSHNs was proposed. Because of the unique hollow-core and dual-shell structure, the as-prepared VO2@SiO2 DSHNs coatings exhibited appealing optical performances with enhanced luminous transmittance of 61.8% and solar modulation efficiency of 12.6%, compared with continuous and dense VO2 coatings. It has been proved that the improvement of visible transmittance could be ascribed to the effective reduction of refractive index (from 2.6 to 1.6 at 630 nm). In addition, its excellent thermochromic performance has been confirmed by the model cubes measurements, expressing a great potential as energy-efficient smart windows in high-rise buildings. The bifunctional template-induced synthetic strategy may inspire more facile, efficient and inexpensive processes for development of well-defined multishelled hollow nanostructures for varied applications.
研究领域:
材料科学
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2021
·Vol. 36
·期 2
·174-182
·
IF 0.957
Shi Minxian,Tang Qingxiu,Fan Shanshan,Dong Chuang,Huang Zhixiong
The ceramifiable polymer composite of MgO-Al 2 O 3 -SiO 2 /boron phenolic resin(MAS/BPF) with 40wt% of inorganic fillers was calcined at 1 200 °C for different time to promote ceramification of ceramifiable composite and improve heat resistance. The effects of different calcine time on the macroscopical morphology, mass loss, phase evolution, microstructure and chemical bond evolution of MAS/BPF composites were characterized by XRD, XPS, and SEM analyses. The experimental results reveal that the increase of calcine time result in the fewer holes, relatively denser and smoother top layer of MAS/BPF composites and protect the interior from deeper decomposition. The final residues of composites are amorphous carbon and C-O-Si-Al-Mg ceramic. And MAS/BPF composites show excellent mass stability, low shrinkage and self-supporting features after 2 h holding compared with BPF composites without 40wt% of inorganic fillers.
研究领域:
材料科学
·
无机化学
✓ 已验证
DOI
高影响因子
ADSORPTION SCIENCE & TECHNOLOGY
·
2017
·
IF 0.754
Jin Lin,Yan Wu,Afshin Khayambashi,Xiaolong Wang,Yuezhou Wei
The silica-based CeO2 adsorbent (CeO2/SiO2) was prepared for removing fluoride from the aqueous solution. The synthesized adsorbent was characterized by scanning electron microscope, energy dispersive spectrum, X-ray diffractometer, Fourier transform infrared spectrometer, and zeta potential measurement analyses. The adsorption batch experiments in the various experimental conditions including solution pH, contact time, initial fluoride concentration, and adsorption temperature were performed and investigated. The maximum adsorption capacity of fluoride into CeO2/SiO2 was 2.441 mmol/g at pH 3 and 298 K. The adsorption kinetics and isotherms were well described by the pseudo-second-order model and the Langmuir model, respectively. The fluoride adsorption reached the equilibrium in 15 min from the aqueous solution with the initial fluoride concentration of 400 mg/l at 298 K. In the temperature range of 298–338 K, the maximum adsorption capacity of fluoride decreased from 2.441 mmol/g to 2.109 mmol/l at pH 3. The adsorption thermodynamics study revealed that this process was a spontaneous, exothermic, and entropy-driving adsorption. Furthermore, the mechanism of adsorption was identified as the anion exchange and the electrostatic interaction. The desorption efficiency of fluoride-loaded CeO2/SiO2 adsorbent could reach about 95% by 0.1 mol/l NaOH.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
NANO
·
2020
·
IF 1.566
Mengfan Liang,An’ni Yang,Yan Zhu,Shuhong Sun
In this paper, the effects of SiO 2 size (ranging from 5.7 Å to 7.50 Å) and shape (spherical, cylindrical and rod) on the interface structure and the thermodynamic performance of polyimide (PI)/SiO 2 composites were investigated by molecular dynamics simulation. Also, whether the nanofiller with isocyanate propyl triethoxysilane (ICTOS) can highly enhance interaction in PI/SiO 2 (bonded PI/SiO 2 ) was investigated by experiment. To enhance the interfacial intensity efficiency, the coupling agent ICTOS was used to modify the surface of the silica nanoparticle. The results showed that the size and shape of SiO 2 not only affect the interfacial number of hydrogen bonds and the interfacial area, but also impact on the glass transition temperature of the composites. As the radius of the embedded nanosilica increased, the bonded energy and T g gradually decreased, showing a prominent filler size effect. At the same time, the T g of spherical-type system was significantly greater than the nanosystems of other shapes. This is because as the number of surface atoms and superficial area of the spherical filler are higher than the nanofillers of other shapes, the combination between spherical-type silica and the PI chains is more compact than those between cylindrical and rod-like silica and the PI chains. The contributions of different nanofillers to the filler size dependency of T g of the nanocomposites can be elucidated by comparing the interfacial interaction and net structure between the PI matrix and silica which exhibit prominent filler shape and size dependency. Finally, the results were confirmed by the nonbonded interaction energy and reduced radial distribution function (RRDF), and the highly interaction interface is found to bring about a greater reinforcing effect.
研究领域:
材料科学
·
热力学
·
界面化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2018
·Vol. 22
·期 11
·3475-3484
·
IF 2.509
Wang Hang,Li Xiaojie,feng Xi,Liu Ya,Kang Weimin,Xu Xianlin,Zhuang Xupin,Cheng Bowen
A novel approach is proposed to prepare a proton-conductive nanochannel membrane based on polyvinylidene difluoride (PVDF) porous membrane with modified SiO 2 nanospheres. The hydrophilic PVDF porous membrane with a 450-nm inner pore size was chosen as the supporting structure. Pristine SiO 2 with a uniform particle size of 95–110 nm was synthesized and functionalized with –NH 2 and –COOH, respectively. Through-plane channels of porous membrane and arranged functional nanoparticles in pores could contribute to constituting efficient proton transfer channels. The characteristics such as morphology, thermal stability, water uptake, dimensional swelling, proton conductivity and methanol permeability as proton exchange membranes, of the SiO 2 nanospheres, and the composite membrane were investigated. The formation of ionic channels in membrane enhanced the water uptakes and proton conduction abilities of the composite membranes. PVDF/Nafion/SiO 2 –NH 2 exhibited superior proton conductivities (0.21 S cm −1 ) over other samples due to several proton sites and the acid–base pairs formed between –NH 2 and –SO 3 H. Furthermore, all the composite membranes exhibited improved methanol resistance compared with Nafion. Therefore, such a design based on porous membrane provided feasibility for high-performance proton exchange membrane in fuel cell applications.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
Micro & Nano Letters
·
2019
·Vol. 14
·期 9
·976-979
·
IF 0.975
Wen Zeng,Qiqi Yang,Bin Shao,Donglin Guo,Chunhong Li,Yilong Ma,Xueguo Yin,Sibo Zhao,Kejian Li
The monodisperse Fe@SiO 2 core-shell nanocapsules were synthesised via hydrothermal reaction followed with heat treatment. Nanostructures were characterised by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The magnetic properties of Fe@SiO 2 nanocapsules were evaluated with magnetic property measurement system. The results show that Fe@SiO 2 core-shell nanocapsules are highly monodispersed. The silica thickness of Fe@SiO 2 nanocapsules increased from 10–20 to 25–35 nm with increasing tetraethyl orthosilicate (TEOS) amount. In the Fe@SiO 2 nanocapsules prepared with 900 μl TEOS, as the reaction temperature increases, the mean particle size of Fe@SiO 2 nanocapsules increases from 328 to 546 nm. It is remarkable that the saturation magnetisation of Fe@SiO 2 nanocapsules decreases with increasing silica thickness. However, the coercivity of nanocapsules has less influence with the variation of silica thickness and particles’ length.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2015
·
IF 3
Zhuoxing Wang,Jiang Xu,Yunjun Hu,Heng Zhao,Junliang Zhou,Yu Liu,Zimo Lou,Xinhua Xu
A selective adsorbent for Hg(II) was prepared by coating Fe 3 O 4 nanoparticles with SiO 2 which was further functionalized with thiol (–SH) group. The new adsorbent (Fe 3 O 4 @SiO 2 -SH) was shown to adsorb aqueous Hg(II) species in a wide range of pH (1.0–8.0) conditions. The Hg(II) adsorption capacity q e was more than 90.0 mg g −1 at pH > 3.0, and was slightly decreased to 84.6 mg g −1 under strong acidic conditions due to the electrostatic repulsion. The Langmuir isotherm model fitted the adsorption data better than the Freundlich, Temkin, and Dubinin-Radushkevich isotherms models. The maximum adsorption capacity of Fe 3 O 4 @SiO 2 -SH for Hg(II) was 132.0 mg g −1 . The adsorption kinetics were shown to follow the pseudo-second-order kinetic model, and the kinetic constant k 2 was 2.4 × 10 −3 g mg −1 min −1 . The magnetic retrieve of the newly-developed adsorbent was easily carried out via an external magnetic field, enabling both excellent adsorbent utilization and adsorption efficiency at high Hg(II) concentrations.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ENERGY CONVERSION AND MANAGEMENT
·
2018
·
IF 6.377
Yalin Zhu,Yaosong Qin,Chengsha Wei,Shuen Liang,Xuan Luo,Jianhua Wang,Lin Zhang
Organic-inorganic hybrid materials are promising for encapsulation of phase change materials (PCMs) to achieve exceptional capsule properties. In this work, novel polymer-SiO 2 hybrid shelled nanoencapsulated PCMs (NanoPCMs) were fabricated in one-pot, through sequentially executed interfacial hydrolysis-polycondensation of alkoxy silanes and radical polymerization of vinyl monomers. The morphologies, chemical compositions, and crystal structures of the NanoPCMs were characterized by SEM, TEM, FT-IR, and XRD methods. The thermal energy storage capability, thermal reliability, and thermal conductivity were tested by DSC, accelerated thermal cycling test, and heat flux method, respectively. The leakage proof property and mechanical property were evaluated by seepage test and nanoindentation test, respectively. Compared with NanoPCMs with SiO 2 shell, the NanoPCMs with polystyrene (PS)-SiO 2 shell possess smaller size and bowl like shape, while NanoPCMs with poly(hydroxylethyl methacrylate) (PHEMA)-SiO 2 shell possess larger size and perfect spherical shape. The polymer types have great impact on the supercooling behavior of the NanoPCMs. The polymer-SiO 2 hybrid shell materials endow the NanoPCMs with improved thermal reliability, thermal conductivity, and leakage proof property. More importantly, the compressive load at yield increases remarkably from 14.7 μN for nanocapsules with SiO 2 shell, to >34.6 μN for that with PS-SiO 2 shell, and 65 μN for that with PHEMA-SiO 2 shell.
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
CONSTRUCTION AND BUILDING MATERIALS
·
2023
·
IF 7.4
Runzhuo Cao,Junfen Yang,Guoxin Li,Qun Zhou,Mengdie Niu
Exposure of cement-based structures to sulfuric acid environments can cause significant degradation. Therefore, this study focuses on the effect of nano-SiO 2 on the sulfuric acid resistance of ordinary Portland cement (OPC)-sulfoaluminate cement (SAC) composites (as repair material). Samples were exposed to three concentrations of acid solution. The degradation kinetics, chemistry, and microstructures of the composites were analyzed. The results of degradation kinetics (dimensional change, mass and strength loss) showed that the nano-SiO 2 modified composites had a lower degradation rate compared to the composites without nano-SiO 2 . XRD, TG, MIP and SEM analyses demonstrate that nano-SiO 2 promoted hydration and improved structural compactness, which can not only enhance the diffusion resistance of composites to H + and SO 4 2- , but also form a protective barrier in acid environments. However, diffusion–dissolution-precipitation is still the main mode of degradation in composites subjected to sulfuric acid attack, regardless of nano-SiO 2 content mixed into the composite system.
研究领域:
材料科学
·
土木工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2023
·
IF 3.5
Yuhan Ren,Biao Zhang,Jian Ye,Haoqian Zhang,Zhaoxin Zhong,Yang Wang,Feng Ye
This study successfully prepared a series of novel Y 2 O 3 -SiO 2 composite aerogels using sol-gel methods. The high-temperature calcined SiO 2 -poor aerogels exhibit excellent high-temperature thermal stability in terms of shrinkage, porosity, and BET surface area maintenance. SiO 2 -rich aerogels exhibit more pronounced mesoporous material properties, the BET surface area and pore volume of sample Y2S1 reached 291.04 m 2 /g and 0.50 cm 3 /g, an increase of 278.71% and 297.78% over the pure Y 2 O 3 aerogel, respectively. In addition, compared with untreated mullite fiber, the thermal conductivity of the mullite fiber after impregnation with Y 2 O 3 -SiO 2 composite aerogels decreased by 35.32–45.77% at 300 °C, which is similar to the performance of impregnation with Al 2 O 3 -SiO 2 composite aerogel (38.31%). Moreover, the Y 2 O 3 -SiO 2 composite aerogel with a high BET surface area may have potential applications in the field of luminescent materials such as phosphors due to the intrinsic electronic structure of the rare-earth yttrium and its fantastic optical properties.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Boyong Ye,Ruru Zhou,Caili Wang,Zixuan Wang,Zixin Zhong,Zhaoyin Hou
Polylactic acid (PLA) is popularly used to replace some petroleum-based polymers due to its biodegradability. However, biodegradation of waste PLA requires specific bacteria, stringent conditions and long time. Catalytic recycling of waste PLA to valuable added products rather than composting is a sustainable green routine. In this work, catalytic alcoholysis of waste PLA to methyl lactate (MLA) was carried out over a SiO 2 @UiO-66 derived solid acid (SO 2– 4 /ZrO 2 /SiO 2 ). Characterizations indicated that SO 2– 4 /ZrO 2 /SiO 2 processed large surface area and homogenously dispersed acid sites, and it exhibited excellent performance for the alcoholysis of waste PLA under mild conditions. At 140 o C, the yield of MLA is 92.7% within 5 h, and SO 2– 4 /ZrO 2 /SiO 2 could be recycled at least five times without obvious loss of activity. The specific yield of MLA over SO 2– 4 /ZrO 2 /SiO 2 reached 2678 mg-MLA/g-cat/h, which was higher than that of H 3 PW 12 O 40 , Amberlyst-45, H β , HZSM-5 and α -ZrP. At the same time, SO 2– 4 /ZrO 2 /SiO 2 was also capable of the alcoholysis of waste PLA-based products. A possible pathway of PLA alcoholysis over SO 2– 4 /ZrO 2 /SiO 2 catalyst was proposed.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Dapeng Gu,Guanqun Wang,Suwen Chen,Hongtao Luo,Xiaofan Chen,Ziyu Liu
The traditional high-temperature sintering method cannot achieve the combination of ceramics and polymers for the huge sintering temperature difference. The insufficient interfacial bonding strength of the ceramic matrix is the difficulty in the low-temperature preparation of ceramic-polymer composites. To improve the interfacial bonding strength of Si 3 N 4 (Silicon nitride) ceramic matrix composite, an easy-bonding SiO 2 (Silica) shell was introduced onto the surface of the hard-bonding Si 3 N 4 core by Stober method, to obtain Si 3 N 4 @SiO 2 composite. Si 3 N 4 @SiO 2 /PEEK (Polyetheretherketone) composites were prepared by the cold sintering process (500 MPa, 240 °C, and transient liquid phase is NaOH solution). The dry tribological properties of Si 3 N 4 @SiO 2 /PEEK composites with different PEEK percentages were studied by a ball-disc contact form. It is shown that an amorphous SiO 2 shell with a thickness of 25 nm is chemically bonded onto the surface of the Si 3 N 4 core. The presence of the SiO 2 shell improves the interface bonding strength between Si 3 N 4 ceramic particles. The friction coefficients of Si 3 N 4 @SiO 2 /PEEK composites decrease with the increase of PEEK percentage. Compared with Si 3 N 4 @SiO 2 composite, the friction coefficient and wear rate of Si 3 N 4 @SiO 2 /50 vol% PEEK composite decrease by about 40% and 26%, respectively. The main wear forms of Si 3 N 4 @SiO 2 /PEEK composites are abrasive wear and adhesive wear. A mixed lubrication layer, mainly including PEEK, Si 3 N 4 , and SiO 2 , exists simultaneously on the surfaces of Si 3 N 4 @SiO 2 /PEEK composite and the counterpart ball, respectively, playing the role of reducing friction and wear.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）